Inspired by PhysDoc's experiments in charcoal bluing, I thought I would try mimicking it in a lead pot. This thread makes the process sound like it is totally temperature driven and not a chemical process like rust bluing. That begs the question, exactly what IS the chemical nature of charcoal blue, but I skipped past that to try the lead pot.
In my 20# Waage pot, I normally cast at 800 F (measured with a Lyman casting thermometer). Its thermostat is nearly maxed out at that temp, but I was worried about getting into forbidden territory above 900F so, I figured it might suffice. I set up in the driveway to be a little safer with fumes.
The pot got to just under 900F. About 880F or a titch higher. That's as high as I was willing to go.
I had two pieces of dovetail filler bar that I had polished quickly to 1000 grit. I cleaned those in Acetone and deliberately placed a finger print on each of them.
I wired the pieces to some soft iron wire and sunk them in the pot. This could have been thought out a bit better, but it worked.
After 10 minutes, I pulled one piece. As it came up through the surface, it collected some dross that did not shake off or knock off as I anticipated (as lead will flake off a mould's sprue plate). I fetched a wire brush, but it would not rub off very well either by that point. I plunged it back in the pot with the first piece still in there. At the 20 minute mark, I pulled both, but this time I carefully cleared the surface of the lead first and I immediately rubbed the parts down with the brush. This worked much better, but far from good. I would not want a whole action to deal with like this.
Overall, the color was not a deep black but rather a shallow very dark grey/blue. Somewhat mottled and definitely think. It was close, and it was rather attractive, but it was not what I had hoped for. The 1000 grit shine held up pretty well however. There was no trace of either finger print. Both parts were about the same, as the first one was when pulled the at the 10 minute mark. Therefore, I don't think more time is the solution.
In conclusion, I think 880F is not hot enough. Hotter is not a viable solution using lead. The dross problem is another issue.
Perhaps nitre salts would get hot enough and work perfectly, but I suspect there is more to this than heat and that's why they used charcoal in the old days.
Anyway, I hope someone else decides to experiment and finds better results. I'm looking at my grills and wondering how I could make this work.
![[Linked Image from i.imgur.com]](https://i.imgur.com/qclHjMQ.jpg)
