My Old Tool Cleaning Process, as requested

[Stew Denton]

Hi Karl,

I don't know about the composition of gun barrel browning. I know from past study that conventional cold bluing is conversion of a very thin surface layer of steel to magnetite, Fe3O4, which then passivates the steel surface to an extent, and especially when kept oiled lightly will retard rusting.

I didn't know about the browning process, so looked a bit. I could not find anything on browning from chemistry, so looked in general. The gun browning articles that I found describe the browning as a fine layer of Fe2O3. The browning is done in such a way that it is a very thin passivating layer that adheres tightly to the steel surface, as I think you were thinking. This thin layer of Fe2O3 then also passivates the steel surface, and also again, especially with a thin layer of oil, helps also to protect the steel surface from true rusting to a strong extent.

If the information is correct, it would appear that the browning process prevents formation of the iron hydroxides, carbonates, hydrates, that are hydroscopic and are the bad actors in rust that helps encourage further true rusting. The browning process is acid based, so the process would likely prevent some of the above materials, because the acid would react with the precursors and neutralize or eliminate them. Apparently the pure Fe2O3 layer again passivates the surface, again especially with oil, in somewhat the same way that bluing does. The key, from my thinking then, is again a PURE layer of Fe2O3 that has none of the other bad actors.

Sorry I couldn't give a better answer, and in fact I would like to better understand the process myself.

That said, I have an old Stanley Bailey #5 type 12 plane that has a beautiful patina on the body and lever cap, that has not even the slightest hint of rust. The body and lever cap are a beautiful glossy brown. I am really tempted to leave the body and lever cap of that plane completely alone, and just clean them thoroughly with a soft cloth and mineral spirits, and then wax them. I would still refinish the tote and knob, and clean up the iron, chip breaker, etc. The bed of the plane has some significant rust spots, and I might clean those spots up, strip off the old Japanning, and redo the Japanning on the bed and frog. If I did that, cleaned the plane thoroughly, cleaned and polished the brass parts, and cleaned up and polished the other metal parts, the plane might look spectacular with the body having a nice glossy medium brown patina. I've got to think it over, but right now that is what I am strongly leaning toward.

Stew