Does powder coating change the bhn?

T

totaldla

New member
I was wondering what the various baked on coatings do to bullet hardness.

Specifically the 400°f bake cycles, which seems very close to what you would do to air-cool or water quench for increasing hardness.
 
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R

reddog81

New member
PC is a very thin coating. It doesn’t change the underlying alloy. It does a great job of preventing leading. It’s not going to allow you to run soft lead bullets at rifle velocities.
 
D

dahermit

New member
Specifically the 400°f bake cycles, which seems very close to what you would do to air-cool or water quench for increasing hardness.
Click to expand...
If I am not mistaken, air cooling results in annealing (softening), bullets as it would with heat treating Carbon Steel. You have to quench to get the hardness.
 
M

Mike / Tx

New member
I have used an alloy that runs around a 10-12 BHN to pour solids and HP's for a couple of years. I've pushed them both coated and not up into the 1600fps range with a couple of my magnum revolvers and some solids up in the 2200fps range from my 308.

Groups have been very respectful and recovered bullets did not show anything that would lead me to think there was a lot if any difference between the two other than the coating still being intact.

As for the change in hardness, it may effect one blend of alloy more than another. The more antimony that is present the more it could change.
 
S

Seedy Character

New member
Wut Mehavey used


I have loaded MANY PC bullets in .30-30 and .30-06, up to 2500-2600 fps and NEVER had a problem.

Quenching will harden. BTW
 
U

Unclenick

Staff
Most of the coatings are set at about 400 degrees F. It's not quite warm enough for quench hardening most bullet alloys. But I don't see why quenching powdercoat would hurt it, though I haven't tried.
 
M

mehavey

New member
While cured (i.e., 400 degree/20min, etc), I find the coating is still sticky (soft?) until cooled.
Case in point: It will stick to parchment paper while still hot, slides right off when cool.

Would be interested in doing a smash test on quenched coating though...
(differential modulus contraction under shock?)
 
S

Seedy Character

New member
The bullets I powder coated, I quenched. Mot to "harden" per se, but to set the PC, so they didn't stick.

Smash test has shown the PC remains intact.
A comparison of BH on the bullet, before and after PC, would be interesting.
 
M

mehavey

New member
What I saw in that film was:

Air-cooled/Uncoated: 12.2
Air-cooled/Coated: 12.8 (insignificant)

The rest of it was (I think) the effect of partial annealing/second quench being at only 400 degrees
 
R

res45

New member
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