doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com TIG welding

Can someone explain to this old dinosaur just what TIG welding is? I've heard it can be used to fill pits on the exterior of barrels, frames, etc. Doesn't the heat required cause metal distortion? I've heard the term bandied about but really have no idea of what is involved in the process. Thanks loads! Chopperlump

TIG means tungston inert gas, you hand feed the filler metal into the arc which is under a shield of argon gas. The arc comes from a sharpened tungston electrode A real picky welder will mix 5% hydrogen with his argon so it will burn any oxygen leaking into the shielded area. In industry parts are often simply fused together without filler. The heat affected area can be quite small.
bill

What are the bluing properties/characteristics of the welded areas?

I'll show my ignorance here as well concerning the tig welding of pitted barrels and actions! Does the size of the pit matter? Is a small bead put in each individual pit, or is a bead layed on over the exterior of the pitted area and then filed down to match the contour of the barrel?

I just can't visualize in my mind's eye!
Thanks

Cam,
Generally, each pit is welded up individually. The surface should be clean and free of rust or any guck. Chemical cleaning and/or mechanical is used to either etch rust/corrosion or grinding with a rotary burr to remove any potential contaminants. Once welded up a barrel, I normalize the weld and the adjacent area by heating with a welding torch since I've encountered hard spots directly adjacent to the welding on some barrels. Then filing can be done without any difficulty.

Any clue as to the blue aspect? I've heard that rust blue will show the tig(ed) areas... Anyone tried rust blue after weld build-up?

The bluing properties would depend on a careful match of base metal (barrel, action, etc.) and filler rod. Hard spots would depend on how the base metal alloy reacted to the heat of the welding. Since pits are generally small (both size and volume), the amount of heat and hot metal is small relative to the size, shape, and volume of the base piece. So, this work can be generally done without warpage. The "smallness" of what can be done is pretty amazing. BTW, I predict a pretty good market for the first guys that do good barrel bore pit filling.

sometimes hot blue shows the different metal, but rust blue is usualy the same color across the board.

TIG allows you to do very precise welding and not use an obscene amount of heat on the part. You have more finesse with a TIG rig than any other kind of welding, so you can do things such as weld individual pits, weld 2 razor blades together, and other very detailed work.

I use pure argon, as does every other custom maker with whom I have spoken. Also use 1/16" 2% thorinated tungsten and 1/16" filler rod of various alloy. I also use a foot control rheostat for the amperage. You can weld with as little as about 5amps of current. This allows you to add just enough heat to the part to get the puddle and fusion you need, but no more.

Another benefit is that welds are very "clean," assuming you haev done everything correctly. This is critical when doing highly finished custom work.

TIG has replaced oxy/acetalene welding in gun work just as forge welding was replaced many, many years ago.

On the barrels I welded, apparently they had enough carbon to harden when the weld 'self-quenched', a characteristic of TIG welding.

Chopper

Here is some good info how to weld with TIG
http://www.millerwelds.com/education/tech_tips/TIG_tips/hints_tips.html
Casey