BHuij
Active Member
Hey everyone--
I'm trying to push the envelope on what's possible with heat treated, plain old clip-on wheel weight alloy, since I get it for free. I wanted to really carefully document my experiments so I could share them with the community and give back a bit. I just finished my first set of experiments, and learned a lot. I sat down to write up my results, and when I was done I had roughly 17 pages, which will definitely not fit into a forum post. So I have linked a PDF for anyone interested. Basically I was heat treating bullets at various temperatures and then tracking their BHN over time. The kicker is that all of this heat treating was done after powder coating, so I could find out if PCing interfered with the heat treat, or if the heat treat destroyed the powder coating. See page 12 for the actual data.
Full write-up: https://drive.google.com/file/d/1zzZaz1oWxb6VsOB4RrVN-YFijxWAZ9ff/view?usp=sharing
TL;DR Version for those who have lives and don't want to read the whole thing:
Anyway, thought I'd share. More to come as I continue to tinker. Posted this on the other forum as well (and Reddit).
I'm trying to push the envelope on what's possible with heat treated, plain old clip-on wheel weight alloy, since I get it for free. I wanted to really carefully document my experiments so I could share them with the community and give back a bit. I just finished my first set of experiments, and learned a lot. I sat down to write up my results, and when I was done I had roughly 17 pages, which will definitely not fit into a forum post. So I have linked a PDF for anyone interested. Basically I was heat treating bullets at various temperatures and then tracking their BHN over time. The kicker is that all of this heat treating was done after powder coating, so I could find out if PCing interfered with the heat treat, or if the heat treat destroyed the powder coating. See page 12 for the actual data.
Full write-up: https://drive.google.com/file/d/1zzZaz1oWxb6VsOB4RrVN-YFijxWAZ9ff/view?usp=sharing
TL;DR Version for those who have lives and don't want to read the whole thing:
- You can powder coat, let the coat cool and cure, and then heat-treat up to at least 425 degrees for 90 minutes (where I maxed out) without ruining the coat (at least using Smoke's Clear PC). This gives you the advantages of a heat-treat/quench AND powder coat simultaneously.
- My pure COWW alloy, at least, was able to get up into the high 20s for BHN using this method with 9mm projectiles. With .223 projectiles I was able to get up to nearly BHN 35. All of this is after powder coating.
- My COWW alloy appears to get pretty close to stable hardness by the end of 7 days, but just to be safe, I'm going to continue giving bullets a full 14 days before shooting them. Your COWW may reach stable hardness sooner or later than mine based primarily on arsenic content. But I think I've confirmed, at least to my own satisfaction, that 14 days is a good universally safe amount of time to wait before loading/firing.
- I have come up with a few more questions I want to answer through experimentation about heat treating and quenching--such as "does it matter how cold the bullets get when quenched, or just how fast the bullet temperature drops below a certain threshold?" It seems like one or both of those things changes your BHN after heat treating, since my smaller bullets got to higher BHNs with the same heat treatment as larger bullets.
- The Lee hardness tester introduces some inherent human measurement error, particularly in the higher end of the BHN range it is capable of measuring. For future experiments, I'm going to be averaging at least 5 bullets for each "reading" to counteract that, as well as tracking standard deviation to help me know how confident I can be in my data. But 1 bullet per test just isn't enough for really useful results.
Anyway, thought I'd share. More to come as I continue to tinker. Posted this on the other forum as well (and Reddit).