BHN after powder coating

[MR CHEN]

Will the powder coating process (400*for 20 min) soften the bullet alloy.
If so, is there a rule of thumb, or do you have to test?
My alloy is 9.5lbs coww and 0.5 lb of 60/40 soldier. According to bumpo628s calculator it should be a bhn of 12.2. Don't want to go any softer or harder.

[mehavey]

If you're normally air-cooling (vice water drop), no appreciable effect.

FWIW: I wouldn't rely any any alloy "calculator"
Get a Lyman BHN tester and get a measured number.

[la5676]

I'll post a really silly kweshun here, as I'm new to PC. I've never shot anything but straight COWW on pistols with the old traditional lube, always some mix of lino and COWW for rifles. I'm going the PC route now for all my pistol shooting. Question is, if the PC is providing a "jacket" more or less, is the BHN really that much of an issue anymore. The lead never comes into contact with the rifling (if your PC coating is good). Obturation is obtained easier with softer lead not driving so hard. Is there another factor at play here with the PC method different from the old 45-45-10 lube method? Curious minds need to know.

[JonB_in_Glencoe]

Will the powder coating process (400*for 20 min) soften the bullet alloy.
If so, is there a rule of thumb, or do you have to test?
My alloy is 9.5lbs coww and 0.5 lb of 60/40 soldier. According to bumpo628s calculator it should be a bhn of 12.2. Don't want to go any softer or harder.

PC process (bake@400º) will anneal or partially anneal your alloy.

[JonB_in_Glencoe]

I'll post a really silly kweshun here, as I'm new to PC. I've never shot anything but straight COWW on pistols with the old traditional lube, always some mix of lino and COWW for rifles. I'm going the PC route now for all my pistol shooting. Question is, if the PC is providing a "jacket" more or less, is the BHN really that much of an issue anymore. The lead never comes into contact with the rifling (if your PC coating is good). Obturation is obtained easier with softer lead not driving so hard. Is there another factor at play here with the PC method different from the old 45-45-10 lube method? Curious minds need to know.

PC is not a jacket, it is a lube.
Everything that applies to a Rifle load and Bhn, still applies.

[cwlongshot]

PC is not a jacket, it is a lube.
Everything that applies to a Rifle load and Bhn, still applies..

I beg to differ. A powder coat properly applied is a “jacket” by all definitions I’m aware.

I have done my own tests and continue to see reduction to hardness from powder coated bullets that are not quenched in water out of the oven.

CW

[fcvan]

The PC ‘jacket’ does not act the same as copper as it is very thin and takes less to disrupt the coating. However, that thin layer is very tough, very slick, and does operate like a jacket. Certain semiautomatic cartridges suffer damage during cycling but not so when coated with PC.

I have a 9 mm AR15 that hates anything not round nosed, including RF and TC. It feeds RN all day long without deformation, whereas even plain lubed RN even shows mild deformation. Where I am really seeing some promise is with 223 Rem using a PB boolits. I still need to sweeten the alloy a tad in hopes of tightening groups, but my usual pistol lead is doing well at 2250-2450 FPS depending on barrel length. More testing is needed there, but 223, 308, and 30-06 are fantastic with same alloy, 2250 FPS, and gas check. The PC coating leaves nothing behind but gunpowder residue.

[cwlongshot]

256611

Properly applied PC stays on!

CW

[Conditor22]

PC is an elastomeric polymer coating (polyester) that functions as a lube

https://i.imgur.com/CmmjY2S.png

[Silvercreek Farmer]

PC is an elastomeric polymer coating (polyester) that functions as a lube

https://i.imgur.com/CmmjY2S.png

Nice chart! Any chance you have or could do COWW mixed with pure? Say maybe 50/50?

[la5676]

I do enjoy reading and picking up any and all info on this site, but at times I have to shake my head and say what the heck. In the chart above, I see it helps boolit hardness to water quench after PC. In my many hours of bingeing on youtube PC videos, I watched more than a few recommending water or ice water quenching right out of the oven. Not a few days ago, I just read on this forum (and I couldn't locate the thread now if my life depended on it) that one needs to let the PC cool down slowly to cure properly, or I assume it will get brittle. Just when a guy thinks he has a handle on things, he reads some more and gets confuseder. :roll:

[MR CHEN]

If you're normally air-cooling (vice water drop), no appreciable effect.

FWIW: I wouldn't rely any any alloy "calculator"
Get a Lyman BHN tester and get a measured number.

I'm going to get a tester.

[MR CHEN]

It looks like I have 4 that say no (will not soften) 1 yes, and five off topic.

[la5676]

It looks like I have 4 that say no (will not soften) 1 yes, and five off topic.

I'd really like to find the comments I referenced above and put them here too. But, I think you made the right choice, get your own tool.

[Conditor22]

It looks like I have 4 that say no (will not soften) 1 yes, and five off-topic.

:groner::killingpc[smilie=b::killingpc[smilie=b: unfortunately this is getting to be the norm

[bmortell]

im sure going from air cooled to pc cooked and air-cooled is technically different but less than anything your gonna notice or even measure maybe

[Gohon]

PC process (bake@400º) will anneal or partially anneal your alloy.

Only if the casts were water dropped after casting. The BHN of a alloy cannot go below it's original state. So if your casts were air cooled and came out at 12.2 then 12.2 is as low as the BHN will go after baking powder coating.

[barnabus]

:groner::killingpc[smilie=b::killingpc[smilie=b: unfortunately this is getting to be the norm

that's why I dismiss over half of what the experts say on here

[la5676]

that's why I dismiss over half of what the experts say on here

Bizzactly.

[Dimner]

PC is an elastomeric polymer coating (polyester) that functions as a lube

https://i.imgur.com/CmmjY2S.png

I might not be adding to the conversation. But a HUGE thank you for this chart. :)

[MR CHEN]

I was able to get a Lee Hardness Tester, and after checking - air cooled @ 13.4 and air cooled PC @ 13.9 it looks like there is no softening to be concerned about.
I'm going to test the air cooled/water dropped pc next.
Thanks everyone.

[TRM]

I was able to get a Lee Hardness Tester, and after checking - air cooled @ 13.4 and air cooled PC @ 13.9 it looks like there is no softening to be concerned about.
I'm going to test the air cooled/water dropped pc next.
Thanks everyone. thank you another myth busting.

[fredj338]

It looks like I have 4 that say no (will not soften) 1 yes, and five off topic.

IT does soften the alloy a bit, if you water dropped out of the mold. Easy enough for anyone to test.

[mehavey]

If cast air-cooled to start/before PC'g
it will be exactly the same after air-cooled PC'g

(Make that Five saying No Difference)

[la5676]

Can anyone 'splain to me the difference in the chart on page one of water cooled (showing a BHN of 27) and a quenched cast/quenched PC (showing only 24 BHN). Is this showing the loss in quenching from only 400 degrees on the PC step, whereas the original quenching (water cooling) would have been from 700 degrees +/-.

[bmortell]

ya heat treating from a higher temp makes harder boolits. then reheating in the oven resets it to be heat treated at a lower temp this time in the water. but from the mold is probably like 475 ish by the time it hits the water, at 700 youd be pouring liquid from the mold

[la5676]

ya heat treating from a higher temp makes harder boolits. then reheating in the oven resets it to be heat treated at a lower temp this time in the water. but from the mold is probably like 475 ish by the time it hits the water, at 700 youd be pouring liquid from the mold
Uhhhhhhh, there's that. But, ya know what I meant.

[MR CHEN]

As I stated in post #21, "I'm going to test the air cooled/water dropped pc next".
It didn't go so well. I dropped right out of the oven, waited a day then measured for hardness and saw no increase in BHN.
Right out of the oven I tell ya! What could be wrong?

[tazman]

I would have expected the antimony in the wheelweights to cause at least SOME hardening when quenched. When I water drop wheelweight lead, it gets much harder than air cooled. How much, I can't say. I don't have a tester.
I can scratch the air cooled boolits with my fingernail but not the quenched ones.
I have to wonder if you are testing the hardness of the PC coating as opposed to the lead?
I am not familiar with the process of lead hardness testing so perhaps my question is a bit on the ignorant side.

[bmortell]

it deffinitly works I do it with almost everything I shoot, towards the end of cooking I get it up to 425 for a few minutes, then fast as I can take the tray out and throw it in bucket with some ice water. then let em sit for a week to get hard. I expansion tested after 1 day before and it showed there harder than air cooled but not as hard as aged it takes time. I use half ww half pure and they get pretty hard, pure even harder

you can always put em back in the oven if you need to, nothing is lost either way

[Gohon]

pure even harder

I've never heard of pure lead getting hard after water dropping unless antimony is added.

[bmortell]

ah, pure as in pure wheel weights instead of half and half lol

[MR CHEN]

I would have expected the antimony in the wheelweights to cause at least SOME hardening when quenched. When I water drop wheelweight lead, it gets much harder than air cooled. How much, I can't say. I don't have a tester.
I can scratch the air cooled boolits with my fingernail but not the quenched ones.
I have to wonder if you are testing the hardness of the PC coating as opposed to the lead?
I am not familiar with the process of lead hardness testing so perhaps my question is a bit on the ignorant side.

I'm using a Lee tester and removed the powder before testing. With the Lee you file a flat spot on the bullet to test.

[MR CHEN]

it deffinitly works I do it with almost everything I shoot, towards the end of cooking I get it up to 425 for a few minutes, then fast as I can take the tray out and throw it in bucket with some ice water. then let em sit for a week to get hard. I expansion tested after 1 day before and it showed there harder than air cooled but not as hard as aged it takes time. I use half ww half pure and they get pretty hard, pure even harder

you can always put em back in the oven if you need to, nothing is lost either way

I did not use ice water, garage temp. Not real cold but cool.