What Gun Owners Need to Know About TIG Welding
October 21, 2010
Just TIG it up. That statement can have the same effect on me as running your fingernail across a chalkboard...
Just TIG it up. That statement can have the same effect on me as running your fingernail across a chalkboard. I cringe whenever I hear someone invoke those four little words. It isn't that I have problems with TIG welding. Lord no! As a gunsmith I've come to really appreciate TIG and the things it'll enable me to do. I cannot imagine being without it. My problem is the misunderstanding and lack of basic welding knowledge of so many folks that invoke those four little words. Many of these folks, bless their hearts, have truly unrealistic expectations as to what a gunsmith can do with TIG. I sometimes think they view TIG as a magic wand that a gunsmith can wave over any gun problem and immediately fix it. Unfortunately, that just isn't the case.
Let's take a look at TIG, what's involved, what it can and can't do, and how TIG can be used in a small shop or by the hobbyist. Even if you don't weld and have no desire to learn to weld, the more you know about the process, the better prepared you'll be to discuss welding projects with your gunsmith. Then again, once you learn more about TIG, you just may want to get more involved. If you're already set up to do welding, either oxyacetylene or arc, you might want to consider adding TIG.
The process was developed during World War II in the manufacturing of aircraft, and for many years it was limited to large industrial applications. It was only in the 1960s or so that the equipment was developed to the point that it became practical and economical for smaller shops. Since it's basically an electronic process, like all things electronic, the price and size of the equipment has been dramatically reduced over the years. TIG equipment is now available at prices that most hobbyists can afford. And an equally important factor for the hobbyist is that you no longer have to have special wiring or power supply. You can literally plug some TIG outfits into a regular electrical socket and go to it.
TIG stands for tungsten inert gas, and that's how most folks refer to the process. However, that's not technically correct. The technically appropriate term is GTAW, which stands for gas tungsten-arc weld. However, I grew up with the old terminology and will keep on usin' it.
TIG is especially helpful in making a difficult repair when the parts are very small and thin, as on this broken Walther PP safety. Whereas solder would not hold the parts together satisfactorily,
TIG is a form of electric arc welding. An electrical current is directed from the power source through a hand piece that holds a tungsten electrode. The work piece is grounded and connected to the power source as well. When the hand piece with the electrode is placed close to the work piece, an electric arc is formed. The arc is what does the work. It creates a tremendous amount of concentrated heat, and this concentration of electrical energy melts the steel under the electrode.
TIG rejoined the parts, and the pistol was quickly back in service.
What is unique is the utilization of argon gas to envelope, or shield, the arc and the point where it contacts the work piece. The argon gas, which is inert, blocks the molten steel from oxygen in the atmosphere. This prevents the burning of the carbon present in the molten steel. This has always been a problem with older methods of welding such as oxyacetylene. Have you ever seen a bolt handle that has been welded on an old Mauser or Springfield and noticed some tiny pinholes in the weld? That's the result of the carbon in the steel being burned out. The argon gas helps to eliminate this problem.
Note that I said helps to eliminate this problem; I didn't say that it totally prevents it. Pinholes can develop in a number of ways, and this is one of the major misunderstandings of the TIG process. TIG will not guarantee perfect welds! In fact, TIG is one of the most difficult types of welding to master. It's not impossible, of course, but it does take a lot of practice and experience to do it well.
Another major advantage of TIG is that you can control the heat of your arc by limiting the amperage. Most TIG welding machines have a dial or control to allow you to precisely set the amperage. In addition, the person doing the welding can use a foot control or rheostat on the hand piece to provide additional control over the amperage. All of this just means that you have much more control over the heat and intensity of the weld. You won't find this in other older welding processes. This is especially important when repairing or building up small parts where excessive heat could literally melt the entire part you're working on.
A major misunderstanding I've often encountered relates to pitting. Many folks think that you can easily TIG up pits. Sometimes you can and sometimes you can't. The problem with pits is that you must remove all oxidation or rust before you can weld the pit. On large, shallow pits that may not be a problem, but on narrow, deep pits that can be virtually impossible.
If you don't remove all the oxidation before welding, it will create voids or bubbles down inside the weld. These will often show up as tiny pinholes. If you then try to weld up these pinholes, you'll create more pinholes. You can chase pinholes all over your weld and never get rid of 'em. Again, welding up pits is not as straightforward, certain, or as easy as you might have been told.
Due to the intense heat and light created by the TIG's electric arc, you must wear a full face mask and gloves.
TIG welding can be a tremendous aid to the gunsmith even though it takes a lot of practice and experience to even begin to utilize its full potential. Just keep that in mind when you hear someone say, "Just TIG it up." Remember it's not magic, and it won't solve every problem.
Until next time, good luck and good gunsmithing!