Checking for cracks

[Drew Hause]

My compliments for doing your due diligence John. I'm not aware of any NDT lab with significance experience in evaluating pattern welded barrels, and suspect it may be related to liability concerns.
It is my not particularly informed opinion that direct visualization, RT and MPI are complimentary. If MPI showed an indicator at the same location as the visible "crack" I would be apprehensive.

This is Jay Oliver's 1874 $100 grade Lifter with a fracture in the Crolle barrel probably at the rod edge "zipper" weld



A Twist fracture



Damascus-Twist fracture

[edgarspencer]

Having more years, than I care to recall, with hands on experience, in MT (dry or fluorescent), RT, LP(V), LP(F) ET, and UT, I can say that if I were heading off to a Lab (many of which are run by my ex QC Dept, I would be asking for either Visible Dye penetrant, or fluorescent dye penetrant testing.
The very nature of Twist, Laminated, or Damascus materials is very conducive to false positive interpretation. The magnetic permeability of the dissimilar materials is distinct enough to show flux field lines.


The only important part of the above, for the non techs, is highlighted. I just can't help myself.