Technical Don't Alodine Your Carbs!

Fun story time(too long as I'm in a rant!):
I am rebuilding some abused and neglected (OT) Weber IDA3Cs for my FIL. Already over $600 in parts(out of pocket) and plans to replate the other saveable parts, I thought I might hit a home run and refurb the bodies as well. A matching set of rebuilt Holley 94s on an EM manifold have been sitting awaiting the RPU project for a while so why not "test" with those first. About a $100 risk rather than $6000.
What's that gold coating on carb bodies? Certainly nothing like chromate or any other post plating stuff. Must be Alodine, right? Must be. FYI, Alodine is a passivation process for aluminum on aircraft parts. You clean, dip in etch solution, then soak in Alodine. Issue: AC parts are always of known makeup - typically 2424 or 7075. Carbs are cast zinc pot metal, Zamac, or whatever.
Stripped a 94 down, cleaned well in the US cleaner and gave the parts to an IA buddy with 55gallon drums of the stuff. He said he had to play with the parts to get a result but that the factory surface "flash" coating just dropped off. Not sure if "playing" was etching too long or what but here are some before and after shots. We are buds and no foul at all but I should have passed another carb rather than that of a tight rebuilt one. Should be able to cobble together another to work out.

Started as this. 80s-90s looking painted linkage but all new gaskets, butterfly screws PV, and super tight. Base plates were obviously blasted at rebuild so maybe that contributed.

Parts after cleaning. Not in bad shape at all:


Here are the pitted parts after:


I dragged a file here so you can see the pitting:


Don't be as smart as me!
D

 

Happened to a few VW guys I know too. Zinc is funky stuff.

 

Glad I didn't "test" Alodine with the 46IDA3Cs!!

 

I would suggest spraying with cerakote. It's very thin, very durable. and available in a wide range of hues.

 

How long did he leave it in? When I did mine, I cleaned, soda blast, cleaned, washed and let dry and then 30 seconds in Alodine, water dip and let air dry and they looked great, no pitting.

 

I think in the dip too long a period of time . Really bad bad ones I dip in thinned Muriatic Acid for about 30 seconds at a time , rinse , dip again , rinse as needed until spotless . Soda blasting works wonderful also , but still need a dip to clean passages

 

Would be interesting to know what prep dip he used.
Pics look like if they were Alodined, it must have been the clear version, as there is not really any color to them.

 

I thought so too. Could they have just used a chromate dip on the new zinc castings. As you can see this were already very clean and, in retrospect, the perfect patina(and one of a matched pair). I had not media blasted first. Shoulda left that one alone but I was testing to see if I could replicate the factory "yellow" finish and then do the Webers.
He thought the etch would remove the previous coating. Both this etch and Alodine are 25yrs old and have weakened over time. I am assuming he wasn't getting the reaction he expected and maybe then left it in the etch too long.

 

So you used no acid etch before the alodine?

D

 

Alodine has a shelf life of something like 3 years once opened.
Colored Alodine is 1205?
Clear Alodine is 1005? Or something like that without looking.

 

Apparently the specified 25yo etch didn't suffer from the same shelf life limitation.

 

No, I followed the instructions and was pleased with the results…

 

May I ask what brand, where you got it, etc? From my understanding, in the aircraft industry, it's common to "etch and Alodine" as the process. Just trying to learn here.
D

 

Search Alodine here. You will find some good discussion on process.
Aircraft Spruce is where I got mine. I plan on using some phosphoric acid as a final prep dip prior to the Alodine.
Started with plain old vinegar for initial clean up.

 

So were the Webbers $600 or $6000?

 

Thanks for all the info. Any pics of the Alodined carbs you guys have done?

Fortunateson, Google Weber 40IDA3C or 46IDA3C (which is what I have). Even used, and with unknown issues, they are thousands! Rebuilt they are in the $6K and above range. This is for original Italian-made and not the repros. I'm in over $600 just in replacing ruined parts from neglect and prior "mechanics". Bent throttle shafts and plates, rotted air screws, etc. They are pretty awesome but off topic for sure. Not intended for a hot rod. They are for a P****e. Surprisingly it ran fairly well but quickly showed itself as a fire trap.
I will NOT be Alodining these Webers without a lot more experimentation. Just never thought you dipped in Alodine without an etch first. I think maybe these Holley parts were overdone in etch in order to get rid of the remaining factory "gold" for a "best finish". Differing expectations along with lack of comms. All on me.
I might dip some Holleys once I find some decent replacement castings and maybe skip the etch. I have a pair that will work but aren't matching markings. Not a big deal.
D

 

Would have to check my Weber book, but kind of recall Webers were die cast aluminum.
That is what Alodine is for. Die cast Zinc turns to a olive drab/military green color.
When using Alodine on aluminum, the stuff I have seen turns real gold with a short dip time.
This is the stuff you are after. Made by the same people that make Loctite products.

 

Hmm. Thanks a bunch. I think I'll rebuild without dipping for now. Do you know if all old finish must be removed first? I fear the attempts to remove might be the problem area.
I was given the car by my FIL, took it overnight, but found it puking fuel the next am before I could drive it home so I had it trucked back to his place 7mi away saying, "I just don't have time for another project right now." I think it hurt his feelings a bit but I ended up pulling the Webers so he didn't burn himself up taking it to "his guy".
Thanks again,
Dave

 

Aircraft Spruce in Corona, Ca…..

 

https://www.aircraftspruce.com/

 

I’v used Magna-dine on magnesium
Maybe they make a Zinka-dine?

 

https://caswellplating.com/yellow-chromate.html

 

Yeah, yellow chromate I can do but afraid of what the prep does to various unknown castings.

 

If you know the manufacturer and model
most data sheets can found on the inner web
just ask google, very smart guy that google dude is

 

Why experiment with $$$ carbs??? Clean them up, get them working right and run 'em. Or.... sell them and get an induction system you can work with.

 

Ok, Alodine 1201 is very strong in concentration,it should be used after acid etch cleaning with a chemical called gibson 528.for best results, It is designed to be used as said above for 30 seconds max in full concentration,not bye the colour its burning into the part,yes its highly combustable so dont leave it on rags or paper sitting around in heat.There are other less agressive versions ,600 and 1000 series Alodine ,they are clearer in colour and favoured for protecting alloy in electrical bonding circumstances,94,s are my prefered carb and ive Alodined dozens of them and never had it eat a carb as posted,also used it for over 30 years in the aircraft industry,this i believe is mis information and the op,s post is a corroded carb ,its obvious too the eye if you work with corrosion and alloys full time.Also i think youve posted different pictures of different carbs,ones marked holley and others clearly 8ba ??? how does your carb become more orange after cleaning?holley carbs ive never seen with ford 8ba markings,i think youve got yourself confused and mixed up your pics n carbs

 

Yeah, not sure. I had pre pics of each of three carbs so that first one is likely another carb. The disassembled castings are the only one etched and ruined. I think the "orange" is perhaps where the Alodine did take where the corrosion wasn't so bad.
'28phonebooth, I'm not experimenting on the $$$ Webers - just on that one 94. BTW, what other induction would I put on a 3.0 with cams? Just too OT to show those.
Apologies if my pics and/or explanation is confusing.
D

 

I did these with Bonderite/Alodine. I was happy with the results...I experimented with short dip times on scrap carb pieces until I got the color I wanted. I don't recall how long it took...but it was only a couple minutes or so.

 

I've done bunches of them, before treating them I media blast the existing coating off it so the raw zinc in exposed and then treat the bodies with alodine and the cast iron baseplates with 'Tool Black'
the photo is one of a set set of Carter YH's I am doing 'as we speak' The alodine I have is clearish, I've been using this for a least 15 years and those carbs look like I just did them.

 

The clearer series alodines are used in exposed aluminium on aircraft ,fuel tanks and also leading edges of wings and nose cowls of engines,where no discolouration is wanted. if that gives anybody any ideas where they can use it on their cars besides on carbs. the above two posts are the results you should get.Also note For those using it at home,Alodine has a shorter life span openly exposed to air in containers and becomes weaker ,almost diluted and its life span becomes weeks,if you are dipping parts washing them off and putting them back into alodine too get them darker the water will dilute and shorten its life span considerabley. alodine does not discriminate against a corroded part it will still coat it if cleaned properly and corrosion is removed,thats one of the reasons its used, Lastly Alodine 1201 while great for carbs is almost never left unpainted in the aircraft industry,its a coating that helps paint bond too alloys,perfect for prepping and painting alloy bodied cars,We have also used Alodine 600/1000 too prevent tarnishing corrosion on magnesium spindle mounts and mags,and for paint prep on those