Leadlighting Tutorial Lesson 4: Soldering a leadlight and using the right flux. Making a tinning pot.
Soldering is not difficult and even becomes very enjoyable once you learn the correct steps. It can be done either sitting or standing, whichever you feel most comfortable. Solder is bought either in stick form or a roll. The solder on a roll looks like wire and is about 3mm thick and is the easiest to use.
Remember that using too much solder, or any more than necessary doesn’t make the join any stronger – it just looks very unsightly.
No one sees the perfect cutting you’ve done because it’s covered by the lead, no one sees the perfect lead joins you’ve tried hard to achieve, because they're covered by the solder, but everyone sees careless soldering! (Steps 7, 8 & 9 being the most critical points.)
STEPS IN SOLDERING:
Step 1. Only use 60/40 solid core solder, never use a resin core solder as it leaves an unsightly resin stain around the join, which is difficult to clean off. Solder is made up of tin and lead, the first number always refers to the amount of tin present. 50/50 solder may also be used, but not preferred because of the higher temperatures involved. The reason for using 60/40 solder is because tin (in its raw state) has a lower melting point than lead. Between 60/40 and 50/50 solder, there is a difference of 45 degrees in the melting points of the 2 solders. (temps listed are in Fahrenheit) This is beneficial as it reduces the risk of melting the lead in the leadlight.
To explain these melting points a little further, 60/40 solder melts at 374 degrees and on cooling, solidifies at 361 degrees - a difference of 13 degrees. 50/50 solder melts at 419 degrees and on cooling solidifies at 365 degrees, solidifying almost at the same temperature as 60/40 solder, but with a difference of 54 degrees between melting and solidifying. You may think that because there is a larger heat band of 54 degrees in 50/50 solder it would be easier to use. NOT SO. Lead melts at 621 degrees, so there is a larger buffer with 60/40 solder than 50/50 solder - and that buffer is 247 degrees for 60/40 solder and 202 degrees for 50/50 solder. BUT in fact, we actually solder at a much higher temperature than the melting points of both solders, sometimes not far under the melting point of lead! By using 50/50 solder the risk of melting the lead is much, much greater, simply because of the melting point being higher, the buffer is lower, making 60/40 solder far safer to use. This technical information is not scare you but to encourage you not to use 50/50 solder, as I know some have been taught to use it.
There are some who will say that 50/50 solder gives a nicer looking join than 60/40 because it will 'hold up' on the join and not collapse through the join, and this may well be so particularly if your joins have gaps in them. Even so if you intend to be a good, proficient leadlighter you should always strive to ensure your joins have a minimal gap so this doesn't happen and 60/40 solder will be much easier to use for the reasons stated above. This is even more so for beginners - having a wider buffer with 60/40 will make it easier to successfully transition through the learning stage. After you become proficient at soldering, you can try 50/50 to see if you like it, but I don't think many will.
(For anyone interested in making copper foil suncatchers or lampshades, the following may be useful. Two solders are used, for a suncatcher or free-standing panel, 50/50 is used on one side, 60/40 on the other side. (On a lampshade it is preferable to use 50/50 on the inside FIRST.) In all foil work, a liquid flux (Bakers general purpose) is used and the first side is soldered with 50/50 solder. (Stearine flux isn't suitable for foiled work, stearine flux is used on lead came. Just remember what I've said at the end of Lesson 2, that liquid flux can produce toxic fumes.) I find the easiest way to apply the liquid flux is with a cotton bud. The method I use for soldering both sides is first tack solder the panel together at strategic points on the first side, then put small 'blobs' of solder every 5mm or so along each seam. Then with an up and down motion to your soldering iron, move slowly along the seam melting these blobs as you go to form a molten bead, which will solidify as you progress. Your aim is to try to create an even, nicely rounded 'lead line look' and you may have to add solder here and there to get the result. If your cutting isn't accurate the solder will collapse in spots and fall through and these gaps have to be filled with solder, which is not the best of looks. After allowing the panel to cool the panel is turned over, fluxed again and 60/40 solder is used on the second side in the same fashion but don't be too slow. If you used 60/40 solder on both sides, you run the risk of heat sink, which transfers through to the first side and melts that lovely seam you produced, so by using 50/50 solder on the first side which has a higher melting point than 60/40, the risk is greatly reduced. After finishing the soldering to both sides, wash it in water to remove flux residue and then choose the options for finishing. You can use black patina if you want a black look followed up with lead polish, which will seal it. Copper patina for a copper look, or if you like it silver you can apply a liquid silicon type car polish to it to seal it and this can be used to seal the copper patina as well. If you don't seal it, it will always tarnish and spoil the look. Don't leave it for too long after you've patina'd it before you seal it.)
Step 2. Always use at least an 80-watt soldering iron that has a right-angle bit, as in the photo above and at right - I cannot emphasize that enough. It has the advantage of 'seeing' that the bit is at 90 degrees to the lead so that you know the bit is flat on the lead, while the element and handle is easily held parallel to your work. Until you become proficient, don't buy a higher wattage iron of 100 - 120 watts first up. The advantage of a higher wattage iron is that they have a larger diameter bit (1/2") which covers a more angled join, they also heat up more quickly, carry more residual heat allowing you to work faster, but it also makes them a little trickier to use as a first iron.
AVOID a chisel tip, because they must be held at an angle and are are harder to maintain a flat surface contact between the tip and the lead. (If you can't get an iron with a right angle bit you can get a short length of copper rod from a Plumbers Supplier, the same diameter as the chisel tip and bend it to 90 degrees. Just make sure the rod is long enough to fully insert into the element and it is a snug fit or it can burn out.) A Weller or a Robinson are good soldering irons.
If you buy a Weller there are so many to choose from with different prices, which is confusing and you need to get a quality one, (the lower priced ones are not up to the standard required) and just make sure before you buy it that the bit is removable as some types aren't. Weller as yet, do not supply a right angled bit and you will need to make one as described. I personally believe the Robinson is a far better quality iron and even though they are more expensive, they come with a right angle bit. The Robinson is Australian made and the 80-watt with a right angle bit is upwards of $100 - 116 on-line. If you buy on-line, specify it with a right angled bit as it comes with either.
If you want to buy an 80-watt Robinson soldering iron on line, you can Google where to buy a Robinson soldering iron, but to save you time in that, I found the best price is $100 from Bromac Engineering in Wagga Wagga NSW. Their phone number is 02 69 31850002 69 318500 or you can email them at email@example.com The salesman that I talked to said the easist way to buy would be to phone them and use your credit card. The soldering iron is part # 7708 - 2, which is specifically designed for leadlighting and has a right angle bit.
I need to add that I have no affiliation or association with either Bromac Engineering or Robinson soldering irons in any way, I'm just trying to steer you to a good quality iron, but you can make your own mind up.
Periodically remove and clean the oxidisation from the bit (if it’s copper) with steel wool. Failure to do this will result in the bit becoming ‘stuck’ in the element and you will never get it out when you need to replace the bit. Make a simple stand for the iron by nailing two horseshoe nails into the chipboard at the side of the leadlight to form a X. This is to hold the iron off the bench while you are waiting for it to heat up.
Step 3. When starting off with a brand new iron, or a new bit, make sure the tip of the bit is dressed then tinned at a low temperature. Dressing the tip means filing it flat. It's not necessary to dress the tip every time you are going to solder, it's only when the tip starts to get a hollow on the end of the tip, which is detrimental to good soldering, it needs to be flat to effect a good join. So never solder if the tip has a hollow of any kind, re-dress it first. (It is usually the copper tips that first get a hollow after a while, but when the nickle plating wears off some tips, it too will eventually form a hollow.) Tin the bit each time after dressing the bit, which is coating the tip with solder from a TINNING POT.
HOW TO MAKE A TINNING POT:
Only use a steel can of baked beans or similar as in the photo above, don't use an aluminium can, solder won't adhere to it. First melt some stearine flux almost up to the rim on one end of the can and melt 50 - 60mm of solder into the flux, then stir around with a hot iron until the solder adheres in a thin film all over the can end. It will take some time to heat the can - just be patient and let it cool right down and the flux has solidified before using it. It will be too hot if you try to use it before you let it cool.
Do NOT empty the contents, It's primary job is to cool the iron when you need to; an empty can will heat up quickly when you use it. The advantages of a tinning pot will become obvious as you read through this lesson and it will become your favourite piece of soldering equipment for very little cost.
Step 4. Ensure the leads are reasonably level with each other at the joins by lifting up the leaves of leads that may be folded down with a lead knife. Tidy this up during assembly or before soldering and soldering is easier.
Step 5. Thoroughly clean all the lead joins with a suitable, tooth-brush size wire brush as in either of the two photos shown above. Don’t be limp wristed but don't use a large industrial type for removing rust and mill scale, they are too savage on the lead.
Step 6. Flux each join with stearine flux. Flux is a cleaning agent. Do NOT consider using other fluxes for these reasons: Liquid flux is an acid which eats clothing and isn't kind to your skin and also dries out needing re-applying before finishing. If there are gaps in the joins, liquid flux can fall through and damage your cartoon. In some instances for specific purposes, liquid flux IS used. (When soldering zinc for reinforcing, see Lesson 8.) Cream fluxes are simply messy.
Stearine flux is the easiest to use on lead, you rub it on dry, it melts during soldering then solidifies after, making it easy to remove. You don't need an excessive amount, just enough to form a good powdery coating on the joins to be soldered. Rubbing too much on just makes more work to clean it up with the wire brush after it has solidified. Don't try to clean it up while still hot and in liquid form, you won't get it all off. Most people, after trying stearine flux, don't go back to whatever they were using because of it's simplicity.
When you buy stearine flux it is bought in a block, like soap. (See photo above.) It's too cumbersome to use like this, cut it into 'chip' size fingers or sticks as in the very first photo and it's easier to use. You should be able to get 8 flux sticks out of a block. Don't use a knife to cut it as it will crumble, use a hacksaw or tennon saw.
One supplier in Australia that I know definitely sells stearine flux is Hartley Williams and their address is 32 Kremzow Rd., Brendale 4500, Brisbane. Their phone number is 07 3881 197807 3881 1978. If you live in another country other than Australia, stearine flux may be hard to come by. I can only suggest to Google 'where to buy stearine flux' in your country.
For those in Australia, if you email firstname.lastname@example.org and buy a couple of blocks, a block costs about $4 and if you cut it the way I've suggested it will last for some time. The freight won't be much at all because it's very light - you pay freight on weight. If you plan on making a few leadlights it's probably worth getting 2 blocks.
For those living in the United States and Canada, I am told courtesy of Vic Rothman in the US, that stearine flux can be bought at: http://www.johnsonmfg.com/temp/FLUX.HTM scroll down products column and click on 'Organic Flux Sticks' and you can order it from them. He suggests to take it out of the cylindrical container and let it dry out for a while before using.
Step 7. Before soldering, test the tip on your tinning pot; as soon as the tip readily melts and puddles the solder by easily moving the tip around in an area about 15 - 20mm (1") round, you are now ready to start soldering. If you still have to force the iron through the solder, it's not quite hot enough yet.
(Because there isn't a temperature gauge on the soldering iron, there is no way to tell when the iron is hot enough to begin soldering. By testing the tip on the tinning pot it will tell you when it's ready.)
When, and only when the iron is at the correct temperature to begin soldering, apply a small amount of solder quickly over the join - NO more than 3mm for average size leads and it only takes a second or so to do this. (The solder should almost instantaneously melt under the hot iron with a 'soft feel' - if you have to forcibly chop through the solder, the iron is still not quite hot enough.) When applying solder to the join, place the solder from the roll right on the join. If you cover half the join with the solder it will likely be enough. If the join is starving for solder, you can always add more in small amounts. Your aim is to create a nice flat join for the best appearances, using too much solder will just look lumpy.
Remember to simultaneously pull the solder away from the join the moment you lift the iron otherwise the solder itself may stick to the join. Quickly touching it with the iron in the same spot should release it.
Step 8. Re-apply a small amount of flux on top of the solder. Don’t be so heavy handed that you mash the solder; just lightly and quickly touch it. Because the solder that you've applied in step 7 only 2 or 3 seconds ago is still hot, it melts the flux as you lightly touch it, putting a thin film of flux on the solder and makes step 9 go that much better. It doesn't take long to realize that flux is the magic ingredient when soldering. Try and establish a reasonably fast, constant rhythm, not so fast you are tripping over yourself, but not at snail pace either. During this step, get to know your tinning pot by keeping the iron from overheating.
Step 9. Apply more heat from the soldering iron, making the solder a liquid, heating the lead and counting 1, - 2, - 3. (That means a full 2 seconds.) It is very important to heat the lead to a point where the solder ‘blends’ with the lead and becomes one. If you try to solder too quickly in this step, which is really the same as soldering too cold because of the speed simply not heating the lead to cause the 'blend' and is called 'cold adhesion' - a poor bond will result and it may also be lumpy because the solder tends to chase the iron when you lift it off the join, simply because the bond hasn't been completed with enough heat. For a nice flat join, it must be hot. Remember to 'favour' both leads equally with the soldering iron so that both leads are being heated at the same time - don't just cover one lead only.
Sometimes when you lift the iron off the lead after completion, if you lift it too quickly OR too slowly, the solder can tend to chase the iron if it's not done at the right speed. (Just be sure that this isn't because you are trying to solder too fast/cold as mentioned above.) If this is happening when you are soldering, you know you are lifting it either too fast or too slow. Fortunately, it's a fairly wide band between too fast and too slow, so it doesn't take long to find the right speed to lift it.
It’s a very good idea to practice these last 3 steps cold before turning the iron on.
Take your time and get used to the rhythm you need to develop. There are some who are used to soldering other metals and can be surprised to find lead can melt under a very hot iron. Just remember the tinning pot!
When you practice the steps 7,8 & 9 cold, practice as if you were going to solder four or five joins in a row, not just practicing only on one, this helps to develop the rhythm. Remember to count 123 during your practice session as well, even if it's only in your mind because it's part of fitting into the rhythm. Get yourself organised with everything in easy reach. If you are right handed, you will hold the iron in that hand and the tinning pot will be nearby on your right. Your left hand will be holding the roll of solder which you will put down to pick up the flux in your left hand to do step 8 as well. You will soon realize if you keep hold of the flux 'chip' or stick between the index and middle fingers and pointing forward like an extended finger, you can still hold the roll of solder in the same hand and you are only picking up and putting down one object instead of two. If you can manage this quickly during practicing, it soon becomes second nature. Vice versa for left handers. When you have practiced enough so that your movements are fluid and doing these steps with no hesitation or mistakes, now you can turn your iron on.
You may find it easier to unroll about 250mm of solder from the roll to begin soldering. Some people prefer to hold the solder itself, others prefer to hold the roll, I like holding the roll. As you solder, this length will soon diminish and more solder will have to be unrolled. This is where you put the iron on the cross you've made from the two horseshoe nails and quickly unroll another length from the roll. So, because you've paused for a moment, cool your iron on the tinning pot for a few seconds before continuing.
THE SPEED TO SOLDER.
You will find as your experience and soldering technique improves, your 'speed' will fall into place fairly quickly to a point where you will spend less and less time cooling your iron on the tinning pot because when you are soldering at the right pace, the iron will be cooled naturally from the cold lead in the leadlight and remain at a stabilized temperature. Once you've developed the right pace, the only time you will need to 'know the tinning pot' is when you pause for whatever reason. I call this being 'ahead of the heat band'. It's only when you slow down and get behind the heat band that you need to remember your tinning pot to avoid overheating your iron.
(When I first started teaching I was surprised to find that none of the students in my classes who had learnt leadlighting before and were doing it again, mainly because they didn't have any notes and they had forgotten most things, had never heard of a tinning pot before. They were all amazed at the value of a tinning pot from that day onward. I'm even willing to bet that the majority of people reading this lesson have never heard of it either! I was also asked many times at various stages, why are you telling us all your secrets? Firstly, they are not my secrets, and even if they were I don't want to die with them, so I don't have any rights to them. Yes there are a few things that I have 'invented' myself, but the majority of these methods have been willingly passed down by professionals in the trade so that others may benefit and I am thankful for the instruction that I had, so who am I to keep things back.)
Step 10. A soldered join is not finished until it is smooth and flat. If a join is unsatisfactory let it cool a little and work it again, but don’t overdo it. Remember you've already heated the lead to a certain point. Counting 1,2 should be enough.
Step 11. When finished, vigorously wire brush off excess flux completely and vacuum clean.
Step 12. After the panel has been soldered on the first side, check and make sure all the joins have been soldered, it's easy to miss one or two; it now has to be turned over to solder the second side. If it is only small it isn’t difficult, but care needs to be employed when they get to door panel size and larger. For a door panel size, it’s the same as taking a sheet of glass off the bench, slide the panel half off and half on the bench. Rotate to vertical and turn the panel, then reverse the procedure. For a full side-lite panel, it’s best to leave it on the board it was made on. Remove two of the beads, the long one that is furthest away from you and one of the ends. With the help of another person, remove the board and leadlight off the bench and stand it in front of the bench. Just make sure as you lower it to the floor it doesn’t tilt forward. Then with the other person helping, lift the leadlight off the board, turn it around end for end so that the unsoldered side will now be face up. Place it back on the board then lift everything back up onto the bench. It is now that you discover how well you cut the leads square and butting close! If there are any serious gaps you may have to use the repair technique from the 2nd last paragraph this lesson. The mark of a good leadlighter is seen on the second side.
MAKE A TINNING POT.
NEVER solder without one; it helps to maintain a safe temperature of the soldering iron while you work. (See step 3.) It also cleans the tip each time you go there.
Try to get into a rhythm where the iron is on the job more than it is off, this keeps the iron from overheating. So don't spend too much time inspecting the join after you've compled step 9 before moving on to the next join. A quick glance will tell you if it's ok. Just remember, whenever the iron is off the job it heats up rapidly, if it isn’t on the job, keep it on the tinning pot. Your tinning pot will become your best friend when you are soldering. If you notice the solder changing from a bright silver colour to a dull grey, the iron is way too hot, quickly cool it down on the tinning pot and try to work a little faster.This colour change happens a millisecond before the lead melts! This is something you need to be aware of and be watchful for, particularly if you are soldering too slow - getting up to speed will fix the problem.
As mentioned in Lesson 2 and above, the only fumes that can be toxic are from liquid flux and you will get fumes from stearine flux, which aren't excessive or dangerous and you can disperse these fumes with a fan if it bothers you. But I found from my own experience that if you have the fan blowing directly on your work, you never seem to get a good result - so have the fan blowing above your head, not on your work and it will be ok.
In the soldering process, move the tip up and down over the join, but don’t paint, (which is moving the tip around in a rotational direction) this spreads the solder out and it forms a ‘rim’ that is difficult to flatten. The bit on an 80-watt soldering iron is wide enough to cover most lead joins individually so painting isn’t necessary.
On a T intersection you would apply the solder to this join with one 3mm amount (as in step 7) but where the joins form a X, you apply two separate 3mm amounts to either side of the 'through' lead. When soldering an acute angle with a long join, you can first put down two or more small amounts of solder then starting at the narrow end after re-fluxing, drag the iron along the join. Hold the iron at a very slight angle to the lead so it is acting like a mini bulldozer, then lifting it off smoothly at the end of the join after a very slight pause. (You can drag, but don't paint.)
Do not be tempted to use a ‘temperature controller’ - learn to use a tinning pot for temperature control because you will tend to solder too cold with a controller. (See also step 9 about soldering too cold.) A little word of caution with your tinning pot - soldering can still make some people nervous, which causes some to NOT 'get up to speed' and should be overcome in the practice session. However, if you spend too much time lingering on your tinning pot, it too will eventually become hot and NOT do it's job of cooling the iron as it should. If you can do it right in the practice session, turning your iron on shouldn't make any difference. It's ok for your tinning pot to become warm, but never hot. One way to tell if your tinning pot is only warm - the flux on the tinning pot should mostly remain in a solid form except in the spots where you have been cooling your iron. If the flux is completely in a melted and liquid state, you are spending too much time on the tinning pot, which in turn has heated the contents causing the flux to melt. Once you get to this state the tinning pot will not do it's job. When you are up to speed you will hardly have need to go on the tinning pot, because as I've already said the cold lead in the leadlight will automatically cool your iron WHEN YOUR SPEED IS RIGHT.
Sometimes blobs of solder can fall onto the glass. RESIST the temptation to pick it up with the tip of the soldering iron, as it can cause the glass to break. (Glass is tolerant of being heated up uniformly all over, but not quickly in a localised spot.) You might get away with it 9 times out of 10, but if it ever happens, you will never do it again. Simply let it cool and flick it off. Same if it falls on the lead, solder won’t adhere to the lead where there’s no flux.
If you are a first time leadlighter and have never soldered a leadlight before, and the above seems a little daunting, even though there are 12 points, there is really only 3 steps. So to simplify the actual process and break it down into the 3 steps, firstly it's placing a small amount of solder on the join, (7) then re-fluxing, (8) and lastly, applying more heat to flatten and bond the join. (9)
There is no need to panic about soldering, I've never taught anyone who couldn't master this process quickly and most people become quite proficient at soldering by the time they finish soldering the second side of the exercise panel.
The secret of good soldering, is firstly having perfect lead joins and secondly, learning heat control, which is governed by speed and the use of the tinning pot when necessary.
I cannot stress the first point in the above sentence enough as it is the building block for good soldering. Get that right and the second point comes easy. I would again advise making the simple panel described in Lesson 2. It won't cost much - you can use some scrap glass as the pieces are no larger than the palm of your hand, and it will take all of an hour or so to make. By making this simple exercise you will be much happier learning to solder correctly on this panel before you solder your pride and joy.
Please, oh please, while you are learning, remember the tinning pot!
If the worst does happen and you burn a hole in the lead, it can be fixed as follows. Firstly get the iron cooled down because that was the trouble, then very quickly fill the hole with solder. Let this cool down a bit (keeping the iron cool at the same time) and then re-apply some flux to the join. No more solder is required and instead of applying heat over the solder that filled the hole, apply heat to the lead on both sides of the hole and slightly into the hole, letting the heat dissipate into the area of the solder in the hole, which will flatten the join. Keep a close eye on this, watching for it to happen, as soon as it begins to flatten, move the iron to the other side of the join and repeat. Remember this is repair work and the best you can do IS the best you can do.
If for any reason an old leadlight has to be re-soldered in certain areas to effect a repair, first it has to be removed from the frame and placed flat on the bench - you can't solder vertically. There will be a lot of oxidisation to the joins and surrounding lead which must be totally removed before you can successfully re-solder the join. With your lead knife, scrape the surface of the lead about 10mm either side of the join until it is a bright, shiny new colour. You have to scrape deep and go well back to bare metal to remove the oxidisation. Then vigorously brush the join with a wire brush to remove as much accumulated dirt from the join as possible. If it isn't clean dirt will rise to the surface during the heating process which will only hinder the successful adherance of solder to the join. Use plenty of flux and heat. Even after cleaning as best you can it is hard to get a perfect repair.