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SOLDERING GUNS. LEARN HOW TO USE THEM.
SOLDERING GUNS. LEARN HOW TO USE THEM
The ability to use a soldering gun or “pencil iron” soldering tool can be extremely useful in anyone’s lifetime. You’ll be able to fix endless broken devices that would otherwise require a professional electronics repairman. You’ll also be able to build your own devices from kits or otherwise, and you’ll be saving a lot of money and frustration by not having to replace broken devices. People that don't solder will love you as well as they will eventually flock to your door with broken devices seeking your expertise. In my electronics career, I’ve made well over a million or more solder connections so listen up.
First you’re going to have to buy the following if you don’t already have one or more of these tools.
1…A soldering gun (see pic). Weller is a popular brand. Around 30 dollars. Get a couple extra tips while you’re at it.
2…A pencil iron (see pic) and optional stand, Weller again. Around 15 to 20 dollars.
3…A can of electronic, water base, solder flux, (not plumbing flux) 3 dollars.
4…A pair of small diagonal wire cutters, snips, or dykes. 3 to 15 dollars.
5…A 1 pound roll or smaller amount of very thin, electronic solder (not plumbing solder). 3 to 15 dollars.
6…A small kitchen sponge.
You will be able to buy all these tools at your local Radio Shack including the sponge that usually comes with a solder station for your irons but you don’t really need a solder station unless you’re going to be using your new irons daily. Some Radio Shack tools will be way cheaper than say top of the line stuff from Home Depot. You can always upgrade brands at a later date.
Now you’re ready to rock and roll your way into the electronics repair history book but not so fast Bubba! Successfully soldering anything from two wires, to a broken radio antenna, or a bad pc board connection absolutely requires some basic how-to knowledge. Try it on your own and you’ll most likely destroy the piece you’re working on.
Lesson #1… What solders and what doesn’t solder?
First, make sure the item your about to solder is small in bulk such as a few wires, a pc board, or component connection. If the item is too bulky with too much mass, your irons will not be able to heat them up enough to accept solder.
Make very sure, whatever it is you’re going to solder is super clean. That is; free from rust, corrosion, paint, grease, oil, or anything else. Just pure, clean metal is what you’re looking for.
Electronic solder in general, will not adhere to chrome, iron, steel, stainless steel, pot metal and some others so make sure you’re working with copper, brass, bronze, silver, gold, nickel, zinc, and other non-ferric metals. 99% of all your solder connections will be copper to copper so not to worry.
Lesson #2…Flux; what is it?
Flux is a metal cleaner that ranges from highly corrosive acid types for plumbing and other industrial applications to passive, water soluble electronic flux. Not too many years ago electronic flux was not water soluble and contained tree rosin and some other nasty chemicals. If you have any of that, dump it and buy a can of the new water soluble type. Some solder is manufactured with flux imbedded within a hollow core. You’re still going to need your new can of flux as this type of solder doesn’t hurt but it’s never sufficient to make a clean, flowing connection.
When you heat any metal that’s as clean as you can get it, it will instantly produce a thin, invisible film of corrosion or tarnish that will prevent your solder from blending onto the metal no matter how hard you try. Your solder flux prevents that from happening provided you keep fresh flux on the connection and your iron tip as well which will crud up just as fast and prevent a good thermal connection to the pieces you’re soldering. Stick the iron tip right in the flux can for a second just before you make the solder connection. And when, not if, you need to, sand or file your iron tips flat or round again after the tip get crudded up. A good thermal transfer is essential.
Lesson #3. Tinning; what is it?
Tinning is the process of applying a fine coating of solder placed on the pieces to be soldered and on the soldering iron tip before the connection is attempted. On occasion, three or four wires will have to be connected to a heat sensitive pc board copper strip. Too much heat for too long and you’ll lift the copper strip right off the board. This is a pc board disaster. To prevent that from happening, you must make a fast connection in order to limit the heat flow into the board or solid state component that may be destroyed as well. With the wires twisted and tinned, and the pc board copper tinned, all you have to do is get both the connections to the proper temperature and the pre-tinning on each will easily connect the two without worrying about the solder free flowing on the bare copper or the twisted mass of the bare wires. Much less heat is required so there’s less chance of overheating the connection let alone mucking it up with too much solder or simply making a bad connection. Always pre-tin your iron and your connection if you can but be careful to shake, or wipe off the excess solder with your damp sponge before making the connection.Too much solder especially on a pc board can cause blobbing over to one or many adjacent pc strips and that’s not so easy to clean off without damaging the board. If this should happen to you, quickly reheat the blobbed solder and most of it will stick to your iron which you then shake, or wipe off and go back for more till the board is clean with no solder shorts. There are other ways of removing unwanted solder such as sucking it up with a braided piece of fluxed ground wire or vacuuming it up with a special tool available at Radio Shack as well but I wouldn’t worry about that right now.
Lesson #5. What’s the difference between a soldering gun and a soldering iron?
Not a hell of a lot other than the physical characteristics and the heat output. A solder “gun” is a high output, general purpose device with a pretty large working tip, while a pencil iron’s heat output is much less and sports a fine chisel or pointed tip for very small joints and hard to get at places. If your repairing a pc board with very fine copper strips, a clunker gun won’t do at all. They are way too big and get way too hot so switch over to your pencil iron. Even then, you may have to keep a wet sponge close by for an occasional wipe just to keep the temperature under control because the pencil iron stays hot all the time. One of the main differences is when you unknowingly go up against it with a wire, your coffee cup or anything else and not know it till you smell the smoke. Picking it up by the wrong end or leaning on it will encourage successive cuss words for at least a few minutes straight while sometimes even jumping around the room in a new and unique dance style. I’ve named my style; “GODDDDDD DAMMMMNNNN!! STUPID SHIIIIIIIIIITT, DAMNIT… ARGGGGHHH!!!.” Better come up with a name for yours up front. You’ll be there…guaranteed sooner or later.
LESSON #6. The Connection.
Assuming you’ve pre-tinned everything and you’re about ready to make a connection, first make sure your work device is secure with a c-clamp, rubber band or whatever it takes to keep you from pushing it all over your work area. Place a small blob of flux directly on the pc board, or other “soon to be one” connection and pull the trigger on your gun. Hold it for a second until you see smoke coming off the tip. Quickly dip the tip in flux, align your pieces and gently press them together with the iron tip. If one has more mass than the other, keep the iron tip mostly on it as it will transfer its heat to the connection with less mass. If they are about the same in mass, try to touch them both with the iron tip while pressing gently.
It is very important you monitor the flow of solder, you may have to call up the use of your third hand to add a bit more solder. That can be a little difficult with a gun in one hand and your wires in the other. I’ve stretched out a piece of solder many times before and held it with my teeth while adding a bit more solder to the connection. As I said before, too much solder is just as bad as too little. Only use enough to evenly flow in and between all the crevices in the twisted wires if there are any and on to the other connection. Never bury everything in a big blob.
After you’ve managed to make the connection, it’s extremely important you stop breathing for the next few seconds. Do not move a muscle until the connection has solidified or you’ll have to start all over again. This time with a mucked up connection and overheated parts. Wire insulation will melt and curl itself back, your flux will be gone and need replenishing, and by the time you’ve redone the connection, you’ll probably have an ugly mess that may not even work. A well done connection will have a very shiney look as opposed to a dull connection that was moving as it solidified.
LESSON #7. A few tips of the trade.
In the long run, we make solder connections not only to physically connect components, but to provide a resistance free component to component connection. Whether it is two wires we tape up after soldering, a transistor lead on a pc board, or a broken telescoping antenna on a portable radio. In most cases, a resistance free electrical connection is the paramount goal. Keep that in mind and learn to make a clean, shiney, blobless connection.
Holding parts together while you attempt to solder them can be pain in the butt. A couple of surgical, locking hemostats can be a tremendous helper as are simple alligator clips or should I say “roach clips” for you younger, more worldly types.
Once again, safety is a major concern here. Always be careful when working with hot irons for obvious reasons and reasons we tend not to foresee such as a small child getting severely burned from an iron you left on and perhaps left the room for a minute to get a soda.
Fire is always a concern. The irons won’t burn themselves but something they happen to touch up against on your workbench may.
And as always, never forget that these hand held devices are powered by 120 volts AC that can kill you in a New York minute if you happened to come across a frayed or burned hot wire in the cord while touching ground somewhere else or vice versa.
Unplug the power cord or remove the batteries from anything you’re working on before you start and for those of you that happened to have attended a religious school for any length of time, never, ever take these irons in the bathtub with you, at the very least while they’re plugged in.
Go back and read some Hub Page chapter excerpts from my book “Up One Level”. You’ll get my drift…