First let me say that there are other ways to accomplish this task and get fine results but I find this works for me with what I have available to me. The items below are the materials that I use for rust bluing a barrel.
Mark Lee #1 Express Blue, small glass container, tap water (I have a water softening system in the house), Coarse cloth such as heavy denim, Terry cloth towel, or maybe burlap which I have not tried, rubber gloves or the like, heat source to heat up gutter, water for boiling, something to plug the openings in the barrel so no water can enter, and a degreaser.
DHC Silky Cotton Pads (or any soft cotton type applicator pads)
I use a length of steel gutter from Home Depot that I solder on end caps to contain water. I suggest to make the gutter length 2 to 4 inches longer than your barrel plus tang and muzzle plug.
Bend up some stiff wire (qty-2) to support the barrel at each ends in the gutter so that it does not contact the bottom. NOTE: if rust bluing a lock or small parts I use a small disposable aluminum “loaf pan” and just put the parts into the water without trying to support the parts off the bottom – the bluing comes out fine - might also work for a barrel but I have not tried it.
OK – now for the barrel preps. What I will be discussing here is what I did for this barrel and for the finish results I was looking for which was a dark blue/black non-polished look which is what I do the most of.
This is what the barrel looked like before and after the rust bluing process described here. These two barrels are the same, made by Ed Rayl as received from Dixon’s Muzzle Loading Shop.
I did not draw file the barrel. I did block sand with both 220 & 320 grit wet/dry paper quickly. I did not try to remove all surface marks just to “knock down” heavy machine marks. I then used a medium wire wheel to even the surface out as best as I could – the corners of the flats did get “eased” some – don’t go hard with the wire wheel unless you want a “distressed” look. At this point you want to degrease the barrel good - I used acetone. I made up a barrel holder from scrap wood so that I could apply the Mark Lee #1 Express Blue.
I plugged the touch hole, my breach plug was already installed. I slipped the barrel into the barrel support and put on my “rubber”(Nitrile) gloves. I degreased the barrel again. I poured a small amount of the bluing into a small glass container and dipped my cotton pad into it – squeezed out most of the excess and starting from one end of the barrel and made a continuous pass towards the other end of the barrel. I did the same with the other 7 flats. NOTE: reapply the bluing solution to the pad to keep it wet but not “dripping” wet. When completed set aside for 4 hours. NOTE: I did not have a “sweat box” I just left it as you see it in the picture above – temp in CA was 104 degrees outside at the time. After 4 hours I reapplied the bluing solution as above and set it aside for another 4 hours. I did this process two more times and left it overnight (13 hours).
I placed the gutter over the two gas burners of MY kitchen stove and filled it with MY tap water to 1” – 1-1/2” above the top of the barrel (try to keep this water level throughout the process). I placed the stiff wire supports for the barrel that I previously bent to shape into both ends of the gutter. Turn on the gas to high. While the water is heating up I put on my “rubber” (Nitrile) gloves and plugged the muzzle of the barrel. I reapplied the bluing solution but this time I wetted the pad with more of the bluing solution then I did in the above step and set it aside until the water was as hot as I could get it (just about to bubble). I then placed the barrel into the water and leave it there for 10 to 15 minutes.
Removed the barrel (be sure you have your “rubber” gloves on – also the barrel WILL be HOT), dry it quickly and reapplied the bluing solution with a new pad. NOTE: keep the pad very wet this time with the bluing solution but do not “puddle” the solution on the barrel. Let the bluing work for 5 minutes then place the barrel into the hot water for another 10 to 15 minutes. Remove the barrel after the allotted time and take your course cloth and buff the heck out of the barrel (1 or 2 minutes). Reapplied the bluing solution with a new pad. NOTE: keep the pad very wet with the bluing solution but do not “puddle” the solution on the barrel. Let the bluing work for 5 minutes then place the barrel into the hot water for another 10 to 15 minutes. Remove the barrel after the allotted time and take your course cloth and buff the heck out of the barrel (1 or 2 minutes). Reapplied the bluing solution with a new pad. NOTE: keep the pad very wet with the bluing solution but do not “puddle” the solution on the barrel. Let the bluing work for 5 minutes then place the barrel into the hot water for another 10 to15 minutes. Remove the barrel after the allotted time and buff the heck out of it for 1 to 2 minutes then check if it is the color you are happy with - if not repeat the above process. If the barrel IS the color you are happy with you can now do two things to the warm barrel; First – remove all plugs then either apply oil or a wax LIBERALY – TWICE – let stand for ½ hour then wipe off excess oil or buff the wax. Set aside for at least 12 hours keeping an eye on it for signs of rust – if you see rust then buff out with cloth and reapply oil or wax. NOTE: I use a half & half wax mixture consisting of melted carnauba flakes and a high quality paste wax. That’s it – hope it works out like you want – does for me.