Hi, I’m new to powder coating. I did a few part with no problem. But yesterday I tried to do a second coat over a motorcycle rim that I powder coated last week. The first time it work fine but it had some dust at some places. So I wet sanded it with a 1500 to remove those defect. I cleaned it with thinner and tried to powder coat the second coat. It doesn’t worked. Some places had no adhesion. So I sprayed the powder out of the rim and I removed the wire I used to hold the rim. I used a wire wheel on a drill to removed the powder coat overspray inside the rim where the tube go, to be sure I have a good ground. I carefully cleaned it again with acetone this time. I tried to spray it again. It doesn’t worked. It look like the powder hold well where I sanded through the first powder coat and does not hold well over the places where there’s powder coat from the first coat.
Is it normal? DO I need to remove all the first coat of powder coat to have an even coat of powder? I tought that it was possible to do that but it look like if the surface is not even all metal or all powder coat, it can’t be done. Is there something I do wrong? Do I need to spray it like that, bake it and once done do another equal coat or I really need to remove all the first powder coat?
Here’s what it look like when I spray it. The lighter spot is where there’s powder coat from the first coat and the darker spots is where I sanded it to metal.