Powder Coating problems

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Daniel

Daniel

Member
Joined
Jan 1, 2004
Messages
5,921
Location
Reno, NV, USA.
I am trying to clear powder coat 50 cal casings. SO far I have tried two of them. Both have failed.
First I am not sure if I am getting the powder on thick enough to get an even smooth flow, but am not sure that is the problem.
It also looks like the powder may not be completely melting.
The first attempt was really bad. I did the second one and got better results but the neck of tha casing has what looks like very small bubbles or even grains of sand in it. I think this is actual granules of powder that did not melt.
I heated them to 375 degrees for 20 minutes after they started to flow like the directions say to do. But I suspect I need to go to a higher heat.
I also think I might have the casings setting to low near my metal plate and the powder is being drown to the plate and not the casing.

anyway any help in trouble shooting this would be appreciated. I am hopeing to be able to eventually do 8 to 12 casings at a time. but not sure if the system is strong enough.
 
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Are you using a oven? I'm not sure what you are referring to as metal plate.

I use a toaster over set at 400 deg after the finish looks smooth I go 20 min more.
I put my powder coat on until I can't see any brass. I always wipe all my brass down with alcohol then blow off with the air compressor before coating.
 
I wiped everything down and the powder looked to me like it coated well. Right now my best guess is I am not getting complete flow. I seem to remember someone once reporting they needed to go higher than the recommended 375 degrees also.

I am using a toaster oven. my rack is a metal tray that came with the oven. I drilled holes through it and stuck 3/8" bolts through them. I have noticed before that if the object you are coating is to close to this metal bottom tray the powder is attracted to it more than the object you are trying to coat. I'm not sure how I would make a wire rack to hold 50 cal casings, they are pretty heavy.
 
Wrap your bolts with aluminum foil so that it keeps your casing a couple of inch off the bottom of the pan that is what I do. I make a mound of foil so that very little is touching the shell casing.
 
Having powder coated items as small as a dime to motorcycle frames and skins, the one thing I have found that many underestimate is the continuity of the ground. Make sure the contact between the ground clamp and the rack and between the casing and the bolt is a good one. If not, it make look as though you've covered the casings well but when you remove your ground and move them to the oven, you can begin to lose some of the coverage.

I too use foil both at the neck and primer ends to increase the contact surfaces and also help in keeping the powder from getting inside these ends. I coat until they have a nice frosted look to them. Then I put them in the toaster oven which has already been preheated to 375 degrees. Once the powder melts, I usually let them bake for another 15 minutes.

Here is what I use for "normal" sized casings . . .

1_PCRAKX.jpg
 
I don't know where you get your powder but I LOVE this company's customer service AND it's powders. Here is the clear I use... http://tinyurl.com/9jfom7
It sounds like you're not getting the powder thick enough. The same thing happened to me, little sand like granules on the surface, and going thicker helped. You should just BARELY be able to see the color of the casings and the copper bullet. Also, a toaster oven has controls for top AND bottom heating elements, make sure it is on BAKE and that BOTH elements are coming on. Uniform heat is what you want. Also, PRE-HEAT the casings for a couple minutes, this will help the powder stick and make it easier to get full coverage. It also gets rid of any residual cleaner or junk on the surface.
 
Daniel - - I also had what appeared as a "grains of sand" effect on some of my earlier
castings. Finally discovered that although I was cleaning the exterior of the
cartridge with acetone - I was failing to clean the inside of the cartridge which
was somehow leaking dust/dirt onto the exterior casing.

Good luck - I've learned alot from your postings.

Gordon
 
Thanks everyone. I have a few ideas to try out from all of this. I will try another one or two but will have to give up on these if they do not start coming around. The two I have already messed up are the only real spares I have at this time.
 
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