Classic & Vintage - HELP ME Oxalic Acid PROBLEM!

Hey I PUT ALL MY CHROME PART IN OXALIC BATH and i notice 2 pieces are turning black!!

1. rear brake assmebly had little bitty spots of rust, and now im noticing their not going out, but i see black!

2. the MOULTON Kicks stand was rusty but had chrome, has now turned black in spots were it was rusty before!

3. sturmy archer 4 speed selectors sticker faded its paint! not that bad since i can still see it.

4. all parts still have the same rust as before! example, i steel wooled the handlebar and it cleaned up nicely, but had some rust that didnt want to come off, and still dont want to come off

edit, the wheels are not cleaning off at all...

im not sure, maybe my concetration is to low...i just added more, and still have faith :thumb:

WRK101 were are you!lol

I would not have gone the that route, but here what could have happened:

Chrome often gets fully compromised, so the steel will be exposed, that will turn black with the acid.
So, you were going to have to contend with that anyway.
Chrome often lifts around the point of failure, the chrome appears intact, but it has been lifted by corrosion. Not good. The acid just accelerated the problem.

ok, i can deal with black, just want all corrosion out. but ive seen result on others and never saw black. i mostly thought black was an electrolysis problem.

How long have you had the parts in the solution ?

Actually, chrome frequently has a layer of nickel plating underneath it. That might be what you're treating.

I also want to know how long you've had it in the solution, I had to leave my frame and work in the acid for 3 1/2 days before I was satisfied. I also saw some dark spots on the chrome where there had been rust, but it was more of a dark grey than black.

hey guys thanx for the replys! when i checked them, the parts had around 23 hours...16 with 2 spoons and 7 hours with 4 spoons...now they have around 6 spoons.....ive read about it all depending on the concentration..i just dont want to overdo the concentration of acid on water...i've handled it without gloves without any problem to my skin...of coarse i do clean myself with a lot of clean water after i touch anything.

The temperature of the water affects the needed time as well. Warmer makes the acid more reactive.

I've had parts that came out nice in 2 hours, and others that I've had to leave over a night or two. If you've got anything alloy - don't leave it in for more than a couple hours, or it will be tinged a yellow-green that is very stubborn to change.

i've handled it without gloves without any problem to my skin...of coarse i do clean myself with a lot of clean water after i touch anything.

You might want to get gloves. Somebody on here explained very clearly why it's bad to handle with your skin even though it seems fine. I don't remember the exact reason but I remember it made sense when I read it and have used gloves since then. I think it was something about the acid soaking through your skin and staying in your system so it adds up every time you handle it and can cause problems.

The temperature of the water affects the needed time as well. Warmer makes the acid more reactive.

I've had parts that came out nice in 2 hours, and others that I've had to leave over a night or two. If you've got anything alloy - don't leave it in for more than a couple hours, or it will be tinged a yellow-green that is very stubborn to change.


i dont deep my hand without gloves but i do handle everything else without gloves.

im not really sure what is alloy, im startimg to think the kickstand is alloy....not sure how can i find out?

...im startimg to think the kickstand is alloy....not sure how can i find out?

Most metals in bicycles are alloys technically. I should have been more precise and stated aluminum alloy.

Magnet test. If it sticks, it's a steel alloy. If not, it's a largely aluminum alloy. I don't recall whether stainless steel is magnetic or not, but if it's stainless, I would expect it to not get in a condition where one would be tempted to give it a soak in oxalic acid anyway.

Some stainless is magnetic, some isn't. Helpful, I know. Generally, the 300 series, are austentitic, and non-magnetic. The 400 series are martensitic, heat treatable, and magnetic. Both classes will have over 11% chromium, but the 300 series adds a healthy dose of nickel, but very little carbon, while the 400 series has essentially no nickel, and up to 1% carbon.There are more subtle distinctions, but that will get you in the ballpark.

yeah i guess i have to get home and get it out ASAP

thanx for the tip hope i dont damage the wheels...their not turnig any color not green not yellow nothing! no sing of rust going away...the rim has engraved E.A. i ghouthg that was england AVOn

i just checked on the parts shhh dont say anything!

got a magnet and checked, evething reacted to it...and the stand is getting a greyish color now.....hopefully ill be getting better resulst, i was so worried! the wheel is cleaning very slowly..patience is something im trying to cultivate, im very impulsive, i like fast results! but i understand, still its very difficult for me to be patient...

im growing some plants in hope that i can be a better parent once my GF has the Baby, i use the bikes to grow patience...

You can be a farmer and own bike repair shop.... IT AINT GONNA HELP. LOL

I always wear gloves, its just good common sense.

Warmer works faster, warm water or set it outside, cover it for safety reasons.

Dilute plus longer time works fine. I do 24 hours to 36 hours or so.

The only black area I have had is where the chrome was gone underneatth the rust (a small area on a rim).

+1 Keep any acid away from aluminum.

If that kickstand is galvanized (like many were) instead of chrome, oxalic is likely to be mean to it.

+1 I have not seen chrome kickstands, either aluminum or galvanized. I have put wheels in the bath with galvanized spokes. It has cleaned the rust off them. But clean galvanized spokes still end up looking dull and gray.

I have not dipped galvanized parts in oxalic on purpose. Not sure it is a great idea.

In terms of glove useage... I'd be more worried about soluble Aluminum getting into my system than the Acid. It's been linkd to memory loss, Alzheimers,............ and I can't remeber what else ;)

lol, thanx guys!

i guess some chrome was off the rims, because its not cleaning off, just no rust......so f it i think im done with OA for them

the kickstand is still underwater...the chrome is not going out, but all the rusty places are now black.......all other parts are right now white, good! today i will get most of the parts out since 2.5 days elapsed.....my patience is maxing out! lol

i use gloves to get the parts off the solution...but after i just use my bare hands to clean them.

im not sure this moultons had any aluminum parts


ive been trying to figure out if my rims are alloy or what they say: Dunlop E.A. England 3/5

In terms of glove useage... I'd be more worried about soluble Aluminum getting into my system than the Acid. It's been linkd to memory loss, Alzheimers,............ and I can't remeber what else ;)

Memory loss certainly isn't good, but with oxalic acid your problems may be more immediate (ref. this (http://www.bikeforums.net/showthread.php?t=505245&page=2)):



The link above didn't mention the LD50 for it.
"LD50 (LD50 is the Median Lethal Dose, which is the dose of a drug or chemical predicted to produce a lethal effect in 50 percent of the subjects to whom the dose is given) in rats is 375 mg/kg. So for a person about 145 pounds (65.7 kg) that's about 25 grams of pure oxalic acid required to cause death."

I'm guessing that 25 grams is about a heaping tablespoon or two.

The Health rating of 4 (cyanide is also 4, I think) is because all the oxalic acid you absorb/ingest will end up complexing with your calcium and will end up plugging up your kidneys. You can not excrete it. It accumulates as insoluble CaOxalate. That is why they rate this as 4, extremely damaging to health. So even if you don't take in the 25G needed to kill you outright, your kidneys might rot with a smaller amount or with repeated exposure.

Yes, it is a weak acid - the chemical term to indicate it does not ionize completely in water, unlike hydrochloric, sulfuric, etc. Acetic acid is also a weak acid. But unlike acetic acid, Oxalic is toxic to the kidneys.

So it pays to warn people when they use this!!! Especially using it around critters to which you do not wish an agonizing death.

you guys are scary...i will mention that Oxalic acid is present i nature in many edible plants and even candy......i dont think handling the parts will cause death...but i surely will be more diligent with this project of mine