powder coating issue

[8EL]

Having an issue powder coating my stock 1931 rims. Rims have been sandblasted to a white preparation, and sprayed down with acetone to remove any possible oils or contaminants. Using an Eastwood dual voltage gun on low voltage setting (15 Kv) and not getting a transfer of powder around spokes. Part is grounded directly. pointing directly at spoke area and powder not being drawn to part. Suspect "Faraday Effect" issue, has anyone successfully powder coated their rims with this setup?

 

[BRENT in 10-uh-C]

We started out with their gun probably 20+ years ago and then graduated to a better gun. Haven't powderpainted in probably 10 years because I didn't find it was any better than spraying a solvent-based paint.

With that said, it sounds like you need to fluidize your powder first. Also, let the metal tip spark against the metal a few times to ensure you have a good connection. Make the spark jump the gap and pull it away gradually to see what kind of spark you can get to jump. Check to make sure you are not using too much air pressure. Also, you might take the diffusor tip off of the rod and make sure the rod is clean.

 

[8EL]

According to the OM the powder is fluidized in the cup on the Eastwood dual voltage gun system. I did hold the emitter next to the part an energized the power supply on both voltage ranges and did note an arc that would jump a half inch air gap. The OM does caution here that this test should be seldom performed as repeating will result in permanent power supply damage will be the result. 8 PSIG was supplied to the gun air side.

What I have learned from this is that the Faraday cage phenomenon is a major consideration with this process. Entry level guns like the one I bought will work fine on flat parts mostly. Any tight corner or region like spokes on this particular target do most definitely set up repelling fields to the powder being applied. The solution appears to be the ability to adjust the applied voltage to the part. To that end, I have purchased a professional gun system (at six time the amount of money as the Eastwood gun) that has this ability along with a voltage pulsing option that automatically modulates applied voltage when activated. Dual air pressure regulation values are adjustable to prevent wasting of expensive powders, and manual voltage adjustment capability is also offered.

I guess the take away from all of this is that original start-up investment is high, but future jobs and the flexibility offered look to promise to be an advantage. Another added use for this equipment would be finishing aluminum parts like heads and intake manifolds. With the dual application of chrome and translucent powders a attractive and more durable finish (so stated) than anodizing may be realized.....More to follow....

 

[8EL]

So the professional gun system performed like the difference between night and day as compared to the hobby gun. It also conserves powder consumption by transferring more powder evenly to the target, less over spray, and less cleanup. As stated the start up costs are high, but would be quickly recuperated given the costs to have this work done. A friend has informed me that he recently brought headers in to be ceramic coated and inquired of the shop of the cost to do automotive rims, and was quoted a price of $360.00 per rim. Besides this there are no hassles with shipping or delivering the parts to the powder coater. You pick your own powder color from who you want, not where the shop secures their inventory....All this equates to saving time, which is also money. It took me about four hours to coat and cure the six wheels for my coupe....