doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Welding cracks in barrel tubes?

I have a Lefever DS 16ga that has a crack in one of the tubes. The crack is linear and at 11" from the muzzle, 15" from the breach. Is this something micro-welding can fix?

[img]https://photos.app.goo.gl/bCkgAV5LthAV92Ri6[/img]

[img]https://photos.app.goo.gl/14TRRNmnMCaZU3dj6[/img]

15” from the breech is pretty close to where your front hand would be if the repair fails.

That looks like it already blew out once, and somebody hammered it back down flat.

Myself, I think the split could be welded successfully. But the other damage I don’t think so.

A good weld on that tube would be stronger than the tube, but again, it looks like it already blew out once, and then somebody hammered it down flat

When I first saw the crack I thought there had been a bulge at that point in the barrel, but there is no sign that a bulge was ever present. No ring is observed when looking through the bore. There is a dent that has been mostly pushed back out with the crack running through it. When I get time I will measure the wall thickness at and around the damaged area. If the wall thickness is thinner near the crack then a repair will not be attempted. Thanks for the replies.

Ask yourself how much you value your fingers ? There looks to be much larger area of concern than just the crack . In times past people have soldered patches over damage like this and that in MHO would be better than welding even with modern welding techniques . Others may disagree but want you do is your decision and risk .

Weld it and proof it a few times.
Thank about it, there were literally children working with their fathers to hammer weld laminate barrels over charcoal forges, and they created works of art.

You can weld the tube. But! To reiterate, just looking at the pictures, there was damage there, and seemingly a blow out.
It’s probably struck tissue thin there in an effort to repair the original dent/bulge, and then it split shortly after.

Get measuring. See it you can have it UT tested as well.

My guess would be that they over honed/struck out the original repair.

Edited to add:
Which is a shame.
Bulges never seem to be repairable.

How thick is it and why did it split?

Is there a crack perpendicular to the linear one , near the middle of the linear one?

I believe the perpendicular defect is the original crease/dent



I've done an analysis of a c. 1912 Lefever Arms Co. DS “Dura Nitro Steel” and it was non-standard AISI 1035 with a measured tensile strength of 91,500 psi. Comparable to most of the c. 19teens - 30s U.S. double's fluid steel barrels.

This is a Model 12 Winchester Proof Steel barrel with a similar split; hard to tell from the pic but it also was probably where a dent was raised



Pressures at 15" with today's fast burning shotgun powders are about 1000 psi



Please let us know the wall thickness at that location

If the wall thickness is .020" and it is subjected to 1000 psi internal barrel pressure, it will have a hoop stress of approximately 18,000 psi. Since 1035 has a yield strength of ~40-50k psi, this is over 2:1 safety factor. So, welding it with a mild steel rod and striking it down to .020" should be more than adequate. Although a matching alloy could be used, my experience is that a lower carbon steel rod helps prevent a concentration of excess carbon and cracking along the edge of the weld. I have made copper plugs that fit the bore well, then TIG welded barrels successfully.

I recall Dr Oscar Gaddy shared with me that he had successfully TIG welded a damascus barrel at one time.

From what I see there in the picture, I would investigate further to determine if those are small cracks running radially. If so, I'd weld those, possibly in a radial weld bead.