I've been playing around with it on a small scale with one of the Neycraft electric furnaces from Brownells. Basically the procedure that I use is as follows:
Start with a highly polished item of steel, I typically finish it to 600 grit by hand and make sure the sanding scratches are running in the same direction. Haven't tried buffing, since I don't like the things.
The part can be degreased, though I can't say I have been able to tell much difference between the parts that were and the ones that weren't. I bury them in finely ground, hardwood charcoal in a steel pipe where I have one end welded shut, the other end sits on a steel plate carrier and I place extra charcoal around the edge to help seal it. I have tried homemade hardwood charcoal, and I have tried the stuff you buy from Brownells for color case hardening, long story short, use the Brownells charcoal and you can expect consistant results, use the other stuff and your mileage may vary. This is actually the same situation I have encountered when color case hardening, but that is another story. I make sure that the part is centered in the crucibal and not touching the sides. The whole works goes into the furnace at about 900 degrees for half an hour, I than shut the furnace down, let the part cool slowly to 150 to 200 degrees and take it out, and than place it back into the charcoal again, and fire the furnace back up to 900 degrees and let it sit for another half hour, follow this by a cool down cycle, take it out when warm, and than coat it in heavy oil (I use motor oil) and let it sit overnight. The reason for the cool down and reheat cycle is to move the part in the pack to ensure an even exposure. This helps to even out the color. Some people look for a splotchy color of varying hues of blue, I personally think this looks like manure, I want the part to be a deep, rich, wet ink type blue. Unfortunately, it ends up looking very close to a modern hot dip blue when done as I've described, the unknowledgable folks would think that is what you have. It takes a trained eye to detect the subtle difference of the two processes. That is all I can say, obviouslly to do a 42" barrel you would need to adapt the procedure, I wouldn't want to try it in a fire pit, If I was going to do it on anything larger than a pistol or pistol barrel, I would build a large electric furnace capable of holding a 50" cruicibal in. Hope this helps.
Alex Johnson
