Plumb Brown Barrel Finish ... fairly easy to use...
https://www.leevalley.com/en-ca/shop/tools/supplies/finishing/finishes/111231-browning-metal-finish
Hey Guntech, I like BC plum brown, but have never tried it on a Damascus barrel. Does it show any pattern right off? Or do you etch it with ferric chloride or something afterwards?
I read some comments on a black powder forum that said the BC Plum Brown was great for small parts but went on uneven on barrels. Have no experience with it just what I've read.
the formulas in Angier's book on browning and bluing as well as in Foxfire 5 both use mercuric chloride as the principle rusting agent and alternate with ferric chloride solution plus hot water between stages and carding to bring out the pattern. You will also find a detailed description in a couple of old Double Gun Journal articles by Oscar Gaddy (now deceased.
the major problem is obtaining mercuric chloride although you need very little of it, in part because it dissolves in water poorly. I don't do the work commercially and don't sell the chemicals but I have done a number of damascus barrels; the results vary from barrel to barrel and the fancy figure 8 patterns are the hardest to bring out without browning everything.
cheers mooncoon