Damascus(above) refers to Swiss Black which I agree. There are two of these formulas and I like the one with alcohol in lieu of acid. This is the exact same formula that Willi Barthold uses in his now classic (German language) textbook on gunmaking.

I agree with Damascus, PA24, and SKB as each has important points that I have also found to be true. Short rust times are very important, proper preparation is very important, carding methods are very important. I clean and degrease with full strength "Purple Power" Industrial strength cleaner between each coating--it only take 10 minutes to do this and you will be amazed at the results over what you have done before. When I have done the last carding of however many I do (usually more than 10) I clean with Purple Power and dry before oiling. When cleaning with Purple Power or any other cleaner, rinse in cold running water. Do not under any circumstances use hot water--the barrels will rust before your have walked back to you shop from your cleaning area.

With Swiss Black formula 4.5 minutes of boiling in distilled water--max for me. Over boil and you have trouble with rusting.

Make propane gas]burner that will put out so much heat (BTU'S) that you can raise 3 gallons of water from 80degrees F to boiling in 10 minutes. If when you place a cold barrel into your boiling tank and the boiling of the water dies away--you do not have enough heat--make a bigger burner.

I made my boiling tank of copper to eliminate all the rust by products of carbon steel tanks. Some barrel blackers do not like stainless steel tanks due the formula they use. See what works best for you.

Only preparing the surface only up to 320 grit emery cloth is an old wives tale. I go to 600 grit or more. If you are going to do best quality work the barrels must look best quality in preparation.

If you want to see the difference between a matte finish and gloss finish, examine them under a microscope. The matte finish will look like the surface of the moon where the rust formula has worked. Light cannot reflect from these pits you will see under a microscope, to provide a gloss finish. I keep a microscope in my shop(covered well) as it is very useful for a craftsman to have.

Do not mistake that you must see red/orange rust before the rusting cycle is complete. Yellowish or no rust color at all (only drab smokey color may be enough) may be all you need to reach to with your particular formula. Formula's seem to matter, but not that much in the overall scope of things. What matters most is what Damascus, SKB and PA24 have referenced.

I hope this is helpful for you lads.

Bv

Last edited by bushveld; 09/01/13 04:27 PM.