Powder coating effects on water dropped hardened boolits?

[mkj4him]

If I water drop my boolits to harden them a bit, and then powder coat using the 400 degree for 20 minutes method prior to sizing, will the water drop hardness be negated?

[GregLaROCHE]

Many believe so, that’s why they quench them in cold water immediately after baking.

[Dusty Bannister]

To take this one step further, I had the opportunity to use the Cabin Tree hardness tester on a couple of .460 caliber Flat nosed bullets. Cast from the same alloy and quenched. One was then powder coated, baked and quenched. I filed the base and the nose flat on both samples to remove any influence of the powder coating that might result in an influence on the reading.

The first quenched bullet was .092". The second bullet was quenched, powder coated, quenched and read .089". That is perhaps a difference of 1 BHN and could have been operator error, or just a slight unseen casting defect. But to me, it did suggest that the PC might have a slight insulating factor and reduce the speed of the quench.

In reality, the difference is so small that in this caliber, I would not be concerned about this slight variation. Smaller calibers might have a different result, and it would be good to have that information added to this thread. Dusty

[charlie b]

Yes, if you water drop to harden your bullets then the temperature and time of powder coating anneals the alloy some amount.

If you want the bullets to be harder, then water drop after PC.

And, yes, there is a chart for that around somewhere.

[MUSTANG]

I have found that water quenching PC'd boolits immediately after pulling from oven after 30 minutes baking gives about the same results as indicated in the table at the bottom of this article:

http://www.lasc.us/HeatTreat.htm

The table mentioned in the post above is at the bottom of the article.

[TjB101]

Air cool, PC, bake @ 400, water quench.

[Conditor22]

https://i.imgur.com/uclR2g1.png

[mkj4him]

Thank you for the information. It will be very useful

[Wolfdog91]

Here my findings

https://youtu.be/L9igUX85FMI

[GregLaROCHE]

Here my findings

https://youtu.be/L9igUX85FMI

I’d like to know where I can get one of those microscope holders for the hardness tester.

[44Blam]

Yep - air cool from mold, water drop from the oven and then wait a couple weeks if you want maximum hardness.