Where the
world gathers for metal finishing
Q&As since 1989


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Carburetor re-plating / re-coloring

RFQ: Need instructions and chemicals for recoloring antique automobile carburetors. I have been told that the EPA has made this process too expensive for most small rebuilders. I made an inquiry to EPA and was told that they were not concerned with a private party doing a few dozen carburetors for their own cars. If you can help I will be happy to accept collect calls or fax. If you are a chemical supply co., even better.

Duval Lee Kugler
hobbyist auto restoration - Visalia, California, USA
2004

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

Antique carburetors & parts on eBay (affil link)

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Q. I would like to know the chemical process for recoloring carburetors to the original yellow dichromate finish. I am restoring an older Cadillac at the moment.
Thanks,

David Nash
Industrialist - Seattle, Washington, USA
2005

Q. Good to have you here, Gene. You are the guy who I'd like to ask a related question of! Some have claimed that it is not possible to get a decent look from simply re-chromating a carburetor but, instead, it is necessary to zinc plate old carburetors and chromate the plating. From your experience is this true, untrue, often true, or what? Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Q. I am restoring a 1930 Model A Ford and would like to restore the Tillotson XF carburetor to its original appearance. I believe it is made of zinc, and the finish has more of a gold-ish dye (almost transparent) look than a painted look.

What kind of finish is that called, and where would I go for help to restore it? thanks!

Andy Stenklyft
hobbyist - Roseville, California, USA
September 19, 2011

Ed. note: Please see Gene's next reply

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Q. I restore 30's era Fords, and want a method of anodizing the pot metal carbs back to original, off gold color, almost an olive drab, what do you recommend?

Bob Dickson
auto restorer - N. Chelmsford, Massachusetts
March 6, 2008

Q. Gene, Do you restore carbs for others? Thanks, Wes Wilt - Greenville Ohio February 3, 2024 A. Hi Wes. Gene's posting was from 15 years ago, and his job is/was supplying chemicals including chromate to plating shops. Sorry, we don't facilitate posters doing business through this forum ( huh? why?). Please try google for carburetor restoration (google was once an incredibly efficient technical search engine, but is drowning in commerce). Thanks! Luck & Regards, Ted Mooney, P.E. RET Striving to live Aloha finishing.com - Pine Beach, New Jersey

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Aluminum smut corrosion

Q. I have applied chromate to (2) carter AFB carburetors: The process was as follows:
1.Cleaned the carburetors with spray carburetor cleaner [on eBay or Amazon] followed by stainless steel wire wheel cleaning/buffing to a gloss finish.
2.The carburetor housings were dipped in PPG DX533 [ed. note: phosphoric acid based cleaner, brightener and pre-paint conditioner for aluminum] (1 to 3 mixed with distilled water) for 2 minutes. When the pieces were removed they were dark gray. The dark surface could be wiped off to some degree when wet.
3.The parts were then rinsed in distilled water and air blown dry with clean shop air.
4.The parts were again wire wheel cleaned using the same process as prior to the DX533 dip. The surface after this step was noticeably brighter than before the dip and looked like new aluminum.
5.The parts were sprayed with carburetor cleaner and air blown dry with clean shop air.
6.The parts were then dipped in PPG DX501 [ed. update Feb 2024: this is a hexavalent chromium chemical, and probably not available anymore] (clear chromate) (1 to 1 mix with distilled water) for 1 minute.
7.The parts were then rinsed in distilled water (separate tank than the DX533 cleaner rinse).
8.The parts were blown dry with shop air.

The parts have slight to moderate yellow color variations but look good and have a moderate shine to them.

My questions are as follows:
1.There are some ports in the carburetor parts that could not be wire wheel cleaned prior to the DX501 dip. Most likely the "smut" is still on the surface of these ports. If so, can this pose a long term corrosion problem?
2.Should I have de-smutted the parts in a nitric acid bath or comparable de-smutting solution prior to final wire wheel cleaning/buffing and the DX501 dip?
3.If I de-smutted the parts would the surface finish end up being dull, i.e., matte or would it maintain the luster similar to when they were wire wheeled?

Randy Villeneuve
Engineer (P.E.) - Amherst, Virginia
August 20, 2013

I am working on carbs for a 1981 Yamaha xv 750. I dipped one in a solution of muriatic acid. This was supposed to just clean the gummy stuff off but it took all the plating off and left the smutty crud. Did you ever find out how to remove it from the small passages inside?

Mark Gasser
- Columbia falls Montana
January 30, 2023

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Q. Hey guys, on a related note I'm looking into restoring an old Solex carb I picked up at the junk yard. I'm doing this so I can learn more about the carb, but mainly to start getting good at restoring the finish.

Here's a picture of the carb:



Basically, I'm wondering about how you can tell what the different compositions of each part are? I'm seeing a lot of references to zinc and chromate and polishing and such but I can't tell if this carb is made of any of those.

Thanks!

Evan Ruff
- Atlanta, Georgia
September 24, 2013


Q. I do this without the nitric step. I would like to buy the nitric but don't know a source for small quantities at this time.

Donald Dorfman
- Edgewood, Washington, USA
July 31, 2018

Carburetor cleaning and refinishing has been a perennial subject. Please see also --