Powder Coating Gun

[getastro]

Hello all, I just have a quick question; I have one of the higher priced hobbyist guns from Hotcoat ($699.99), but each time I try to second coat anything I get poor results. I have tried to replace the ground wire that I hang the part from after the oven, lowered the volts (the highest is 25k), but nothing. The only way I can second coat anything is to apply the first coat then to the oven or IR lamp for the proper time. After the parts is done remove and apply the second coat right away, the powder starts to melt to the part right away. I am looking to change this because I have few large parts that must be done soon and the oven I am putting together is not ready yet. I am also looking for an input on which industrial gun is the better one. Just looking for some help. Thank you all.

Getastro….

[non-stick]

I don't know how many hobbyists turned industrial are here along with me...so I'll just add my 2 cents in like usual and hope that helps you,lol.

For industrial use... I recommend the Gema/Ransburg guns with a fluid bed. Maybe a little tougher to use than the hobbyist models, but not impossible. As far as coverage with a second coat, I'll assume you missed spots and wish to go over it again? (very rarely do you need to build thickness with these powders for anythig that you guys are doing). RE-ESTABLISH your original grounding point! That is key. We work on the principal of electron flow with this type of coating (electrostatic resonance dishcharge) and if you can give then not receive the charge....it's all pointless anyways. The best way is to strip the part and re-do it all. Secondly, I'd scuff the heck out of it and smooth out all the rough patches to get a "like new" feel to it, and then finish off with a very fine grit paper. Wash down and clean clean clean your part. Now...recoat as per your original directions. Dependant upon thickness of coating, distance from gun to part (all you guys need to be stepping back a ways and let only the fine charged particles adhere....at least 18" away) and humidity conditions...your Kv should be at or near 20 range for a good solid coating. If that doesn't work....blow it off again and play with your voltage ( I have no clue the environment in your shop/garage...so this is why I said this). Re-bake like normal and Bob's your uncle so they say. I know I've said this all somewhere before it seems. Maybe it would be best for somebody to start a "tips and tricks" column where no questions can be asked and only what has worked for all of us can be posted,no? Just a thought.

Anyways....hope that helps for you. Good luck.

[getastro]

Hello non-stick, thanks for the info on the Gema gun that is the one I was looking at. I have a friend in the railing business and I could get a lot of work from him. As for the second coat deal, what I am trying to do is a silver metallic color base then a transparent blue top coat. The first coat is baked for half the time and the second coat applied with the air pressure turned down and the volts down too. Do not think the gun has the right amount of volts to charge up the part after the first coat. The powder only grabs in some spots, but not in others.

[non-stick]

ok.....two coat system. I got it now. I'd say basically you answered your own question there. You've basically insulated the part and now need to overcompensate for that fact by increased Kv. The Gema gun is the best I've used so far. I've never had one break on me or anybody that I know of (and trust me...that's a whole lot of people!). Easy to clean, care for and store. You could do worse than that gun if you need to go to 65Kv for a second coat in your process. Hope that helps......Russ

[getastro]

Thanks, non-stick
I call the Gema Rep on Monday.