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Just reading through some other discussions and suddenly worried that I may have screwed up... I soda-blasted my carburetors, blew off the extra soda with compressed air, then painted the carb bodies. Now I'm reading that a thorough cleaning should be done to remove the soda residue. So what are the chances that the paint is going to start falling off when I get the carbs on the bike? Its been about a week and a half since I painted them, so I'm not sure what to expect.

were u able to clean the carbs w any carb cleaner before painting? I would think that it would hold up. gas on the carbs would peel away paint.

The biggest issue Ive had with parts that were stripped with soda blaster or paint stripper is that the metal is too smooth for primer/paint to stick.
I learned the hard way to rough the material up with sand paper before prime/paint

I didn't see a need for using carb cleaner or anything on them once I had finished. These carbs have been sitting outside for years, so most of any gas that was on them would have been absorbed and blown away in the dirt/dust. There were very few spots of noticeable grease, and those all cleaned up with very little work from the soda blast.

The soda didn't really polish the surface of the carbs. You could still see the original casting surface once they were cleaned up. And it didn't take much to paint them -- just a light spray to stick the surface, then several passes to get an even coverage. There's been no sign of wrinkling from missed oil residue, and I didn't have any problems with paint trying to flake off when I peeled the tape, so it seems like it stuck well.

What worried me most was that I didn't consider a powder residue being left by the soda, however I know most times spray paint is pretty good about encasing and soaking through any bits of dirt left on the surface, so hopefully it also soaked through the soda and this won't actually be a problem. At this point the paint should be pretty solid, so maybe I'll just spray them down with the water hose and see if anything knocks loose.

it should be ok. R they mounted on the bike.

Not even close to that stage yet. These were just the first pieces, everything else still needs cleaned and painted, and I need to rebuild the engine... I did hit them hard with the hose tonight, and saw no problems with paint coming loose anywhere, I'd just hate to have them sitting on the shelf for the next X months and only discovering there was a problem when I as actually ready to ride the bike.

Well the answer to the question is yes... all of the paint is falling off.

I pulled the caps and bowls today and used the soda blaster to do a quick tap on the corners so I could cover where the screws were before baking those pieces. Unfortunately, paint started coming off in sheets. So then I put them in the sink with soapy water, which caused even more to fall off. At least half the paint came off altogether, so I think the best plan is going to be cleaning everything completely again with the soda, washing them up in the sink, then try repainting again starting with a self-etching primer.

Ugh what a mess.

the soda does leave a light residue on the carbs. when i soda blast carbs i drop them into boiling water after to remove the soda residue, but why paint the carbs anyway? IMHO some things are more hassle to paint than worth the reward. If you clean the carbs really well and degrease before etching primer you will likely have better luck. I would recommend a solvent proof paint such as KG Coatings - Gun Kote. That way the first time you pop the bowls off to adjust something you don't have gas suck under the edge of the paint and ruin your paint job. just my .02

My original plan has always been to black out the engine. It's just a look I really like. I used some gas-resistant engine paint for the first coat, but obviously didn't get a good base to start from. That's $18 in paint down the drain, hopefully I get it right next time. I'll be doing the same thing to the engine later.

I have yet to see a high-temp self-etching primer. if you want real good adhesion on the engine a more aggressive media will be required. When i painted my cases I had them blasted with a 50/50 mix of bead and granite, then painted with gun kote which is not only solvent proof but extremely durable. gun kote is crazy stuff, its what the navy seals use inside their guns to prevent corrosion as it can be sprayed very very thin, and even acetone will not take it off once it is cured. I use it on brakes as well.

Does anyone have issues with the engine running hotter with a black paint. I wanted to do this as well with mine but have heard from some old timers that it will make a engine run hotter and take longer to cool off. On my carbs I used bed liner paint for the tops and bottoms and have had no issue with peeling. Liked it so much I did my entire frame with it. It gets a lot of compliments. Gives it that old school rustic look.

Based on what I have heard before (and after doing a quick double-check on google), the common wisdom seems to be that adding a layer of paint to the engine will increase the heat simply because of the insulative properties. And there seems to be no significant difference based on what color you paint the engine. The thought that black will make an engine run hotter or cooler is probably based on the observation that in the Summer sun, a black engine probably would stay warmer to the touch, but in the temperature range that actually matters, there would be no difference based on color.

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.