I have an aluminum cylinder head that I would like to paint to match the rest of the engine which is a gun metal gray.
Do I need to paint it with zink chromate first or can I simply use the engine paint from the rattle can ?
A friend of mine is into homebuilt airplanes, here are the steps he uses:
(i) Wash/degrease with detergent and warm water.
(ii) Scuff up the part and remove any flaking or bad surface with a wire brush or sandpaper.
(iii) Wash again with detergent and blow dry.
(iv) Wash with 50% white vinegar and water to etch the bare aluminum and blow dry.
(v) Shoot the bare metal with a thin coat (so thin it's translucent) of Zinc Chromate soon after drying to preclude further oxidation of the bare metal.
(vi) Shoot with 2 coats of the final paint. finished!
Scratch up the finish lightly with sand paper. clean off with compressed air and a solvent (I use Xylol). Go get some etch primer, but make sure it is high temp enough to handle your application. Shoot on the etch primer, let dry, and scuff lightly with more sand paper (400-600 grit). Clean off good and repeat the process to get even coverage (no solvent this time). Spray your finish on (again, make sure the finish coats can withstand the engine temps), then let dry. Repeat the finish coat process and allow to fully cure before using on engine.
Frank, i cleaned my Z heads w8ith lacquer thinner and made sure there is no grease,oil dirt and just painted with high temp paint right out of the can, ten years on one with no lifting or flaking.
Like Rick I finally painted my Z with a can of engine paint it looks great. Didn't do any special primer or cleaning except degreasing.
Frank did you read the thread about Henry Speaks?
I did some like Rick and Gene -- just clean them with some solvent and spray with engine paint, same as the rest of the engine. No problem.
ya, I know I bent the rules Model A green
green just feels summer timiey
If you want a real snazzy color you might try this (Day Glo Orange!:
It seemed to go on the bare aluminum just fine from a spray can of Krylon (FL-9). It is flat, so I then put a coat of acrylic lacquer clear coat over it. Turned out good. We'll see how it stands up to the heat. I will probably do the whole engine like this...It's for a speedster, so the Restoration Police can't arrest me!
Slight correction - the spray I used was PlastiKote NOT Krylon. I need a senior moment pill!
Jon, suggest you highlight the RAJO letters with some black or silver so they pop out. Looks Cool!
Total OT thread drift - Probably OK due the fact that it is Veterans Day.
Taking about zinc chromate reminds me of a Navy experience I had in 1971. I was serving aboard the USS Trigger (SS 564), one of the last of the diesel submarines. We were finishing overhaul at Hunter's Point in San Francisco. It was time to take the boat out in the bay for a trial run.
The superstructure (the part above the water line) was aluminum. It was wearing a coat of zinc chromate in preparation for it's black finish paint, which was scheduled to be applied the following week.
We had made our first dive and were testing systems and fixing minor leaks when the captain, who was on the periscope, said there's a pleasure craft off the port bow in distress. We surfaced to find 3 guys in a cabin cruiser out for a fishing trip, out of gas and drunk on their butts.
We didn't carry gasoline on diesel submarines, so we radioed the Coast Guard and stood off until we had the cutter in sight and were sure they had the distressed craft in sight. We then waived off, submerged and continued our trial run.
Thinking about it later I realized those guys would show up home probably still a little drunk with no fish, tell their wives they are late because they ran out of gas and were rescued by a green submarine. I bet they haven't been allowed go fishing since!
Like your idea about the RAJO letters. Hmmm, maybe white, since I am doing the speedster in Day-Glo and white?
Right, I did my Z Head and the made in USA in highlight. Looks good