Quote:
Originally Posted by jpmassey
I need some help, this is driving me nuts.
I am powder coating new sheetmetal and I can't get a chean finish. 99% of the surface looks great, and then there is a few blotches of bubbles. I am using caswell's super wet black.
My process:
-Sand with 80 grit (not removing the scale, just smoothing it out).
-Soak in acetone for a couple minutes, lightly wipe down with a soaked towel.
-Outgas for 20-30 mintues @ 450*
-Cool to under 200*
-Soak in iron phosphate for a few minutes. (Preheated to ~90*)
-Soak in distilled water for a few minutes
-Hang up
-Dry in oven
-Shoot at about 200*
-Heat up for about 10 mintues (monitor temp with gun)
-Cure at ~400* for 10 minutes
-Cool in oven for another 10 minutes
I use latex gloves for touching.
Whats wrong!!! I have to do alot of these by the end of the week.
Thanks for any help
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out gassing is usually not needed for steel, aluminium is a porous material thet s why it needs to outgas .
cleaning with acetone is ok but the towell could be a problem , it can leave small lint particles on the metal.
contaminated powder could be a problem
moisture in the air line or oil in the air line is a major source of problem
dust in the air or on you or your clothes could also be a source of problem
if you are sure they are bubbles and not dust i would bet on moisture or oil in the line
