Topic: clear coat problems, runs, milky colour

hi all, just recently starting doing alloy wheels, i start by putting the colour base down then i cure for 10 minutes, ( cure time is 10 mins at meteal temp) then i powder coat the top colour, back in the oven for 10 minutes at metal temp, then i tried applying clear coat,  now it came out with a milky colour in places, and lots of drips, i take it i put far too much on, which is hard not to when the wheel is hot, should i clear hot or cold? and how much clear is needed for a glossy shine, is the amount i applied the reason for the milky look and the runs and drips, also can i wet sand the drips or do i need to sand back and recolour?, thanks for any help




Re: clear coat problems, runs, milky colour

It definitely looks like you put too much total powder on.  I can't say if you are using too much base, color, or clear.  What does your powder supplier specify for ideal thickness?

The level of gloss in the finish is typically a quality defined by the powder itself, not by the amount of product applied.  Once you reach the minimum amount of powder to cover the surface to the recommended thickness, adding more powder will not give you any  more shine.  It may even reduce the shine.  Most powder coating shops that specialize in high-gloss finishes will wet sand and polish the final coat.

You could try to sand down the drips, but if the drips go down to the base or color layers, you will have to strip the powder to base and start again.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC