question on paint preparation of aluminum parts. since so many are using aluminum heads, timing covers & water pumps in rebuilds, what is being used to prep these parts for final paint. i've heard of zinc chromate being used for airplane restoration, but, i've also heard it is very hazardous working with it...
need some suggestions.

dal442

 

Cleanliness is the #1 important factor. No grease, oil, old paint, water, etc. Sand, or blast the parts, light scuff with a Scotchbrite pad, then either the zinc chromate, or epoxy primer, and paint. Etch primer will be better than regular primer, but not optimum for aluminum.
Any "good" paint product is going to be harmful. Use proper precautions!

 

Go to your paint supply store and get two products:

• surface etch for aluminum to remove the oxide film
• conversion coating to reestablish the film before painting

As Chop stated, you MUST remove all oils before starting this process. Many people do bead blast or sandblast the pieces before degreasing as extra ensurance.

 

Aluminum is very porous and any type of bead blasting is going to expose those pores more. That means oils can penetrate easily. After blasting you need to clean it thoroughly. Acetone and lacquer thinner are probably your best bets but I admit I use brake clean often and have had no problems with it although many report it leaves a residue.

 

Do you want to apply brush on paint or aerosol spray paint?