doublegunshop.com - home Forums General Discussion DoubleGun FAQ @ doublegunshop.com Damascus barrels and magnafluxing question

What is magnafluxing? Is magnafluxing nessessary to confirm the condition of damascus barrels (1890s Greener with nitro proof marks not marked in tons) and if so, where can you send a gun to have damascus barrels magnafluxed?

http://www.domson.ca/Technical_Articles/FAQ_MPI.htm
HTH :>) Bob.

In reality, is it necessary to go beyond a close examination of a set of Damascus barrels for pits and wall thickness? I would think that if those two aspects were in order that the high-tech approach (I don't even know what it is) would be superfluous. Just MHO.

IMHO . as Gil said - if it looks good , shoot it - paul

I have a twist bbl which I "Know" has about a ¼" long crack following the twist. Knowing where it is I can only find it with the aid of a magnifing glass. Anyone who didn't know it was there would never find it from a visual inspection. I have no idea if magna-flux would work on it or not. I would presume if properly set up by a knowledable operator it would. Possibly dye penertrant & a black light would also find it.

Magnifluxing (MT) and dye penetrant testing (PT) are surface examinations versas radiography (RT) and Ultrasonic Testing (UT) which are volumetric tests. Surface exminations look for pits and cracks. MT has some slight subsurface capabilties. Because a Damascus barrel is pattern wleded and one can readily see the welds, both MT and PT would be useless for surface examination. Becuase the welds extend throughout the material, volumetric testing will also not work. This is precisely the problem with Damascus barrels. One cannot determine by any method if a pit or crack exists. -Dick

Dick; The magna-fluxing I am familar with worked by applying a magnetic field to opposite ends of the part. A crack causes opposite poles to form at the crack & the dye (magnetic) to concentrate there. This would of course not work on an internal flaw, which I assume is what you were referring to. The one I referred to in my bbl goes completely through the wall. It seems to me this is the type of flaw magna-flux detects.

I'd think that magnafluxing would show a perfect Damascus barrel to be FULL of flaws that are not really there. JL

The problem is that MT or PT would not only find your flaw but would find the surface welds of a Damascus barrel. MT uses a ferrous powder and then it is wiped off. The powder stays in the crack and is visable upon magnetization. PT uses a red dye that seaks cracks. The red die is then removed from the surface but stays in the crack. A white developer is then sprayed onto the surface and the red in the crack shows. Radiography (RT) might show the crack if is was much larger than the welds in the barrel but with a defect that big, you would not need any form of NDE to find it. -Dick

Dick; I worked as a machinist for 35 yrs & have been around both processes, but never saw a damascus or twist bbl checked. I know where this crack is, but it is not open & definately not evident. I doubt many could find it even if told it was there. My thinking was that even if the MT process picks up on the welds, this spot would stand out much more prominent, but I could be wrong. Not trying to be argumental, incidently, but to discuss what will & will not work.