Topic: Painting cast alum. engine parts

[Red750K1]

So I went easy this year and just painted with 500 degree engine paint instead of polishing. . . problem is the dam paint will peel off after only 1 or 2 weeks then you have to "touch up" those parts again. It still peels even when roughed up and cleaned with acetone. I decided to try something different last weekend and it worked great!    Aluminum auto rim paint! Its the kind that you're supposted to bake on so I figured it would take the temp of my CB750 and it has so far. No chips or peels, and the best part is it has a little tiny bit of fine metal flake so it looks much better than the "cast alum" 500temp engine paint. I'm happy, try it out!

[ZetecOwns]

Very cool. What brand did you use, if you don't mind me asking? How exactly did you bake it on?

Oh, and of course, any pics?

[81cb650C]

VHT Engine Enamel works wonders.  I painted my engine 2 years ago and have never had any peeling or fading of the paint.  The paint also uses the same concept of curing the paint with the heat of the engine.

[Terry in Australia]

Sadly a lot of really good paint is vilified by bewildered painters when it doesn't stick to aluminum. The truth is that aluminum is a tricky thing to paint, and benefits well from "etch priming".

The "Etch Primer" chemically etches into the aluminum and provides a "key" for the paint to stick to. You don't need a lot, just "mist" a coat over well prepared cases and you're good to go with whatever brand of engine paint floats yer boat.

Here in Oz my favorite brand is "Powerplus aluminium", it looks about as close to the OEM Honda color as I've seen and covers very well, but this brand is getting harder to find, so I'll try some of the Holts wheel paint, seeing that "Powerplus" and "Holts" paints come out of the same factory, and I've heard good things about the Holts wheel paint before. Cheers, Terry.    

[Ichiban 4]

May have said this on another post..

But Honda itself..paints almost all the aluminum on their restoration bikes..also on new bikes.   They do not etch or prepare surfaces especially (I've seen them doing this @ motegi in their shops).   What they do-do however..is to make absolutely certain to get all oil and grease off before painting.  @ Motegi shops they vapor blast all parts before painting.

If the paint is rated for high temp applications..especially the silver-aluminum cylinder types of paint..the aluminum particles in the paint actually fuse somewhat after being heated (think the "fusing" temps are around 500 F).  So concerns about peeling, flaking are not so much as with regular paints with only carriers/solvents and pigments..that can degrade with heat.

I can say from own experience..that after cleaning cam covers, heads, etc. first by using Gunk and power washing..then with Q-tips and acetone (for tight areas)..then using designated cylinder paint (either automotive engine-header type..or regular bike cylinder paint)..that the paint stays on for years..and many many miles after application.   Have painted air cooled bike engines for many years..and only had to repaint after it burned off after years of use.   So..this concern is not something that should be very troublesome..when done with reasonable care.

Mattane

[Terry in Australia]

Well I've just stripped and repainted a K6 and now a K2 engine Ichi, and I chemically stripped them rather than blasting, and guess what? Under the layer of OEM silver paint was a layer of etch primer?

It was much harder to remove than the OEM silver, but it looks just like the high zinc stuff that I used to refinish them. I don't know about the cylinders and heads, but I'm convinced that they did etch prime the cases in the factory. Cheers, Terry.

[aptech77]

PJ1 or VHT works well!