I have some side draft carbs that have cast iron throttle bodies and I'd like to contrast them against the alloy fuel bowls. However I don't want to paint the throttle bodies. After a search on carb finishing, someone suggested Eastwood's Metal Blackening solution. Has anyone tried it? Would it be somewhat resistant to gas? Caswell also makes a Black Oxide kit and if anyone has tried that I'd like to hear the results.
I have used the Caswell version. This requires some work. First, the part has to be zinc plated. Then it is oxidized by their black chromate solution. Unfortunately, cast iron can contaminate the zinc bath. It also requires lots of power, so a 5 amp rectifier that i would normally use has to be swapped for my 220v (input) 30a model. The only time I do this is for a 100 point type restoration. On other carbs I build, I powdercoat with matte black when the base is requested to be black. It is cheap, fast, and seems really durable. Tom
I have used a cold chemical blacking compound on components, the type used on stuff like metal tooling, but this is not very durable and needs to be kept lightly oiled. If you are avoiding paint because of the thickness, what about using one of the black high temperature cylinder barrel paints? They appear to be very thin (dimensionally) but when cured are very durable, and usually petrol-resistant. The curing is the down-side as they would want to spend quite a while in the oven.
I was previously pretty happy using a single stage automotive paint. The rattle can crap didn't hold up to the fuel. But I hate cleaning paint guns after each small job. I have a cheap HF powder coat gun that is dedicated to the matte black. Haven't had to clean it yet. Almost as convenient as a rattle can.
Thanks for the replies. I didn't realize the Caswell kits were so labor intensive! As for the paint or powdercoat route, I guess I was thinking about something a little more "raw". Maybe I'll just spray some Gibbs on the cast iron body and call it done.
The Caswell kits replicate real industrial processes with materials that are not heavily regulated. They are high quality and work well. They are not short-cut methods like maybe you find with some of the home restorer stuff. Don't get me wrong. Eastwood makes decent stuff, but it doesn't always have the durability of that used by the OEM suppliers. That's the trade off you get for ease of application.
1931av8 thanks for the insight. I spent some more time on the Caswell site today and you're right, they produce some high quality results if you take your time and do the prep work properly. Some of the customer examples are impressive to say the least. I actually ordered the Black Oxide gel kit which you can brush on rather than dip— which I preferred because I don't necessarily want to treat the inside of the throttle bodies. I'll let you guys know how it turns out. But of course now I'm tempted to get their Nickel plating kit too to plate the hardware and small brackets etc....
What about some chemicals, used for gun blackening or bluing????......................They would have to be oiled, occasionally....................It's low build, and would not hurt if it got in the throttle bore..............
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