First powder coating, results so/so, anybody use the cheapo HF unit ? Options

[jsteele22]

Last night I finally got around to using the "Chicago Electric" powdercoating setup I bought at HF a couple of months ago. It was on sale, like $60, and others have reported satisfactory results with it. I had some problems, though, and wondered if anyone has any ideas to help.

The problem was that the powder delivery was very erratic. Whenever I pulled the trigger or jiggled the gun the tiniest bit, a huge blast of powder would come out. Huge. I'd say, 1/16" or so of powder would splat out onto the work. After the huge splurt, the powder would come out in a reasonable manner, and go right where it was supposed to. Gradually, though, the fog would get thinner and thinner, and I'd have to shake the gun a tiny bit. This produced another huge splurt, then another interval of acceptable flow. To get by, I had a scrap metal shield that I kept in front of the work until the splurt was over, then moved out of the way during the intervals of acceptable operation. It works, but it's tedious and messy.


The instructions say to either use 10-15 psi regulated at the compressor, or to use the regulator screw on the gun itself. I'm using the shop at my work, and the compressor is off in a different room that I don't have a key for. So I bought a cheapo HF regulator that I screwed onto the gun, and before loading it with power, tried to test the operation. With the trigger pulled, I could - barely - regulate the pressure, but as soon as I released the trigger, the pressure would climb to line pressure. The POS Chinese regulator wasn't regulating. Then, based on the instructions, I removed the regulator and tried regulating the air with the screw built into the gun. No way of knowing the pressure, but from the sound I could hear the rate of flow and trim it to something reasonable. In any case, the air flow is smooth and steady.

Any tips or suggestions ? The obvious thing to try is buy a non-crap regualtor. But has anyone had luck using the metering screw in the gun itself ? My hunch right now is that maybe I had the air flow too slow. How rapidly should the powder coat the work ?

TIA, Jeff

p.s. I'm off skiing tomorrow; won't be back until Tues.

[seanery]

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[jsteele22]

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Pics of the finished job, or pics of the mess ?

The parts I coated were an oil pan and splash tray from a Subaru EG33 that I reworked (shortened) for putting in my 914 one of these days. The coating is black, so it's real hard to see anything at all in the pics. Here's one with contrast and gain cranked up fairly high. What can I say ? It's black. I missed a few spots on the inside, and they really stand out in the picture. I originally wasn't gonna coat the inside, and did it after the pan was hanging in its curing position, so some angles were tricky. For curing I used a catalytic propane heater and some sheets of scap metal set up behind the part as reflectors. (Sorry, no pics). The heat wasn't super-even, so I kept rotating and adjusting the parts/heater during curing. A proper oven would pobably be much more uniform.



Hey, that was picture # 666 for my camera. Coincidence ? I don't think so...

Here's a pic looking down into the pan, with the splash tray in place. Again, major contrast/gain tweaking. The splash tray was the first piece I coated. Towards the rear (top of pic) got less heat during curing, and came out more glossy than the rest. Also, I made several attempts on the tray (wiping it off w/ a paper towel), and it wasn't coated super -evenly, so you can see some bumps. I have no idea why the bottom of the pan (seen through pick-up tube opening) looks so white in the pic; in reality it is a nice, even black.