Dang powder coating!

[barnabus]

I have had great success with 9mm powder coating and sizing. Today I poured 1000 357 Mag 150 grain bullets and coated them with Smokes Jet Black. I went to size them at .358 when I went to size it took all the powder coating off. I shake off all excess powder coat and once baked they are .362 I'm using a RCBS sizer and it appears the coating is just to thick. Any insight that could help me?

[TexasGrunt]

What size are the boolit before you coat them?

[Smk SHoe]

I had same problem with .358 bullets I cast and coated and sized same day. Just a hot mess. Then I decided to cast one day and powder coat and size another day. Worked for me. Seems I was trying to rush to get everything done and didn't give each step it's proper timing.

[runfiverun]

try a LEE push through size die the taper and press advantage will help too.
I also wait after making them and then again after cooking them.
it's like dry paint.
there is dry enough to put a second coat on, and there is cured and settled paint.
I know PC should be done when cooled but [shrug]

[flyingmonkey35]

I have never had this issue but i have had to size. Pc then size again. As im going down a lot. .360 to .356.

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[barnabus]

Is this a problem related to the 357 mag? It makes a mess of the bullet. I tried some i did last week just to make sure they were cured and they did the same thing?

[Bzcraig]

Is this a problem related to the 357 mag? It makes a mess of the bullet. I tried some i did last week just to make sure they were cured and they did the same thing?

No, the powder has no idea what caliber you're coating. Sounds like you're coating fat boolits then trying to size down too much.

[flyingmonkey35]

Show us a photo before and after.

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[Grmps]

Is this a problem related to the 357 mag? It makes a mess of the bullet. I tried some i did last week just to make sure they were cured and they did the same thing?

Coating failure is often caused by bad thermostats on counter-top ovens. Best solution is a PID on a convection oven, a simpler solution is thermometers set in the middle of the shelf you bake on, adjusting the oven temp setting until the thermometers reach 400 degrees. If the coated object doesn't reach and maintain the given temperature for the prescribed amount of time, IT WILL FAIL

[barnabus]

Coating failure is often caused by bad thermostats on counter-top ovens. Best solution is a PID on a convection oven, a simpler solution is thermometers set in the middle of the shelf you bake on, adjusting the oven temp setting until the thermometers reach 400 degrees. If the coated object doesn't reach and maintain the given temperature for the prescribed amount of time, IT WILL FAIL

this is not a cooking fail as ive checked my oven temp with two different temp gauges.seems others are experiencing some failure with 357 mag too. it seems the jet black is adding about .003 or .004ths coating even after knocking off excess powder.i wonder is smokes clear is thinner.

[randyrat]

Try my coating, I think it goes on thinner.
http://castboolits.gunloads.com/show...ating-for-sale

[rototerrier]

If you can hammer the bullet into a cube and as flat as a penny, then you probably have it cured properly. If you've over cured / over heated, then you'll get flaking when you hammer test. Not sure you can under cure. I've never done it...so going to assume that's not your issue.

I'd suggest getting a LEE push through sizer for this task. After switching to PC, my lube sizer never comes off the shelf. It's not really the best tool for the job and is much slower.

Sounds to me like your RCBS is too tight and is shaving the coating off. I currently use both LEE and the NOE sizer/bushing setup and neither have given me any trouble and I've sized some down a lot. I just sized some .458 down to .452 without issue. With PC, you are going to get bigger bullets, so this issue isn't going to go away unless you custom order your molds from NOE / Accurate/ etc to be slightly smaller to account for the added PC thickness. I'd go with a cheap Lee sizer before going for a new custom mold.

[BNE]

What size are the Bullets before you coat? Try pushing one through the sizer before you coat. I suspect your casting much larger than you realize. I had the same issue before and just holding the mold handles tighter fixed it for me.

[Morgan61]

That's why I size my cast bullets twice. For my 30cal bullets I size to .310" prior to powder coating then I size them at .311" after powder coating

[barnabus]

What size are the Bullets before you coat? Try pushing one through the sizer before you coat. I suspect your casting much larger than you realize. I had the same issue before and just holding the mold handles tighter fixed it for me.

This is a possibility

[fredj338]

I size all my coated bullets after, no issues with it comeing off in the sizer, most of the time. If there are any small fins on the base, that can be an issue. I use pass thru Lee dies.

[runfiverun]

if your getting .004 or even .003 you got too much powder on them.
.002 would be more correct.
Randy's dark grey cooks into about .001 thick [.002 total] just with a whiff of it in place.
if you clump the powder on it runs to the bottom and flashes.

[Walter Laich]

Got a new Lyman mold .454 that I needed to size down to .452.

case, PC then sized...not a problem at all. Using Smoke's powder

[Grmps]

+1 on the hammer test. if you can flatten (both ways) the baked and well cooled bullet without flaking you baked them properly. You need to remove all excess powder before baking. I've cast / coated and sized 1000's of .358-158 RF in the last couple months with no problems.
the powder coated bullet needs to reach and hold a certain for a few minutes to cure, most people seem to bake for to long. 10 min in a preheated oven @ 400 degrees has worked well for me. Some powders require longer & slower baking. I sized down 4 thou without issues. You could check your sizer for sharp edges.

[Advil]

Randyrat is also correct. We've used several different types of powder. Some go on really too thick even when you try to shake off the excess. Had to give up on a color we liked because it was producing bullets too big to size. As everyone else had said though the coating should stay on just fine when sized. Cook at a higher temp, and possibly longer. We could not get good temp control out of our existing toaster. Got one with a digital control. Works perfect.