Guns+welding

[xandi]

What kind of welding is done on guns? Repair and during manufacture? And why?

[Nathan]

Usually TIG.

To add metal for fitting or to combine machined parts when forming from a forged or cast part is unreasonable. Like the barrel lug on a custom t/c barrel. Barrel blanks are round. Messing with that can negatively affect accuracy.

[dahermit]

TIG = Tungsten Inert Gas.
MIG = Metal Inert Gas also known as Wire Welding.
In case anyone did not know.

At one time it was common for gunsmiths to modify Mauser and other military straight-bolt actions by cutting off the bolts and welding on bent bolt handles.

Also upon occasion, they would cut and weld square butt Smith Wesson revolvers to modify them to a round butt configuration.

[xandi]

Would you have to re heat treat the barrel and other parts afterwards?

[FrankenMauser]

TiG is most commonly used by professionals; and TiG (GTAW) or MiG (GMAW) during manufacturing - such as welding the barrel lug to H&R single-shot barrels.

Bubbas in their shed often ruin a good gun by pulling out the MiG, SMAW (arc), or oxy-acetylene rig to fill holes or weld broken tangs back on receivers; and getting too much heat in the part (or localized area).

Would you have to re heat treat the barrel and other parts afterwards?

It depends upon the function of the part.
Receivers, some bolt parts, and certain other parts - yes.
Non-critical parts and barrels - generally, no.
Some parts are only case-hardened or only need to be hardened in certain areas. A Mauser-style bolt, for example, can have a bolt handle welded on without the need to re-harden the part as long as measures are taken to prevent the locking lugs and cocking cam from getting too much heat.

[Jim Watson]

Yah, they make heat sinks and heat control pastes for such work.

I think TC attaches underlugs to round barrels by electron beam welding.
There is some use of laser welding in fine applications.

[xandi]

Guess this means I want a tig capable machine thx
How are muzzle devices welded on?btw

[dakota.potts]

In the military parts kit rebuilding community, all types of welding are common to take a torch cut receiver and weld it back together (TIG, MIG, some people even using wire feed). Think Sten, Uzi, H&K roller locks, ppsh41/pps43, Sterling, Suomi, pretty much any surplus parts kits that are imported to the US that people have found a way to rebuild.

Any Oxy/acetylene rig is useful for brazing and soldering parts such as barrel ribs on shotguns or sights on barrels.

It is typically not extensive welding done on guns themselves. I have done a bolt handle as mentioned. I have seen a couple of beavertails TIGed onto small handguns to extend a grip. I once saw an angle plate welded to the bottom metal of a rifle for use as a barricade rest in PRS competition.

I have been told that MIG is preferable for welding on muzzle devices due to the lower heat but I have never done this myself so I don't know. High temp silver solder (1400*) can be used as well =.

[reynolds357]

Just out of curiosity, why are you welding on muzzle devices? I have done it only one time and it was to make a muzzle brake non removable and thus make a 14" barrel legal. Is there another reason to weld on a device?

[Nathan]

IMO, I would not weld on any gun without TIG. TIG is much more localized. MIG and most everything else will over heat and stress/warp the gun.

Think of it this way. If I heat the whole part welding hot, it is all liquid and becomes a puddle. It I heat just the smallest area to mix base metal and filler, most of the rest of the gun does not get hot enough to change shape. Therefore, the heat affected zone is minimized and the base material properties are left in tact.

[Mobuck]

I've MIG welded several bolt handles. Those adjustment knobs are there for a reason.

[jmorris]

I use TIG unless I am applying silver solder then it’s oxy/act.

[4V50 Gary]

It was asked about heat treatment on a barrel. I wouldn't weld on a barrel. I can see silver soldering but not welding.

[Scorch]

Pretty much a given that if you weld on a barrel you will have a tight spot in the bore. Use TIG and mild steel to fill screw holes on the action if you want, but not the barrel.

[tobnpr]

Disclaimer...not a Certified welder (but know one).
Not the case that MIG has a larger HAZ than TIG. DC TIG, being slower inputs more heat into the part than short circuit transfer MIG.

So I've been told... there seems to be this mentality of lumping a cheap Chinese flux core machine in with all MIG welders, as though MIG is a red-headed stepchild capable of only half-azzed jobs on trailer in a field somewhere.

I luv my Lincoln MIG...

[xandi]

So if I wanted to say repair the worn out internal rails one of those old semiauto hunting rifles I would have to machine then surface hardened the receave right?

[Scorch]

So if I wanted to say repair the worn out internal rails one of those old semiauto hunting rifles

Here's how you put the best parts of a 740 or 742 that the rails have worn out on back into service:
* Using a #1 straight-bladed screwdriver, remove the front and rear sights.
* Set them aside, discard the rest.
* Get a 740 or 742 that works well (if there is such a thing) and attach the sights.
Done!

All sarcasm aside, unless you want to dedicate your life to machining and welding and machining and welding and machining and welding, give it up. There are newer versions of those guns. Get one of them.

[RickB]

I had a "microwelding" repair done by a business called Pullman Arms, in Massachusetts.

[xandi]

Oh and you can use a different shielding gas for less heat transfer to the base metal like He/Ar

[80viking]

I know those guys (Pullman) and have watched them weld with I think it was a microscope hooked up to a monitor. They can do some amazing things with metal and are a very specialized nitch business.

More on topic, I have mig welded my share of mauser bolts with the appropriate heat settings and heat sinks.

[jmorris]

All the Contender lugs are welded on the barrels, lots of others too. Not uncommon at all on single shot rifles.

A number of ways to absorb excess heat.

[Bill DeShivs]

I have a jeweler friend who has a very expensive laser welder. We weld tiny pieces of steel often. It has been a great help in my knife restoration business.
The heat is entirely localized. He can weld a ring while holding it in his hands.
If I were a younger man, I would buy one ($25K) and set myself up to do precision welding.
You can retip a firing pin, weld up a dinged rimfire chamber, etc.-while holding it.

[xandi]

Bill DeShivs, thx that’s the kind of kind of stuff I was wondering
Can you add filler material with that Laser welder?

[disseminator]

I would always lean towards the TIG process for gun parts myself.

You just have more control with the TIG and it can really be dialed down as slow as you want which is useful for precision work.

[Bill DeShivs]

xandi- yes, you can- but it's slow, of course.