PSA on preheating for powder coating.

[gds]

I had some Lee 160gr .30 cal tumble lube boolits. that I had already tumble coated. I actually had forgot about them, and found them the other day. Decided to powder coat them. put them in a bucket with some mineral spirits over night then put them in another bucket with some paint thinner. Been busy for a couple of days. Had some time to powder coat them tonight after work. Pulled some out of the bucket and set them in my tray of 9mm cases. let them sit for about 20 minutes on top of my oven. while doing some other things. Placed them in the oven to pre heat. While I was running some that I had already powder coated thru my lee sizer I heard a poping sound. I turned around and another tray that was cooling had a round laying down so I thought maybe it had just tipped over. So i turned around and kept sizing and I heard another pop. I turned back around and heard another a couple more pops and i realized that the popping was coming from inside the toaster oven. I opened up my toaster oven and another pop and a gas check landed on the toaster oven door. :o

91791

91792

yes they all started off with gas checks on them.

Moral of the story, i have no idea. lol. I think maybe there was some thinner that had seeped under the gas check while it set in the bucket. but who knows

[RP]

I think your right the thinner trapped under the checks it may have dried out over time. Now we know not to soak and cook thanks for sharing.

[bangerjim]

Your checks were not on reeeeeeeel good & tight. Even if tight, thinner will get in there and hang around for a long time.

The thinner got under there and the heat rapidly expanded/vaporized it, causing them to pop off.

If you soak grease-coated GC's boolits B4 PC'ing, let them preheat to about 150F for a while and then let set for at least a day. Preheat time is a SWAG, so use your own judgment, just do NOT go into a hot oven immediately.

Thanks for pointing that out! One of those things we really do not even thing about.....until it happens.

banger

[gds]

Pretty much what i was thinking. I mean there was no velocity to them, but the few moments it took me to figure out what in the world the popping sound was, kind of made it funny.