Painting Ferrari Wheels

Sometimes I just want to give up and stop working on these cars. We stripped and painted these Ferrari 512 BBI wheels 2 years ago and they are already “popping”, where the paint is blistering and developing tracks under the paint that looks like worm trails in mud. After 25 years of use, the original paint was definitely in need of removal and on one of the rear wheels, the paint was blistering but not nearly as bad as after we re-finished them. Why is this a problem that needs to be diagnosed?

These wheels have lots of magnesium in the alloy and this causes the casting to be very porous and oxidize very quickly. When we paint these wheels, we chemical strip them, then bead blast the wheels. Next we use an acid etch cleaner mixed with water to scrub and soak the parts and rince heavily with water. The next step may be the problem, we bead blasted the wheels again to remove the surface oxidation, followed immediately by a wax and grease remover wipe and a coating in epoxy primer. Maybe the glass bead had contaminates that were forced into the casting?

Someone told me that after you strip and clean the wheels, you have to “bake” them to allow casting to off-gas and prior to sealing it off with primer. I am not sure this is the case because if they still have “gas” in the pores then they will continue to off gas immediately after painting them.

If anyone has any tips, I would love to hear them!

Painting a Ferrari Cast aluminum wheel