Welding Tips and Tricks

I have a shotgun barrel that I believe to be 1137 mild steel but i am unsure. I need to weld up some stamped lettering on the top. I am a relatively new welder and was hoping for anything I should look out for. I need to use 3% nickel rod because it takes rust bluing in a similar way to base metal. The letters are about 1/8 inch tall. I can either get .045 or .094 rod, which should I get? Thanks for the help guys!

I would not weld on a barrel unless it was permanently made unusable first.
The Sulphur content could hinder welding.

I agree. I can't think of a good reason to weld letters on a functional gun barrel.

Yeah, I wouldn't do that, any deform in the barrel could be catastrophic.

I wouldn't weld on the side of a cylinder well for a piston.

Just ain't worth the risk. Grind it off or something, bondo it, don't weld it.

It will not be a pressure bearing component. The barrel is cut off directly in from of the chamber (and the welded on barrel lug) and is then bored out and threaded. A new barrel of different caliber is threaded in. It is purely cosmetic, even if it wasn't the lug is already welded on. ( H&r/NEF topper)

So it won't be firing any shells or slugs?

Not actually used as a shotgun?

Very few parts of a gun are purely cosmetic. The pressure wave of firing a shot is extremely different than the pressure that pipe under static, hydronic, or pneumatics pressure sees. The response is drastically different as well. Is the lettering something that could be brazed on?

Why don't you check with a gunsmith? He'll set you straight in a minute. We're just guessing - we don't know the material, the location on the gun, if the gun is to fired again, etc.

A picture would help clarify & while I agree entirely with the negative comments based on heat treatment / strength etc when fired I don't see why in this case the OP should'nt weld on the barrel - as I read his question he is saying the barrel is sawn off ( don't tell the ATF ! ) & a new barrel fitted as a sleeve within it so is likely a smaller caliber ( though probably rifle ? ) as long as the new barrel is proofed for the load it will see then the threaded part into the old barrel only holds it in ( something like the interchangeable barrels on a Thomson Contender ? ) & moderate heating as a result of the cosmetic weld should not affect the overall strength of the action so as long as he does'nt plan on rechambering to 50 cal or something crazy it should work - on a welding note I would use the thinnest rod available & the suggestion of braze won't work for him as he states he needs to re-black it afterwards - once completed my scientific SWL test is load something to produce a pressure in the region of 50% more than any factory load then test fire it tied to a tree using a long string on the trigger for safety firing from a good distance away - if all goes well then I'd be happy to use it personally - but that's just me ! you may value life higher so choose accordingly.

i think whats been done is its been relined.
trouble is it depends a lot on what the new cal is and how its been done. because the old barrel can still be structural part.
the liner works with the barrel to provide the strength. also how its been done. heat from welding can cause separation of the liner and barrel. it really does depend on application.
a gun smith will tell you in 5 min if your barking up the wrong tree.