I'm certainly no professional rust bluer, just a serious hobbyist, but my method seems to work pretty well on the few guns I have done. There is a lot of BS and exaggeration circulating among hobbyists and gunsmiths. I tried to approach it from a scientific viewpoint. Because it is a simple process with simple components, there is not too much you can do to screw it up as long as you observe a few basic requirenents.

1. I never go beyond 320 grit (silicon carbide) used dry and as it wears, it will produce a higher gloss.

2. I have always used Laurel Mtn Forge Barrel Brown and Degreaser. The only gun of the 7 or 8 I have blued that it didn't work well on was the frame of a Nazi P-38. On the same gun, the barrel and slide were perfect. I use it because it was formulated by a pro and it contains a detergent which allows bare-handing the gun parts during coating, boiling and carding. No gloves, tongs or worries about skin oil contamination.

3. I use a damp box based on the one shown in Gunsmithing Tips and Projects ( Wolfe Publishing, out of print) because I have an air-conditioned shop and live in a dry climate as well. I usually run it about 80% humidity and 90°F. The solution is not too sensitive to the conditions as long as the humidity is at least 70%. Rusting time varies somewhat with the steel alloy. Mild steel like a shotgun barrel usually takes about 4 hours to look right while a 4140 rifle receiver might take 6 hrs. After a while you get a feel for the time needed.

4. I apply the solution sparingly with a dampened cloth pad. Too little is not a problem. Too much can cause pitting. 100% coverage is important.

5. I boil for about 10 min. I experimented early on with longer times up to 30 min. and could see no benefit.

6. I card with a 6" DIA. carding wheel running about 500 RPM where possible. Brownells sells some small brushes on wire shanks that can be run inside trigger guards and the like. 4/0 steel wool and SS tooth brushes(used gently) work in tight spots.

7. Number of coats varies with the steel alloy. Shotgun barrels usually start looking good after 4 coats. Modern rifle receivers and barrels might take 6. More rarely does any good and if you don't like the look, repolish and start over. The natural tendency is to run one more coat just to be sure.

8. I could never see any benefit to delaying the oiling after the last carding. Iron oxide is a stable compound and I don't believe in the "let it cure overnight" cautions I have read. I always use whatever gun oil I have handy which is usually Breakfree CLP. Oil is pretty much oil and I doubt it matters at all. I have heard of grease and even linseed oil being used. I suspect the main benefit is the temporary higher gloss they provide.



OB