Cleaning soda before painting

I have a buddy that just did his last winter in powder coat. It looks really good. He brushed the coating off the tips of the fins then went back later on and layed stripes of yellow high heat paint on the tips with a brush. Looks killer. He also added a oil cooler and he can let it idle all day and it doesn't over heat. Thinking about letting him powder coat mine this winter. He does it in a kiln he made. Us country folk get it done anyway we can..lol.

In principle black paint would cool the motor down more effectively than if not painted or painted with a light colour. It radiates the heat it has absorbed outwards which is why it feels hotter. The same principle why Bedouins in the desert have predominantly black (or a very dark colour) tents and wear dark clothing ......

Gm did a study 30-40 years ago from what I remember.
Anyway they came to the conclusion that black was the best color to paint a motor for heat disipation, as far as I know gm still paints all their crate motors black for this reason.

Shdwdrgn wrote: With that said, it seems like a good idea to try to stick with solutions that result in a thinner coat, so the Gun-Kote like DoctoRot suggested would be a great choice. I just wish the stuff wasn't so expensive!!! My initial search puts it at about $41 for a 6oz spray can.

considering Ma Kaw painted several of their engines black from the factory it will not over heat unless you put a TON of paint on.

Also i just checked KG coating website and its $18 for a 8 oz. bottle of the original 2300 series. dont know where you saw $41, but i would buy it direct through them. 8 oz. should be plenty to paint your engine. BTW you will need a oven to cure the paint and a cup gun to spray it. If you go this route, DO NOT do this in your home oven. it states on their website that their is a small amount of lead in the black and green paint, not something you want around your food.

Yeah I did find some better prices after looking around a bit more. I also found another product called DuraCoat which is supposed to be similar quality but doesn't require the oven curing (although it takes several weeks to fully cure). That one has a hardener with it, so the curing is done by a chemical process rather than heat.

Either way, you really think 8oz is enough for a full engine?!? I used up over a full can of spray paint just for covering the carbs and brackets, and what peeled off still seemed pretty thin. Then again, maybe it was because of the soda residue that I was having trouble getting a good even coat, and thus needed to use so much.

In the end, I only have a low-output compressor and no decent spray gun. I do have an air brush around here somewhere, I suppose it might be worthwhile to try and dig that up again. Since I don't have anything *but* my kitchen oven, the DuraCoat might be worth looking in to.

Shdwdrgn wrote: Yeah I did find some better prices after looking around a bit more. I also found another product called DuraCoat which is supposed to be similar quality but doesn't require the oven curing (although it takes several weeks to fully cure). That one has a hardener with it, so the curing is done by a chemical process rather than heat.

Either way, you really think 8oz is enough for a full engine?!? I used up over a full can of spray paint just for covering the carbs and brackets, and what peeled off still seemed pretty thin. Then again, maybe it was because of the soda residue that I was having trouble getting a good even coat, and thus needed to use so much.

In the end, I only have a low-output compressor and no decent spray gun. I do have an air brush around here somewhere, I suppose it might be worthwhile to try and dig that up again. Since I don't have anything *but* my kitchen oven, the DuraCoat might be worth looking in to.

You did't see this kit? DuraCoat Shake 'N Spray

Wow, and only $35 for 4oz of paint -- what a deal!!! :woohoo:

For that kind of cost I could buy a new air brush. Eesh. Ah well, I've got some time before I can get the old paint stripped off, and it sounds like I need to at least find some sand to hit the surface with before I try to paint. I know the little blaster I have can take 220 grit, I'll just have to see what I can pick up. And it sounds like acetone is a good cleaner, which is great because I have a couple bottles sitting on the shelf not being used.

I guess the real question is, are any of these finishes really worth the additional cost over regular paint? Obviously I screwed up by not cleaning the carbs after soda blasting, but if I were to do a proper sandblast and clean, I'm starting to think that the regular engine paints might stick just as well?

In all types of painting it really comes down to how well you want it to hold up over time. Better prep, better paint, and better application will look no different than the cheap easier ways initially, but depending on the abuse you throw at it the cheaper stuff will deteriorate faster. Most folks that paint their engine are probably not ever going to put lots of miles on the bike, so it will hold up and look good for years. I first painted my engine with PJ1 engine paint after cleaning the crap out of it, and was dismayed why i found i could scratch it off with my fingernail because it had no "tooth". I then i went all out because the thought of repainting the engine down the road kept me up at night. You have to decide what level you think is worth the hassle. I think a sandblasting and painting with a regular engine paint will probably be satisfactory for you. BTW you can get a cheap HVLP paint gun at home depot for $50, and take your cases or what ever to a powder coating place and they will cure them for you.

There's also an old hot rodding myth that if you paint the underside of an intake white, the white paint will help it stay cool cause white will reflect the heat. In all reality, it would be adding an insulator that would keep it cooler. But with aluminum, which is what the carbs and motor are made of, you should also be using a mildly corrosive surface prep, like alodine or self etching primer, since aluminum isn't porous like steel and iron are. But gunkote should be ok just so long as you prep the surfaces with an abrasive media like blasting grit or sand paper. I'm not an expert by any means, but having painted an aircraft or 4 in the corrosion control shop in my first squadron, I learned some things about painting aluminum. Aluminum is tough to get paint to stick to.

60ratrod wrote: Aluminum is tough to get paint to stick to.

It is indeed. KG coating recommends that for aluminum it be anodized first, then painted. second to that is media blasting for prep.