Help with small raised specks

[teslamaster]

My problem is that I get small raised specks on *everything* I coat. They are each about the size of a grain of sand. There is about one every square inch on average.

I have the Eastwood hobby gun.


Any help would be great. Here are the thinks I have thought of and tried:

-I am blasting parts with glass bead and thought maybe it could be the beads that didn’t all come off. I tried going over parts with a green scouring pad to get any glass beads off which didn’t work. I have since coated a piece of aluminum foil (not blasted), and still had the problem.

-I though it might be outgassing, but heating it to 50deg over the curing temp for 45min didn’t help, and I still have the problem with non-cast parts. I have coated 6061 aluminum, stainless steel, cast iron, aluminum foil, steel, and various other things. They all have the same problem.

-I thought it might be moisture from the air supply. I still have the same problem with a water/oil separator and desiccant dryer at the air supply and a disposable moisture separator (at the gun).

-I thought it might be sawdust from the shop. I tried setting up a tent (very clean inside) and shot inside of it. I also misted water on the floors and walls to keep dust from getting into the air.


I am completely stumped. Any help would be absolutely great. Unfortunately I need to coat a set of rims in the next week (I might be able to wait just a little longer), and if I can’t figure it out I’ll just have to live with the specks. This is driving me crazy…

[Brintiff]

have you tried different powder? Maybe the powder is contaminated.

[welterracer]

Ive heard that glass bead can cause these types of problems..

It could also be dust..

Make sure you spray from 8-10 inches away from the part.. Its easy to want to spray right up close, and end up with over build!

If you had oil or water in the powder there would be craters or bubbles in the powder..

[CarWiz]

Did you bake it in the tent too? Where's the oven? How did you get from the tent to the oven? Do you have a circulating fan in the oven? Is the oven clean?

It's obvious the problem is contamination. If you have sawdust in the shop, it sounds like it's getting into your powder or oven. Dedicating a closed area for your PC operations may be the only cure for your problem.

[teslamaster]

Thanks guys.

I have tried different powders, so it probably isn't that.

I get it on unblasted parts as well so I ruled out the glass bead.

The oven is pretty clean (I cleaned it pretty well before using it each time), and has no circulating fan. I think you are right though, I has got to be dust. Unfortunately I can't close off a section of the shop since it isn't mine. I think I am going to try building a tabletop spray booth and see if it helps any. I'm still worried about moving it to the oven after spraying though...

[aepowdercoating]

Thanks guys.

I have tried different powders, so it probably isn't that.

I get it on unblasted parts as well so I ruled out the glass bead.

The oven is pretty clean (I cleaned it pretty well before using it each time), and has no circulating fan. I think you are right though, I has got to be dust. Unfortunately I can't close off a section of the shop since it isn't mine. I think I am going to try building a tabletop spray booth and see if it helps any. I'm still worried about moving it to the oven after spraying though...

how big is you oven?? you can build what i did when i frist started i put the booth on top of the oven. i moved all the dials to the front of the oven, and made a top for the booth to sit on.next i put the oven on rollers so it could be moved a round as well. so when you move parts all you have to do is spray them and put them right in the oven.

hope that helps some..

[teslamaster]

It's just a normal household oven with all of the unnecessary parts stripped off. Actually, the dials are already relocated. Right now the oven is underneath a cabinet. If I can move it somewhere else I may do that. If not, I might put wheels on it and just move it RIGHT next to the booth whenever I am using it.