doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Thoughts on TIG welding on a barrel

I have welded LC Smith barrels. My barrels contained enough carbon that the weld heat affected zone hardened as it self quenched from the barrels being room temp. This weld was accomplished using low carbon steel rod, which I recommend for this repair. It was then annealed by torch. I think you could use a 4130 rod as well. It would need to be annealed as well. Close inspection for cracks should be made after welding and after filing the weld down. I would even go so far as to use a magnaflux or dye penetrant inspection.

And Keith's recommendations sound right on...copper backer, purge.

Correct me if I'm wrong, but to my understanding, high pressure tube and pipe are welded as SOP in a number of industries. So, with proper tools and technique, why not gun barrels?

Don,
The only concern I have is that the alloys are unidentified. I ended up chasing cracks. I wondered if the alloy used for the barrels was "unweldable" alloy that contained lead (Pb) to make it more machineable, as is common in machined parts that won't get welded. It could have also been that it had high sulphur and not enough manganese to offset the sulphur negative effect on welding (cracking).

Chuck, thanks for your information. I wasn't sure what the barrels were made of. I know the frames were low carbon steel. Since I was not a certified welder, but went through the training and can weld, I never used TIG, and this job I would not do myself.

In the power plant I worked, all of our welders were certified, and yes they did weld high pressure boilder tubes and most of our welds were either magna-fluxed and some were also x-rayed. They also used the dye penetrant on some welds but mainly to see if there were cracks before.

When the fellow first posted his friends dilemma, I thought that it could be welded if the conditions were right.

Well, we do know that there are plenty of unweldable alloys. I suppose some barrels could be such. This finding, however, begs the question of how seamless barrel sleeving is TIGed. Seems to me there must be a way. Also, I wonder if laser microwelding might do away with some of the heating problems??

DDA

The gentleman got back to me and said you can see the cut from the inside and that the cut is 13" from the breech.

It would be great if you could recover the hacksaw shavings. There might be enough for a metallurgist to analyze. I was wondering about laser welding too, but I'm not at all familiar with the process. Laser might limit the heat affected area, but you can't escape the fact that both base metal and filler must reach the melting point of steel to achieve fusion. I'm not sure how you'd accomplish torch annealing on intact double barrels since you'd have to get the welded area up to critical temperature. That might be difficult to do if you had the unwelded barrel and ribs under water to avoid melting the solder. Perhaps you could preheat the copper backer rod to just below solder melting point and play a torch over the weld for a bit right after welding in order to slow down the air cooling quench effect. Just tossing some ideas out. It would be nice to save the gun even if it isn't a super high dollar item. I sure hope the kid that did this has to make full restitution for repair or replacement. I really figured the cut would be at 9 or 10 inches from the breech and all bets would be off. There may be reason to hope here.

I've been searching for years for 20 or 16 gauge dolls head barrels for a nice G grade Lefever that suffered the same fate. There is only about .004" difference in breech width between the 20 and 16 gauge, so I'm not even sure what the gun was originally. I have the action and forearm, but the Police Dept. that sold the parts would not release the 10 inch barrels nor the buttstock that had been cut at the pistol grip.

I just saw Davids' last post that says the cut went all the way through and is only 13" from the breech. That's a bit scarier than 16"-18". But if I still had access to a TIG welder, I'd still want to try it just to see if it could work. Anyone know what average barrel pressure might be at 13"?

I am assuming that there are people out there experienced in welding barrels, as barrels are sleeved? Not the same I know as welding a hacksawed barrel, but barrels are quit safely monoblocked at times.This is not a statement on how safe the cut barrel would be after welding, simply thinking that some of the Smiths that have sleeved a barrel might provide information on the process for welding of barrels.

I did.