I see the thread was locked on this original post so I would like to give my thoughts.
when I first got interested in refinishing barrels for myself, I was looking on how to refinish Damascus barrels. Dr. Gaddy had a post and i wrote to him and he sent me what he did and used. He recommended Radio Shack Etchant 15% which is Ferric Chloride, used it straight from the bottle into a 4" PVC pipe with a solvent bottom cap and a slip-on top cap filled with distilled water to a line marked on the pipe to allow a 32" barrel to fit without overflowing. I used Laurel Mountain Forge bluing and after striking the barrel finishing up with 320 grit. Dr. Gaddy said he never used any finer than 320 grit. I boiled these barrels in an aluminum tank that I made for steam bending the back posts of chair legs for was plenty long. I boiled them for ten minutes and then boiled again for 10 minutes then carded with a patch of denim from old jeans. boiled again, carded, and maybe again to see how dark they came. Took barrels and put them in tank with a string through the extension rib (L.C. Smith) for 5-8 seconds no more, rinsed thoroughly. carded again with the denim and that was usually the end. I didn't give it all that many boildings or dippings just enough to bring the pattern out

I definitely agree that 45 second dip in the solution and you would have no pattern left.

Like I stated this is from Dr. Gaddy's formula and it has been more than a few years since I have done another and like I stated, only for me.

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