Inliners International Forums General Discussion Tech Tips Restoration/Preservation NOS Carburetors

Greetings . . .

I posted back at xmas time that I had scored a pair of NOS carbs for my 216 build. Trouble is that while they were 'new' items they had some extensive oxidation damage from periods of damp storage in their 60 years on the shelf:



The 'white rust' was everywhere that there was gasket to metal contact. Both carbs had lost extensive amounts of plating along abutments - but most of the finish remained intact.

I tore both carburetors down to the bone and began researching what to do about this 'white rust.' The internals these NOS carbs were essentially spotless:

there was no reason to even order 'rebuild' kits! The internals were simply sprayed with carb cleaner and then lubricated with silicon for reuse.

The zinc bodies retained a lot of the original finish. I began researching techniques to check the 'white rust' but retain as much of the original finish as I could:


I found a non corrosive product called EvapoRust that dissolved the white rust oxidation without the metal loss typical with etching that goes hand in hand with using acids:

I was amazed at how a 24 hour soak could eliminate the oxidation without damaging the rest of the metal. Where there was no oxidation the EvapoRust left the plating intact:

However, this cleanup turned out to be fleeting. Left to open air the raw zinc bodies turned white again. Some research on the web revealed that zinc is highly reactive with oxygen and requires 'passivation' in order to stabilize the surface. I found several threads online discussing the use of Alodine:
Heinkel Alodine 1201
The acid in the Alodine solution partially stripped the existing chromate finish. But Alodine contains hexavalent chromium so it replaced part of what was stripped with a new chromate coating. This 'finish' was allowed to dry for a week and then was sealed with NAPA Silicone spray:


There appears to be a limit to the number of links that one can attach to a single posting so I will have to reply with a follow on to continue.

regards,
stock49

Greetings . . .

Here are some before and after shots:

the gaskets were 'restored' by soaking in NAPA silicone spray followed by WD40 before installation

when I first saw the white rust I was worried that I would have to strip all of the finish to get rid of it . . .

after rebuilding the results show a good bit of the original finish remains without looking restored:


regards,
stock49

Thanks for the tips. Where did you get the Evapo-Rust? I found a website and I see that Summit sells it. These look like two good products. I have some Zeniths that need some help.

Hi Beater . . .

I bought the EvapoRust at Tractor Supply. They sell it by the gallon.

stock49

The white rust as you call it is Oxadation, That is what happens to Alum.espcaily any type of cast alum.cast alum will do this even if it has been plated over It just takes alot more yrs for it to do so.We use to use that stuff in our restoration shop.It does work Great.

Hi Twisted6 . . .

So you think the oxidation was inevitable? No matter how these old pieces were stored it would have happened anyway?

Because of the proximity of the oxidation to the gaskets I surmised that they had been subject to damp conditions at some point - which the dried gaskets absorbed and held on to - giving the water time to work on the finish, expose the zinc which then oxidized.

It's academic at this point. They are rebuilt and ready to go.

stock49

It would corrode eventually, if you packed it in a sealed container with something to displace the oxygen (argon maybe ? ) it would last longer.

Right at some time in point it would have happened anyway.ANd with it beening mostly at the seams (gasket area) is because they do (atract) hold OR can hold moisture. Just because of the paper/card board type material they are made of.

Alodine is available thru Aircraft Spruce. They also ave many other "parts" which maybe usefull in our projects..........

Yep. That is where I bought the stuff. Aircraft Spruce.

Do be careful with Alodine, especially the etch, it is acid after all.

I get evaporust at Harbor Freight. It worked great on my heater an a couple of fans. ( pics here)

Nice thread ! .

That is a 2BBL carby , not a 216 NOS one , no ? .

I have a Carter W1 216 carby in the crumbling Delco box , it shows little corrosion , maybe because I'm in Los Angeles , it's a desert here , very dry air ? .

Hi Nate . . .

Indeed these are 2 barrel carbs - Carter model WCD. They were designed for use on the small six found in the Nash Statesman.

I chose them because of their 3-bolt base (like the Stromberg 97 or Holley 94) but smaller venturi.

regards,
stock49

BTT

Does Evaporust remove paint also?

Just noticed this question. In my experience, this product will not harm paint that is well adhered to clean metal. But if it is paint on top of rusted metal - it will lift the paint when it dissolves the rust underneath.

It had the same affect on chrome. On pitted pot-metal the chrome flakes off where ever there was rust underneath - but where the chrome plating was 'water tight' to the base metal it remains in tact.

What I like about it is that you can't overdo it (unlike naval jelly). There is no acid. Once the oxidation is gone the solution stops working. I have left things soak in this stuff for a week . . .