Leadlighting Tutorial Lesson 1: Cutting Glass for Stained Glass Leadlights the Right Way
Leadlights are a thing of constant beauty as the light changes and if you have them in your home they will give immense pleasure to yourself and anyone who visits your home. They are even more satisfying if you’ve made them yourself and the best thing about that is there is nothing physically hard or difficult about making a leadlight. Yes it is a little time consuming but the time is yours anyway. And yes, you do need to be accurate in some of the steps, and everyone achieves it, young and old. So if you've always wanted to have a go at it, you'll find just getting started is the hardest thing - but once you've made up your mind and begun, you'll be surprised how easy it is.
I first learnt leadlighting in 1987 from an excellent leadlight tradesman, Lindsay Pring, who served his apprenticeship as a young man at Frederick Ash in Newcastle Australia. They were the premier glass company in Newcastle at the time and as well as normal glazing work, manufactured beautiful leadlights to houses and buildings, not only in Newcastle but far and wide. After completing a leadlight course with him, he was impressed with my work and he was kind enough to employ me for 5 years, so you could say I served an apprenticeship under his guidance and then I went out on my own. I soon realised I would have to teach the craft to make ends meet.
I've taught leadlighting for over 13 years and over 1500 people have learnt and enjoyed leadlighting as a hobby, making their leadlights to a very high standard, which is evident from photos in my 'students work' album. Even though I have retired, I still miss teaching so perhaps I can continue to teach through these pages.
The reasons I have created these pages are many but firstly, when I was selling glass in my business to students who had been taught elsewhere, they would often ask questions on how to do certain things, and I was always happy to give them an answer to help them out. I soon realised, from what was being asked, there was a need for instruction on the correct way to do things. It always upset me and even annoyed me that so many people were not being taught the right way and the most difficult thing about leadlighting, is knowing where to go to get the best instruction. Unfortunately there are some in the teaching arena who have suffered bad teaching themselves and sadly, wrong techniques continue to be passed on to those who know no different. In other words, hobbyists badly taught by other badly taught hobbyists to other hobbyists with no trade background or qualifications whatsoever. I'm not against that, providing the person teaching knows what they are doing. You may find it an advantage to compare what is written here with what others may tell you who have had, or given leadlight instruction before.
I've tried to make these pages the very best you will find anywhere and totally complete - everything I've seen regarding leadlight instruction on the net has always been incomplete, leaving you with a need to find more information. Although some of these pages may seem overly long, it's just so that you won't need to search for more information, it's all here. In fact, only about half the contents in these lessons contain the methodology - the nuts & bolts so to speak, the remaining half is all about stuff that is hard to find, if at all. They’re written in plain language for both the beginner and devotee, but more importantly, they are the correct way to do things. They are given free and I invite you to print them out and collate them into a manual to keep beside you and refer to while you go through each lesson, step by step.
When I first thought about publishing these pages, I considered whether to include photos of my own work. Initially I didn't want to because I thought it would be seen as bragging, which I didn't want but my wife convinced me that people like to look at photos that relate to their hobby, so I relented and included some photos after first publishing these pages. There are many photos at the END of each lesson, I hope you enjoy them and that they may give you some encouragement and ideas.
If you wish to make a comment on these pages the comment box is below the photos.
Certain tools are needed, which are: A quality glass cutter, a 600mm aluminium ruler with a non-slip backing, pen & pencil, running & grozing pliers, a small claw hammer, lead knife & lead snips (not side cutters) about 30 horseshoe nails, a fid, a tooth-brush size wire brush, the very least - an 80 watt soldering iron with a right angle tip, and if you're really serious, a glass grinder to make things easier. (There is more information about these tools and materials as you read each step.)
Materials needed are: Knife lube, 60/40 solder, stearine flux, black putty, black patina, casting plaster, lead polish, glass and lead as required.
LESSON 1 - Glass cutting, 14 pages.
LESSON 2 - Getting started with a simple, clear glass panel, 16 pages.
LESSON 3 - Assembly, 8 pages.
LESSON 4 - Soldering, 7 pages.
LESSON 5 - Measuring and other things, 10 pages.
LESSON 6 - Advanced cutting, 8 pages.
LESSON 7 - Puttying and repairs to broken panels, 9 pages.
LESSON 8 - Reinforcing, 5 pages.
As I have edited these pages from time to time, adding more information as things come to mind, there could be more pages in each lesson than mentioned, so if you intend to print them out make sure your printer is loaded with enough paper. Also when you click the print icon on your computer, set the print to 15 points - you'll use more paper but you will be able to read it easier. If you tick the remove images box you will use less paper, but you may need the diagrams.
If you have difficulty reading these pages you can increase the size of the pages by pressing Ctrl, Shift, +, which will enlarge them to make it easier to read. By pressing these tabs once will enlarge to a slightly larger size, pressing them again will enlarge again and so on. You can reduce if you go too far by pressing Ctrl, Shift, -. After you leave these pages you may need to reduce your home page to it's normal size again in this fashion.
It may also be a good idea to check back every now and then to see if I've added more information that could be useful to you. I'm constantly tweaking these notes just because I want them to be perfect.
Even if you are a first time leadlighter, you can make a leadlight just by following the directions in these pages, after first making the simple exercise described in lesson 2. (there are those who have) But if you still have any questions on anything you are unsure of, feel free to contact me by writing your question in the comment box at the end of any lesson. I am happy to respond to any question. Just remember, there are no dumb questions, each one of us had to learn at one stage and your question may benefit another.
I hope you find these pages both interesting and helpful in your leadlighting hobby and if you know anyone interested in leadlighting, perhaps you can tell them where you found these pages. (The easiest way is to Google leadlighting tutorials or visit leadlighting.hubpages.com)
Sincerely, John Jackson.
So let's get straight into it:
LESSON 1: How to cut glass for making a leadlight.
Glass is cut or divided by means of a small metal wheel which makes a score line or a small V on the glass surface. This score line is then penetrated to achieve separation. The glass used for leadlighting varies between 2 - 4mm thickness, but 3mm is average. Always cut the glass on the smoothest side. Throughout these notes you will find references to cutting and scoring - they are to be taken as meaning the same thing.
If you've never cut glass before, start off by practising on some plain clear glass, as it is the softest and easiest glass to cut, making an easier and cheaper transition to stained glass. Cut the glass directly on the bench, not on padding of any kind as it can lead to problems with breakage because of the glass bending when you don't want it to.
Always clean the glass and the bench before cutting, dust of any description isn't kind to the wheel in your cutter and particularly clean the bench when cutting mirror as any fragments left on the bench can scratch a mirror, even a clean bench can scratch a mirror. Cut mirror on a thin blanket that has been stretched tight and nailed down, just make sure the side closest to you is nailed down on the side of the bench so that you are not cutting over a nail.
If you allow the cutter to lean over when cutting, 3 things will result:
1. Score line failure, particularly on curves - the worst result.
2. Feathers can form on the edge of the glass.
3. Unnecessary wear to the wheel and axle.
It's interesting to look at a quality wheel under a powerful magnifying glass, you would naturally think the wheel would be very sharp for cutting glass - not so, the exact opposite in fact. An average angle for the wheel is about 135 degrees, which is a very blunt angle! What this means is when the wheel is perpendicular to the glass, the angle either side of the point of the wheel is only 22.5 degrees. So you can very easily understand that you don't have to lean the cutter over very far before it's no longer cutting, it's beginning to skate on one side of the wheel and can lead to failure. For most people, holding the cutter so that it doesn't lean over when cutting a straight line is easy enough, but cutting curves can cause you to lean the cutter unawares. You just need to be more conscious and watchful on curves.
USING THE GLASS CUTTER.
The cutter is designed to be held in one hand only. (More than enough pressure can be applied using only one hand.) The other hand is used to stop the glass from sliding on the cartoon. (See Lesson 2 for cartoon definition.) Glass that is smooth and flat on both sides will slide the least due to friction and surface area, glass that is textured or wavy will slide the most, so be careful of this trap when cutting.
Stand upright using your whole arm just slightly bent. If you lean forward too far your arm is bent too much at the elbow resulting in tired forearm muscles. Don't try to hold the pencil cutter at 90 degrees to the glass, (when viewed from the side) as your fingers will slide down the cutter and you will also need to grip it much more tightly which will result in very tired fingers. The pistol grip cutter is angled at about 60 degrees to the handle for a reason and by holding the handle parallel to the glass, the cutter will be at the correct angle.
60 degrees is the optimum angle for ALL glass cutters.
Another reason for holding at 60 degrees is the wheel will always track straight when cutting away from yourself. Think about the front forks on a bike, they are cantered forward aren't they. If they were vertical you wouldn't be able to take your hands off the handle bar as you can with a bike that has the forks cantered forward. It's exactly the same with a glass cutter.
(There is more information about cutters further down under TYPES of GLASS CUTTERS.)
MAKING THE CUT:
When making your first cut and not knowing what to expect, the first 50 - 100mm (2 - 4") will tell you everything you need to know. Listen to the sound the wheel is making on the glass, it should be a soft hissing sound. Another way of describing the sound, it should be a soft clickety, click, click, click - and not a clack, clack, clack! If no sound at all keep going but press a little harder until you hear it and remember the 'slow walking speed'. Too loud, which will be a sharp crackling sound, so decrease pressure – it’s usually the guys who press too hard. Try to achieve the right sound within that first 100mm and you'll probably find it's easier if you're slightly too light on pressure to increase pressure, than if you use too much pressure and having to reduce pressure. It's not surprising to see that most people new to glass cutting tend to overscore - even some with more experience, who should know better.
Start off by making straight line cuts without using a ruler on a square of plain clear glass towards yourself, allowing the cutter wheel to roll off the edge of the glass without decreasing pressure and onto the bench – it won’t hurt the cutter.
This makes penetration and separation so much easier. The mistake some do is reduce pressure as the edge of the glass is coming up and this makes it harder to separate, simply because the cut isn’t quite deep enough at the edge. (Same mistake for curves, see below under freehand or curved cutting.)
Now before trying to separate the glass, examine the score line - separating glass is dealt with further down. If the score line has a very white chaulky appearance, you have applied way too much pressure to the cutter and it would also have made a harsher sound – it’s surprising that only a little pressure is needed.
For every piece of glass there is just the right depth to the cut to make penetration and separation that much easier.
As an experiment on a square of glass, put 3 score lines, 1st one too light, 2nd one what you feel is just right and the 3rd one too heavy. If it's done correctly 1 & 3 should give difficulty in separating, if at all on the 1st one, the 2nd one should separate easily. If you've managed to separate all 3 score lines I would suspect that you haven't scored light enough on the first one, that should also tell you that you don't need a lot of pressure because that pressure was obviously ok. What you are aiming for on the light one is maybe you can separate it but with extreme difficulty.
Now turn the glass on it's edge and examine the depth of the score line on both the one you feel is ok and the one that was too heavy. On the one that was too heavy, the score line depth will be very obvious and noticeable with fissures and serrations to the glass along the score line. The one you feel is ok should look quite different - it should be smoother, cleaner with less fissures and much less noticeable. This is what a perfect score line should look like when viewing on the edge of the glass and this is what makes the difference between easy and difficult penetration and separation.
On the two photos immediately to the right, they show a piece of glass turned on it's edge after it has been scored. The top one is overscored and you can see how the glass has a very wavy fractured appearance with deep serrations in the score line compared to the lower photo, which is properly scored leaving the edge so much smoother. If you click on the photos the enlargement will give a better result, but if you do the experiment as described, reality will show it even more clearly.
You will find on your stained glass journey some glasses will demand a perfect score line and others won't. So it's easier having an understanding of what happens to the glass when you score it. Underscoring or overscoring usually ends up with the same result to the glass, but overscoring will result in damage to the wheel over time.
If you think or know you are overscoring, go back to practicing making a cut then separating, gradually reducing pressure until you can no longer separate the glass. With a little more pressure listen to the sound at this pressure and try to repeat this every time. It doesn’t take very long for this to become automatic. Stained glass being a harder glass will require a bit more pressure, but not much.
NOTE: When cutting thicker glass, 5-6mm (1/4") and over, penetration and separation begins to get more difficult. For straight line cuts place a pencil under the score line and with the palms of your hands on the edges, press slowly but firmly down to the bench to separate. Don't think that because you are cutting a thicker piece of glass that the score line needs to be deeper - it doesn't. In simple terms, the score line's only job is to alter the surface tension on the glass, which causes a weakness at that point and whether the glass is thick or thin, the score line is always the same. To further understand this, go back and look at what I've said about depth of score line.
To recap, you start a couple of millimetres in from the edge, and finish by rolling over the edge with the same pressure throughout. Separate from the edge you rolled over and if you made a good score line it will almost fall apart.
Score lines must be continuous, starting on a side of the glass and finishing on a side, even if it happens to be the same side. (An internal curve.)
Maintain a constant pressure from start to finish. A score line that has uneven pressures applied to it when cutting, will also have a varied depth to the cut - i.e. shallow/deep, which may break out ok in a straight line, but usually results in failure on a curve where the cut is shallow. Look, listen, feel (relating to pressure) are the key things to observe here.
BENEFIT OF USING OIL ON THE SCORE LINE:
Always use an oil-mix for every cut. 50/50 light oil and kerosene. Not everyone likes to fill an oil cutter with oil because they can sometimes leak, making a mess on your cartoon. An easy way around this is to make an oil pot. Make one from a low tin containing a few pieces of felt with the oil-mix in it, only enough to saturate the felt and dip the wheel for every cut. (A handful of cotton wool is also ok as it will shrink when you add the oil.) You may think there won't be enough oil on the wheel to make a long cut just by dipping. When you dip the wheel, the oil will fill the slot above the wheel, which will feed the wheel as you make the cut and go about a metre, but most cuts are only a short length anyway. (just make sure when you dip the wheel that you press hard enough into the felt to fully immerse the wheel to load the slot with oil, just lightly touching it isn't enough.) As well as lubricating the wheel and axle - and this is the important bit, oil serves as a barrier and stops the glass molecules from coming back together. I know what you're thinking so prove this for yourself by making two cuts on a square of glass, one with oil and one without oil. In a month's time, the one with oil will still separate, the one without oil usually will not. Get into the habbit of dipping the wheel for every cut and it soon becomes automatic.
Hot and cold score lines. (Also related to using oil for every cut.) When you first put a score line on the glass it is considered hot and you should try to separate as soon as possible while it is still hot as it is so much easier. It doesn't stay hot for very long, a cold score line gets more difficult to separate the longer it is left. A perfect example of this with modern technology is if you watch the cricket - they call it the hot spot. When the batsman hits the ball it shows up as a white dot on the face of the bat and gradually fades over 15 seconds or so, this is exactly what happens with a hot score line. This is more pronounced if you score dry, although initially it is hotter without oil simply because oil acts as a coolant. Toyo used to sell what they called a 'dry cutter' but the wheel won't go the distance scoring dry all the time.
Glass is defined as a 'super cooled liquid' i.e. neither liquid, nor solid. By mixing certain chemicals and minerals together and subjecting it to a known process, it becomes a super cooled liquid and the molecules do not 'line up' as in metal or wood, which causes the rigidity of these materials. In glass they are random in structure, the same as water and this characteristic allows water's property of fluidity of movement. If you break a piece of wood or metal it will splinter, but you can't break water can you, unless you freeze it. So think of glass as a sheet of ice and ice doesn't splinter on breaking. With a sheet or block of ice, if you score it and break it, it will separate cleanly because all of the molecules are still random. To explain it further in simple terms, if you put your finger in a glass of water it makes a hole, but when you take your finger out of the water it comes back together again, simply because of the viscosity of water at room temperature - not so with ice. It has been proven by macro-photography over a long time frame, that if you put a dry score line on a sheet of glass, over time it will begin to heal itself, i.e. the score line will partially close up. In the same way, glass that is stored in racks vertically gets thicker at the bottom, which has been proven with a micrometer.
(Initially I didn't want to get too much into the technical descriptions of how and why something works or is, as I wanted to keep it simple but for the technically minded, I hope this explains why not to score dry.)
STRAIGHT LINE CUTTING USING A RULER.
These are mostly made toward yourself no matter what cutter you use, i.e. from north to south. Only use a metal ruler with a rubber strip on its undersurface. Unless you are making a cut less than 40-50mm, always use a ruler. Trying to cut a straight line longer than 50mm without using a ruler never results in a good straight line. If you are right handed, making cuts from northwest to southeast using a ruler is also ok, but never try cutting from northeast to southwest, left-handers vice versa. (Also avoid making cuts in an ‘east/west’ direction until you become proficient, too many things can go wrong.) Under the heading 'MAKING THE CUT' above, I mentioned remember the slow walking speed. This is another thing that needs to be observed, whether making straight line cuts using a ruler or curved cuts, (more so with a ruler) it's important not to exceed this speed as cutting too quickly can cause the cutter to 'ride up' out of the glass due to poor control resulting in too shallow a cut. Of course trying to cut curves too quickly only results in inaccurate cutting.
Common things that can go wrong using a ruler:
1. Ensure the cutter is parallel to the ruler – if not, the wheel will scratch rather than score and a scratch has no penetrating ability. (Even with a pivoting head you can still manage to get it wrong.) Do not cut against the bevelled edge on the ruler where the numbers are; you can ride up over it, hold the cutter hard up against the flat side.
2. Give yourself elbow room, most people have sawn a piece of wood – you need elbow room don’t you. It’s the same with cutting glass; make the cut away from the centre line of your body by giving yourself elbow room. If you try cutting glass on your body centre line you will steer away from the ruler as your elbow moves to clear your body.
3. Make sure you have a very firm pressure on the ruler to avoid twisting or sliding. Spread your thumb and index/middle fingers over the centre of the ruler.
4. Maintain a reasonable firmness against the flat side so that the wheel will not wander away from the ruler.
FREEHAND OR CURVED CUTTING.
These are ALWAYS made away from you. It’s easier to follow the shape this way as your hand is not in the way. This may sound difficult at first, but in reality it isn't. You will need to be in a position (but not bent) so that you can see the slot, or wheel housing lining up on the cartoon line. (See lesson 2 for more about this.) Remember you are still holding the cutter at 60 degrees and to see the slot, the angle from your eye to the wheel will be about 70 degrees, which means you can also see where you are cutting over the cartoon line and so that you are in a comfortable position - not bent too far forward.
At first you will tend to wander everywhere except beside the cartoon line.
The simple answer – SLOW DOWN!
The 'speed' for cutting curves is much slower than cutting a straight line.
Start off by drawing a curve like a Harbour Bridge about 300mm (12") long and practice cutting this simple curve over and over on clear glass until you get reasonable accuracy and you feel confident, rather than wasting stained glass. On the above curve drawing, let's relate to it as being horizontal. After making cuts on a third the glass, turn the drawing to vertical and upside down as well to get used to cutting in different directions. (You'll need to turn the glass as well.) Just try following on the line at first, you’re trying to achieve accuracy here so you don’t need to separate each cut, you can practice separation on another piece of glass. On a square foot you can make about 50 or so cuts close together and you can tumble the glass, (turn it over) and make cuts on the other side. When you tumble the glass, turn the drawing as well so that you're cutting the curve the opposite way as well to avoid repetition. Now you’ve begun to understand what accuracy means! In Lesson 2, we'll take accuracy to another level.
When cutting curves, it’s better to penetrate gently from both ends as glass likes to break in a straight line. Even a simple curve like a ‘Harbour Bridge’ can cause problems at times if you don’t penetrate at both ends first. Penetrate simply means to start the separation process and can be achieved either by hand or running pliers.
When penetration begins and done quite slowly, it looks like the glass is splitting along the score line, but it has only gone part way through the glass. As soon as you stop this process the penetration will stop running – it needs a motor, or force to continue running. By starting the penetration again from the other side, this splitting effect will join up to the other penetration and the glass will then separate.
Sometimes it’s easier when penetrating by hand to first tumble the glass and press over the score line on top of the curve with your thumb. After you've started the penetration, keep chasing the penetration out to the edges from where you started. You are aiming to 'see the score line run' so do it just hard enough to see it happen - don't press so hard that it penetrates and separates in one go as that can cause problems with some curves. After you've completed the penetration using this method and the waste is still connected to the principle shape, turn it back to the face side again and separation will be so easy it will almost fall apart. When using this method DO NOT press on padding of any kind as it can cause the glass to bend in a direction you don't want it to. Press only on the flat surface of your bench. More about this in Lesson 6, particularly with points.
Think of it like this, on a straight line cut the glass bends ever so slightly before it separates; it’s similar for curves but with an added difficulty. This simple 'harbour bridge' curve is like a hill and the score line is dictating to the glass what we want to happen to it. The glass is obeying the score line up to the ‘top of the hill’ and so far it will do what we ask. As the penetration goes up and ‘over the top’ the glass is being asked to bend in a different direction but it really doesn’t want to. Then as it comes down the other side we are asking it to bend the other way again and it’s about here that it can develop a mind of its own. What it really wants to do is continue straight at this point and if we have neglected to penetrate from this end as well, the glass can penetrate or twist down at an angle under the score line, sometimes over 45 degrees. You can understand a straight line cut will produce a 90 degree angle at the score line, (in 99% of the time) it is this 'last curve' that causes the penetration to radiate away and under the score line. This usually happens when trying to penetrate and separate the glass too quickly, or in one go instead of two easy steps - but if you do it gently you will see the score line run more slowly, which gives you more control over it, being able to stop when you want to. If we first penetrate gently from one side up to the top of the hill, stop, then penetrate and separate from the other side, this will fix the problem. You can incorporate this technique on most curves. So you can see from what has been said above about glass liking to break in a straight line, and it's quite happy to do that, it's the curved lines that introduce the problems. It's just a matter of firstly making a good scoreline, breaking it out as soon as possible and using the correct techniques to do so.
Try to have at least 10-15mm minimum wastage to cut off the edge on curves; trying to be miserly will end up with more problems than what it’s worth.
Because we cut away from ourselves on a curved cut, we cannot allow the cutter to roll over the edge of the glass as in a straight line cut as the cutter will damage the edge of the glass - because of the 60 degree side view angle. (You’ll understand what I mean when you try it.) Simply stop cutting when the cutter is very close to the edge without reducing pressure.
Sometimes when cutting small, tight curves very slowly you might not hear any sound. This is where ‘feel’ takes over. You need to get used to a certain feel as well as sound. You may find it easier in your early stages, to give the cutter a 'kick start' by using the thumb on your other hand placing it behind the cutter and pushing to start off. Just make sure the palm of that hand is still holding the glass firmly down on the cartoon. Some can find this easy to do, others find it awkward, you can decide if you like it.
To recap, start a couple of millimetres in from the edge and finish a couple of millimetres in. Penetrate from both edges, using running pliers if it’s too difficult by hand.
(This is the most contentious issue.)
Many years ago, leadlighting was not done by those in the beginnings of the glass trade - it was done by plumbers! The simple reason is that plumbers worked with lead so it initially became an offshoot in the plumbing trade. Because of this, incorrect methods of cutting and separating glass evolved and have unfortunately filtered down and survived til today, even crossing over into the glass trade. It's surprising that many glass tradesmen still use the wrong technique in regard to proper separation when there is a better way. Perhaps they weren't taught properly in the first instance and it's difficult to get people to change, particularly if they were using the wrong method for some time and also because most people believe the first things they were told.
It is primarily the wrong and misleading information about separating glass that I have seen written in leadlighting 'howto' pages on the net - and even leadlight books that annoys me so much. I apologise if I seem unduly harshly critical, but words alone cannot express my intense dislike of information that is simply incorrect - not for the person, they just don't know.
There is only one correct way, there are many wrong ways, yet so many persist with wrong methods taught by others who don't know themselves, or methods they have devised themselves but if they would only realise - the right way is always the easiest way.
I'm sure any tradesman worth his salt and knowing the correct method to do a certain task, would be equally annoyed at seeing something done the wrong way. Give the correct way a try for a while and you be the judge.
Thankfully there are some who still know the correct way to cut and separate glass, so here it is:
THE CORRECT & PROPPER WAY FOR SEPARATION.
1. After scoring, LEAVE the glass flat on the bench but slightly overhanging the bench so you can get your fingers under it. If you lift a large sheet it will sag in the middle, which is exactly what you don’t want.
2. Index fingers pointing together in a slight V away from you under the glass and the knuckles on your index fingers are always facing the floor. (See photo below.)
3. Thumbs on top slightly apart and directly over your index fingers.
4. Grip reasonably tightly and rotate both hands, pushing index fingers upwards. (This rotation is not overly exaggerated, it's only slight before actual separation.)
Practice the last 3 points without any glass in your hands first.
If it fails to separate easily the first time, the problem is usually from two things: you've either made a poor scoreline, either too heavy or too light, or you need to grip it tighter. If gripping it tighter fails to work, it can only be a poor scoreline.
(Not wanting to blame the tools, but the condition of the wheel can also have an adverse effect, particularly on the cutters that don't have a tungsten wheel.)
If ever your index fingers are pointing back at you, STOP.
That last sentence refers to the 'wrong way' and is why I've put it in bold print. You can separate glass in straight lines with limited success that way, BUT the risk of injury is much greater. Trying to penetrate and separate curves is even worse. The right way is very easy to learn and if it doesn't happen the first time don't give up, just persist and success will follow. (See also further down under Running Pliers.)
To give you an example, when I was teaching, the first night was all about how to cut and separate glass properly and we first started off with a square of glass about 400 x 300mm. (16 x 12") After showing the class how to do it, I asked them to make one cut to cut the glass in half and then separate it and I watched each person in turn so that I could hear if they got it right within that first 100mm - and there were rarely any failures. I then asked everyone to cut the two halves they had left in halves again, so they ended up with four pieces of glass. From there I asked them to continue cutting each piece of glass into halves again until they could no longer separate the pieces in half using the technique described. Most people were able to cut and separate a strip of glass in half that was about 20mm wide (1") using their fingers only! Do you think you could cut and separate in half, a strip of glass only 20mm wide using the wrong technique with your index fingers pointing back at you? No, you can't - you'll need to use running pliers and what I'm saying here is you will go further if you use the correct method.
Once you understand the mechanics of this method from the above text and photo below, you will see that if your index fingers are pointing back at you, as well as your other fingers that are below the glass, all the knuckles on your fingers are usually hard up against each other. BUT to separate glass after it has been scored, first it has to bend very slightly before it will separate. If all your knuckles are hard up against each other, it's difficult to do the rotation as in step 4 - YOU are preventing the glass from bending slightly and you are really trying to pull the glass apart, which is how you can do yourself an injury and I have seen it time and time again.
However, some can still find an argument for doing it 'their way' and if this is the way you've been taught and you don't want to change, I can't stop you, that's up to you. But if you just give the CORRECT way a try, you may surprise yourself. When your index fingers are pointing forward as described, you will never hurt yourself.
MAIN TYPES OF GLASS CUTTERS:
It’s well worth the expense of buying a good quality cutter with a tungsten carbide wheel. A metal $8 cheapie from most hardware or tool stores as well as leadlight shops, will last about two or three weeks, not to mention the wastage of glass after it gets blunt, because the hardness of these wheels isn't the same temper as a quality wheel. Also the larger wheel on these types of cutters don’t like to turn tight curves, a small wheel is best.
There are two main types of oil fed cutters that I would recommend, the pistol grip and the pencil grip, made by Toyo, Mitsuboshi and K-Star as well as other brands.
There is also the Thomas Grip cutter, which is cradled between the thumb and index finger, but I'm reluctant to recommend it as it's too easy to overscore with too much pressure simply because of the way it fits into your hand.
Any of these cutters that have a quality wheel will last a very long time provided you don't abuse them, mine is over 20 years old and still going strong. They can be bought at most stained glass suppliers. As well as glass cutters, they can supply all your tools. Anyone in countries outside Australia can easily do a search on the net in their own countries.
A relatively new cutter from Toyo is the Tap Wheel cutter and is similar to the Thomas Grip, which as the name suggests taps the glass via a cam, tapping the glass 8 times per revolution of the wheel. I do NOT in any way recommend this cutter, as tapping the glass via the wheel will cause fissures to the score line which become fractured and can lead to failure, particularly on curves. Successfully separating glass relies on a 'clean cut' with a minimum of serrated fissures on the score line.
www.amazon.com can also supply tools worldwide. With the Aussie dollar on parity with the US dollar you will actually save money by buying whatever tools that Amazon sell, rather than buying here. For instance you can buy a quality glass cutter + freight cheaper than you will buy anywhere here. Even a grinder sells for around $100 and the freight won't be much. Try getting one here delivered to your door for that price. I have been using a Glastar Diamond Star grinder for years and Amazon sell it for $99. (Have a look at Amazon's grinder prices at the bottom of this lesson.) I paid three times that much for it over twenty years ago. If you need tools I would recommend investigating Amazon.
The pistol grip is usually the most popular with beginners because there is no technique to master, it’s just like holding a bread knife - thumb on top.
Pros…easy to use,
Cons…more wrist action following curves, which can be tiring and it’s not too difficult to overscore with a strong arm as more pressure is easily applied to it.
The pencil grip is NOT held like a pencil as very little control is gained over it, as well as causing tired fingers. The correct method is to place it in between the index and middle fingers and wrap the index finger over the cutter, which locks it in, with the thumb in support behind it. (See photo 1st page.)
Pros...curves are made easier by 'twiddling or twisting' the fingers,
Cons...a little effort to master the grip and if you want to use this cutter, take the time to get used to it and use it properly.
If you don't hold the pencil cutter the correct way as described, there is also considerable wrist action, the same as a pistol cutter if you hold it like a pencil on curves. There is a huge benefit in holding it the correct way for cutting curves as you will discover, if you persist and learn to use it properly.
I have seen where some people were taught to hold the pencil cutter slightly different to the correct grip - instead of holding it as described, it was placed in between the middle finger and the ring finger, with the middle finger on top and even though it appears only a slight change, this causes 2 MAJOR problems. It causes a very extreme and pronounced twist in the wrist to hold it vertical when viewed from the front, simply because the 'angle' in the hand has changed, which leads to unnecessary fatigue and it also causes the cutter to lean over quite significantly. If you hold the pencil cutter the right way as described and then this other way, you'll see what I mean. Just try it with a pencil, I can't imagine how anyone could find this comfortable.
Any deviation from the correct method of holding the pencil cutter is usually done because no effort has been spent to go through the learning curve - it seems too hard! In the years that I was teaching I saw many strange ways of holding a pencil cutter, all of which I knew if they would just try the correct way and take the time and learn to use it, it would be so much easier for them. After some gentle persuasion, I convinced most of those using the wrong method to try again and after a while 99% told me, yes you were right. I'll just have to live with the 1% who wouldn't change - their attitude was, this works for me.....and it was usually this 1% who had the strangest method. Oh well, I can't change everyone, you can't teach anyone who doesn't want to learn! I can say this now because I too was using my cutter the wrong way, til I was put right.
Both the pistol and pencil grip cutters can have either wide or narrow cutting heads. The wide head is only useful for cutting straight lines with a ruler, not too good for following the line cutting curves simply because of the extra distance between the wheel and the face of the cutter, creating an error. EG. When driving a car and making a turn, the rear wheel doesn't follow the same curve as the front wheel - same thing happens on a wide head cutter. The best all round cutting head is the narrow head - equally good for straight line cuts using a ruler, best type for following a curved shape on the cartoon. Whatever cutter you buy, make sure it has a narrow head or pattern cutting head.
Diamond tipped cutters are only good for cutting straight lines with a ruler - useless for cutting curves, a wheel is needed to cut curves.
You can make your own custom made cutter like I have if you like the pencil grip. The Red Devil has the worst wheel but the best grip; you hardly know it’s in your fingers because it’s so slim. Once you've held this cutter in your hand you will understand that using the correct method is so easy with this handle because it is less tiring on your fingers. They got it right so many years ago and it makes you wonder why the manufacturers of the modern glass cutter haven't used it.
Of the different types of cutters on the market, the pencil cutter is by far the best to use in the long run but as mentioned, it does take a little time to get used to it. The first time you try to use the modern pencil cutter using the correct grip, it seems quite a difficult animal to tame because the barrel of the pencil cutter is of a diameter that seems foreign in the fingers. This makes it feel larger than it really is - and this is what causes some to revert to holding it like a pencil, which is the wrong way. And any tradesman will tell you if you use a tool the wrong way, you'll only grow so far.
So if you want to use a pencil cutter but it seems awkward, this is the way to modify it to make it so easy to use.
Remove the plastic handle from the brass ferrule on your oil fed pencil, or pistol cutter by unscrewing it in a vice with pliers. Now you have to modify the Red Devil by cutting the tip off just behind the wheel with a hacksaw or simply break it off in a vice. File down the nibblers (what look like teeth) until it fits inside the brass ferrule, (which may need drilling out) and glue it in with Araldite. On some of the newer glass cutters the brass ferrule is shorter than the older models (mine was an older model.) These shorter ferrules may not lend themselves to being drilled out very deep, if at all. An easy way around this problem is to get a brass or copper tube that just fits over the shorter ferrule - make this tube to cover the length of the ferrule and the red devil cutter with the nibblers filed down to fit in the tube and glue it all together with araldite. Just make certain the pivoting head is correctly aligned with the handle. You now have a perfect glasscutter, but you'll need an oil pot. I can assure you it's worth the trouble. If you visit a hardware shop and hold a Red Devil cutter in your hand you'll see how comfortable they are.
There is a company that actually manufactures what I have described above, which is MacInnes Tool Corporation www.macto.com 1700 Hudson Ave, Rochester, NY 14617. (585) 467-1920. Their cutter is a little on the expensive side at $54.99 US compared to the likes of Toyo but the quality is unsurpassed. If you would like to have a professional quality cutter, you won't get a better one. Have a look at the three photos included here on the right, they make a right and left hand cutter as shown in the middle photo so specify if you decide to order one. The lower photo shows a close up of how the brass clip is removable, which holds the wheel and axle in place and this is a left handed cutter. You can see how the brass clip overhangs on one side and rides against your ruler for straight line cutting. For a right handed cutter it overhangs on the other side. Also order it with a 5/32" # 4 wheel which is 134 degrees and is suitable for cutting stained glass. Once you've tried a cutter with a Red Devil type handle, you won't go back to using a Toyo Pencil Grip, simply because of the comfort gained, the question will be do I modify my Toyo or buy a MacInnes Pro. If you've already got a Toyo, either pencil or pistol grip, it's cheaper to modify the Toyo as described but if you're starting out you might want to get the MacInnes.
Is old glass hard to cut? No, a myth but be careful of Drawn glass. Some people think that old glass must be brittle – not so, glass remains the same as the day it was made. Yes, glass is subjected to the ravages of the elements, but that doesn't alter the structure of the glass. If an old piece of glass proves difficult to cut and separate, that's how it was made. Because glass is made using better techniques today, most glass types are easy to cut and separate with a few exceptions. I have found from cutting and separating old glass, (100 years old) the majority have been relatively easy, some very easy and only a few gave any problems.
True Drawn glass is getting harder to obtain now and you can pick it by looking at the glass at an angle. It has a random waviness, sometimes with bullseyes or minor imperfections, which has a nice appeal when restoring old windows or cupboard doors and is keenly sought after. You will also often see it in old picture frames, which is usually too thin for windows. Drawn glass is made by extracting the molten glass vertically through rollers and can sometimes be a little harder to cut because of the stresses within the glass during it's manufacture. Sometimes you can get Drawn glass at house or building wreckers and you will find it in old timber window frames. You may have to do a bit of searching to find it but it's worth the time and trouble as it has so much more character over Float glass. If you do find some at the wreckers, don't alert the guy to what you've found, for all intents and purposes you're just looking for an old window frame. Telling him what it is may mean you'll pay a much dearer price for it! Clear glass that is used today is called Float glass, as it is made by floating molten glass over a bath of molten tin and is perfectly flat with no texture, hence the name.
Some glass types have a soft surface, whilst others can have an extremely hard surface.
(Some opals and some yellows and oranges can be hard and this is just a general guide.)
Cutting a right angle out of glass is impossible; the corner must have some radius. Cutting an accute angle such as in the background shape behind a leaf is also impossible, there has to be a break line from the tip of the leaves. (More about that in Lesson 2.)
A gap in a score line is often caused by cutting too fast, always score slowly. (A slow walking speed.)
NEVER, NEVER GO BACK OVER A SCORE LINE. It will lead to failure because the score line instantly becomes fragmented and rough. You get one chance and one chance only at making a good scoreline - there are no second chances at this. It also causes untimely wear to the wheel and other than dropping it onto a concrete floor, this is probably the worst abuse you can do to your cutter.
A perfect score line looks as if it was seared with a hot knife and with very little fragmentation to it. (Have a look at an overscored score line under a powerful magnifying glass before trying to separate it, and you’ll know why it fails.) The fragmentation, which looks like hacksaw teeth serrations along the score line is what causes the failure, breaking out in one of these serrations. It doesn't have to be a curved line for this to happen either, it can happen on a straight line as well. If you know you have failed, discard that section by cutting it away. No matter what you may have heard or read, just don't do it!
Except in certain instances, (see Lesson 6,) NEVER tap under the score line to separate glass, which is known as score line shocking - It’s totally unnecessary because it can cause shelling to the glass along the score line. Sometimes these 'shells' can be so large the lead doesn't cover them, which will make them very noticeable in your leadlight and you don't want that. This is another thing that is wrong information. A far better solution, particularly for curves is to tumble the glass and press with your thumb over the score line on the reverse side and is described above under cutting curves. A straight line is the easiest of all to separate and whether you do it by hand or use a mechanical advantage, it NEVER needs tapping to achieve separation. You can still employ tumbling the glass and pressing over the score line, the same as a curve if you want to, but never tap under the glass.
Should the glass you have cut have a feather on one edge, an off-cut can be used to scrape upwards at an angle to remove it. Best to remove it immediately before you put it away for assembly as feathers are razor sharp and it will find your finger when you are searching for it.
Running and Grozing pliers.
Are a mechanical advantage that can be used to penetrate and separate glass. Try to use your fingers wherever possible to develop a feel for the glass, rather than totally relying on a mechanical advantage. However, I understand the fear that some people can have about handling glass and if after trying to separate glass using the correct method mentioned above and you simply can't manage it - rather than see you use the wrong method, if separating glass by hand makes you nervous, running pliers will become your second favourite tool.
Running pliers placed over the score line in the direction of the cut and lining up the centre mark on the score line, the curved nature of the jaws will give an upward pressure under the score line and divide the glass. They are handy to start penetration on a difficult curve. SQUEEZE GENTLY when using.
By squeezing gently when running a curved score line like a 'harbour bridge' as mentioned above, you can easily stop the penetration when YOU want to. If you don't squeeze gently you won't be able to stop the penetration when you want to and it will all be over before you know it.
The metal ones are better quality than the plastic ones. The adjusting screw is to set the jaws so that they don’t close completely – set it to about 4mm in the jaws. Don't discard the silicon covers on the jaws - I've seen people do that!
To use grozing pliers, place jaws within 1mm, and at right angles to the score line at the edge of the glass. They are simply doing what your fingers can’t and are usually used when removing a narrow width or very small internal curves. One of the jaws is flat, the other is curved – the flat jaw is placed on the same side as the score line. Grip tightly and separate the waste piece. The narrowest strip you can separate using grozing pliers is the thickness of the glass.
They can also reduce or change the shape of glass – it is rough but quick. This is called grozing and you reverse the jaws in this instance. Hold them reasonably loose as you roll over the edge to remove fragments so the piece will fit (it needs a little practice) but a grinder is the best option.
The 'technique' that I use for small, or shallow internal curves - say 50 mm wide but only 15mm or so deep, is to place the jaws as already mentioned, close to and at right angles to the scoreline, even though it's a curve. Then grip tightly on one side of the curve at the edge of the glass in the waste area and hold the glass in your other hand with your fingers as close to the score line as possible.
Now very gently, bend the waste piece until you hear a faint click. At the same time you should see the penetration begin. When these things happen, stop and repeat on the other side of the curve. Now that both sides have been started you can either tumble the glass and press in the middle of the curve to completely penetrate, (which you must do if it's a small, tight curve as mentioned below) or if it's only shallow, grip in the middle of the curve and remove the waste. The fact that you've started the penetration at the edges it should break out cleanly. Until you get confident it may be best to leave more glass in the waste area so that you can trim the excess off after you remove the curve. (See Lesson 6.)
You can also use running pliers for very shallow internal curves to do the same thing by first starting the penetration on one side of the curve first, then remove the waste completely from the other side of the curve.
But if you were removing the waste from a small, tight internal curve, eg. a full half circle about a ten cent piece in diameter, (20mm) which could be under a teardrop shape in traditional work, running pliers are NOT the ones to use simply because they exert pressure the wrong way in this instance. You'll find it's better to use the grozing pliers as in the method described in the 'technique' above and also refer to putting a wedge score line in after penetrating completely, as described in Lesson 6 under internal curves.
In most cases, the vertical line above the teardrop continues below the teardrop, making the shape easier to cut out, but sometimes the teardrop can end on a horizontal line that bisects the lower half of the teardrop.
Glass won’t bite if you handle it correctly. Wear protective clothing and suitable shoes.
If a piece of glass falls to the floor, an instinctive reaction is to try and save it with your hand or foot – don’t, get out of it’s way and let it fall. If you have a square of carpet down where you are working, whatever falls usually won’t break.
When carrying large sheets of stained glass, NEVER carry it flat or in front of you, carry it vertical and to one side. When carrying large sheets of glass to the bench, hold it in the vertical position, place against the side of the bench so that half of the glass is above and half is below the bench. Rotate the glass to lie flat on the bench then slide the remaining half onto the bench. Never lift glass up along its edge, particularly a full sheet. If there is a start or beginnings of a crack in it, it will break in two as you lift it; simply reverse the method of placing a sheet of glass on the bench. Don’t leave glass hanging over the bench – it will cut you. Most accidents are caused by carelessness – enough said.
ACCURACY is achieved faster scoring slower.
(What follows probably belongs in Lesson 3 - assembly, but I've added it here to help you understand the need for accuracy.)
It is very important to try to be as accurate as possible when cutting curves. Straight lines are easy for accuracy, but some curves will offer a challenge. Large leads will hide innacurate cutting, but there are times when fine leads are called for. (See Lesson 2 for lead description.)
In regard to this, supposing you were using a 6.5 lead in certain areas of a leadlight, which is an average medium size, with a mix of different sizes. Thinking about how much coverage the leaves of a 6.5 lead has over the glass, consider this: subtracting the heart, which is 1mm and 5.5mm is remaining in total. By dividing 5.5mm by 2 = 2.75mm. So that is 2.75 or nearly 3mm on each side of the heart for coverage on the glass.
I would expect a complete beginner would have reasonable, acceptable accuracy in a short time cutting glass on an easy curve for this lead to completely cover the glass – without any gaps and without using a grinder.
But suppose you had a flower in the design and because the petals are delicate, you want to reflect that in the lead choice. Let’s consider a 3.2 lead for this.
Using the same maths, subtract 1mm for the heart, which leaves 2.2mm. Divide this by 2 = 1.1mm of lead over the glass for coverage! It’s not a lot is it?
If you want to use this lead in this situation, a grinder is mandatory. It takes considerable time to cut curves accurately for fine leads without any gaps if you haven’t got a grinder. The only time I would suggest to use a 3.2 lead without a grinder, is in a straight line. Without a grinder, I wouldn’t suggest you use anything less than a 4.6 lead for curves. This isn’t to scare you; it’s to state the facts.
A valuable tool for accuracy perfection is a glass grinder. A way to describe a leadlight is it’s like a jigsaw puzzle in glass. If a jigsaw was poorly made or cut, it would be difficult putting it together – well a leadlight is very similar. You can imagine that laser cut glass would be a perfect fit, so if glass is poorly cut with little or no attention to close accuracy, you will struggle through the assembly stage and it will not be the joy that it is meant to be. It’s in the early stages of developing your glass cutting skills, and it takes a little time to achieve the accuracy you would like, this is where a glass grinder is the difference between stress and happiness. A grinder in today’s $’s (2006) are about Au$295. (I know this is a plug, but they're cheaper through Amazon and if you have a look at the prices for grinders below, the Glastar Diamond Star is the best value for money.)
Accuracy eventually comes – like everything, the more you do the easier it gets. If you’re not prepared to invest in a glass grinder, start off by making some simple sun catchers that consist of a few pieces with simple cuts to build up experience.
If you’re an ‘I want it now’ person and you want to make that fantastic statement in or beside your front door first up, buy yourself a glass grinder which will provide instant accuracy. A grinder is in no way meant to replace a glass cutter or cause lazy cutting accuracy - always try to cut the shapes as best you can first before grinding. Constantly check the shape over the cartoon to make sure you haven't ground too much, which only causes another problem.
Having a grinder you will find as your accuracy improves you will grind less and less and I find I still use my grinder on almost every piece I cut, but it’s just a touch. If you know anyone who does leadlighting, ask them if they have a grinder – nine out of ten will say yes, I couldn’t do without it. Without a grinder you struggle in your early stages and usually don’t make anything spectacular. There are two glass grinders on the market that I would suggest - Glastar, which makes the Diamond Star and Inland, which makes the Wizling. Both are as good as each other. On a new grinder adjust the head so that the cutting surface on the bottom of the grinding wheel is just below the table surface. When this section wears out, lower the head 3mm for a new surface and you can do this 5 times, so they’re fairly economical. Even when you've completely worn out your grinding wheel, a replacement is far cheaper through Amazon. You can buy them singularly or as a pack as in the photos on the right. Grind with the glass flat on the table. (Make sure you keep the water up to the spillway underneath the table or your wheel will wear out prematurely.)
Just a word of warning about grinders, make sure you wear protective glasses while using your grinder or get the eye shield attachment. Prolonged grinding sends a lot of very fine glass particles into the air - inevitably into your eyes, which can cause injury. You only have to wipe your glasses with your finger after about an hour of grinding to see the glass particles on your finger to understand what will happen to your eyes without any protection. One more little hint, glass is very sharp along the edges you've cut and pressing reasonably small pieces of glass against the grinding wheel can cut your fingers if you're not careful. To avoid that, just very lightly run round the entire piece at 45 degrees to the wheel on the face side only to remove that sharp edge and you won't cut yourself. Also don't force the glass too hard against the wheel, let the wheel do it's work and it won't get clogged and it will last longer as well. Keep an eye on the foam sponge behind the wheel, it needs to be in constant contact with the wheel for lubrication and after some time the wheel wears it away and if it's no longer in contact, the wheel isn't being fed with water and will wear down so much quicker. Replace it with a new square of foam as it happens.
If you've never made a leadlight, I strongly urge you to first read and understand every lesson and then make the simple exercise panel described in Lesson 2. Tackling a project too complex first up will lead to unnnecessary hardship and you may even likely give up. However, after reading all the notes you could still be thinking there is so much here to know, just remember, leadlights are made one step at a time. After reading it all, go back and tackle the process step by step or lesson by lesson and after you've completed one step you'll be thinking, that wasn't so hard, what's next - and so it goes.
I understand those of you who have had no experience in making leadlights before may still be a little daunted by thinking I won't be able to do this, could I ask that you at least read all the 8 lessons before you close your mind to having a go at it. (There's nothing to be gained by me in encouraging you to do that, I'm just thinking if you've read this far why not read the rest, or print them out for a future time. Who knows, these pages may not be here forever.) You may find it's easier than you think and you just need the confidence to start, it really isn't that difficult. It will be a help if you know someone who has done it before, particularly if you can have a look at what they have made, which may give you the confidence to begin - ask them how was their experience. Of course there will be some who didn't get good instruction and you may get a negative response, but please don't be put off by someone's bad experience when there are so many success stories. In the years that I was teaching leadlighting at least 95% of every class had never done it before and they were all very nervous at the beginning of the first night but by the end of the night, all went home very excited at mastering basic cuts and glass separation. Then by the time we had all made the first exercise by week 4, all that nervousness was replaced with a desire to do more. In fact for so many I had to apply the brakes because they were so keen to get into it even before they had the rest of the course under their belt. By the end of the course they were sorry it had ended but all were eager to do more. The way I had conducted my classes was different to most in that I never gave hand-out notes, I tried that in the past and found that some didn't read them. So I made students write their own notes from what I narrated from my own notes, which were not as detailed as you will find here simply because of time constraints, which is a plus for you. The other interesting thing was that 90% of my students were women!
This ends the text for lesson 1, scroll down to just above the comments box and click for lesson 2.
I have produced and offered these lessons free of charge however if at the end of the lessons you would like to make a donation, you can do so to my PayPal which is email@example.com
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© 2010 John Jackson