# Tell Me About Oxalic Acid



## mbstude (Sep 17, 2016)

First, apologies if this is in the wrong section. 

I just bought a really dirty "40-years-in-a-barn" 49 Schwinn. The paint looks great under all the grime, but there is some surface rust staining and most of the chrome has a rust coating. 

I've seen oxalic acid mentioned here but I couldn't find an explanation of the process in a search. 

I see that I can buy powder and crystals online cheaply enough. But, what do I do with it? 

If someone could fill me in with instructions on what works for them, I'd appreciate it. 

Thanks!


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## Greg M (Sep 17, 2016)

Here you go, just scale up for a full frame:


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## GTs58 (Sep 17, 2016)

Wow, over a pound of OA in maybe a gallon of water! I call that extreme and way off the ratio chart that it doesn't even compute.

This should be in the restoration tips section. Lots of info on OA there.


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## mbstude (Sep 17, 2016)

Thanks for the video link. So, it looks like it's a simple as mixing the powder with water and letting the parts soak.. Cool.

Is it safe for painted surfaces?


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## rickyd (Sep 17, 2016)

As mentioned above tons on OA in Restoration section. Also smarter folks than me mention red paint may turn brown.


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## SirMike1983 (Sep 17, 2016)

mbstude said:


> Thanks for the video link. So, it looks like it's a simple as mixing the powder with water and letting the parts soak.. Cool.
> 
> Is it safe for painted surfaces?




http://thecabe.com/forum/threads/rust-on-paint.67574/#post-606988

The short answer is "maybe" on paint. Certain types of paint and certain transfers will not respond well to it and may come off or change color. Other types of paint respond _very_ well. Red paints tend to be more suspect, especially those where the paint pigment uses a rust-derivative to get the red color. 

The acid crystals to water ratio vary from person-to-person. 

http://thecabe.com/forum/threads/oxalic-dip-question.80570/

Removing rust with 0000 steel wool and WD-40 is not as thorough, but may yield a more consistent result across the paint. Oxalic will get into the little spots of rust much better, but also cause the bare spots to become more prominent.


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## the tinker (Sep 17, 2016)

Do not use Oxalic Acid on chrome. Read the many posts in the restoration thread about rust removal from chrome.
Much better and safer and easier to use products available. If you only have a light coating of rust on your chrome parts a decent chrome polish will work wonders.   Do not use steel wool. If the rust is heavy there are several different brands of rust remover that you can soak your parts in overnight that will remove every speck of rust. Oxalic Acid will not remove grease and grime and dirt. It will leave a tough yellow coating on your chrome that may be just as hard to remove as your rust. Before you grab that steel wool and wire brush remember: your chrome plating is thin and already worn from age. You do not want to remove any more of it.
Oxalic acid gives off very subtle but harmful fumes that are barely noticeable. Only use outdoors.
Yes it is harmful to any paint that uses Iron Oxide in it's pigment. It will turn some, but not all reds pink or a shade lighter.
For the benefit of recent Cabe members that have not thoroughly researched the restoration threads I post these pictures of Oxalic Acid's results on badly rusted fenders soaked over night. These fenders were not cleaned up after soaking for the photo. What you see is photos taken immediately after removing them from the O.X. bath.
Remember that any acid that attacks Iron oxide will seep under the paint and "follow" the rust and may lift paint and chrome that otherwise would have stayed put.


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## mbstude (Sep 17, 2016)

Thanks for the replies, guys. I'm a big fan of Evaporust and I'll use that on small parts, but I'm wanting a more cost effective way to soak larger parts, like bike rims or whole frames if it comes down to it. After a few hours of reading tonight, I ordered a bag of citric acid and will give that a try. The toxicity of the oxalic acid scares me a bit. There's a lot of rusty junk around the shop so it'll be fun to experiment.

Mike, I came across your blog post while searching older threads on here. A very good read! I like the steel wool treatment too. (Btw, how's the blue '48 Continental?)

Tinker, thanks for the pictures and the details. It really brought out the white!

I made a deal for a '49 Schwinn straight bar today that supposedly has spent the last 40 years in a hay loft. It's filthy but even with all the grime, it looks like most of the paint will come to life without soaking. We'll see when it gets here.


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## SirMike1983 (Sep 18, 2016)

mbstude said:


> Thanks for the replies, guys. I'm a big fan of Evaporust and I'll use that on small parts, but I'm wanting a more cost effective way to soak larger parts, like bike rims or whole frames if it comes down to it. After a few hours of reading tonight, I ordered a bag of citric acid and will give that a try. The toxicity of the oxalic acid scares me a bit. There's a lot of rusty junk around the shop so it'll be fun to experiment.
> 
> Mike, I came across your blog post while searching older threads on here. A very good read! I like the steel wool treatment too. (Btw, how's the blue '48 Continental?)
> 
> ...




If it's all like that, I would not do a large-scale soak. The thing about soaking a whole frame or the like is that you either (a) cannot allow the solution into the tubes, or (b) have to have a way to neutralize the acid in the tubes, then blow out any residual moisture. I'd save a big soak of a whole frame for a worse condition bike.

What may work is a "bandage" set. You soak rags in your acid solution and wrap the tubes in the wet bandages for a certain time. It's a bit less aggressive, so it may work slower.The bandages also allow you to focus on one or two areas at a time. 

If it were me, I'd start with a WD40 treatment using 0000 steel wool and a light touch, and see where it goes. You might not even need to use the solution on that.


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## the tinker (Sep 18, 2016)

A word of caution about soaking stuff in Oxalic acid. I am posting this because I have done this with lousy results. I tried the bandage soak. Also the partial soak of only part of an object.  { wheels....frame.....fenders }
Submerge the whole frame or fender, wheel whatever or not at all. . If not you will end up with a splotchy looking frame doing the soaked rag thing. Build something the shape of your frame or whatever and line with plastic sheathing to completely submerge your item.When done  the Oxalic Acid will be gone after a good washing. It will not continue to "eat" away at the inside of your bike frame. It is not like submerging or applying  Muriatic acid to your parts. Granted Oxalic Acid is a toxic chemical and an acid but is more on a par with citric acid [your lime juice]  then a something like Muriatic..
It is tempting on a large object like a rim or fender to soak only half of it at a time because of lack of a large enough container. What happens be it because of water temperature,chemical strength , exact matching soak times and the overlap of soaked areas..... or.a combination of all, you will see a difference between the two soaked areas. Gotta soak the whole thing . Sometimes One hour using  hot water is enough I have done frames in three hours. Something really badly rusted like those Huffman fenders posted earlier took an overnight bath.
By trying to do half an item at a time there will be a dirty looking "Line" in the paint between the two soaks.  And it don't come out.


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## GTs58 (Sep 18, 2016)

the tinker said:


> A word of caution about soaking stuff in Oxalic acid. I am posting this because I have done this with lousy results. I tried the bandage soak. Also the partial soak of only part of an object.  { wheels....frame.....fenders }
> Submerge the whole frame or fender, wheel whatever or not at all. . If not you will end up with a splotchy looking frame doing the soaked rag thing. Build something the shape of your frame or whatever and line with plastic sheathing to completely submerge your item.When done  the Oxalic Acid will be gone after a good washing. It will not continue to "eat" away at the inside of your bike frame. It is not like submerging or applying  Muriatic acid to your parts. Granted Oxalic Acid is a toxic chemical and an acid but is more on a par with citric acid [your lime juice]  then a something like Muriatic..
> It is tempting on a large object like a rim or fender to soak only half of it at a time because of lack of a large enough container. What happens be it because of water temperature,chemical strength , exact matching soak times and the overlap of soaked areas..... or.a combination of all, you will see a difference between the two soaked areas. Gotta soak the whole thing . Sometimes One hour using  hot water is enough I have done frames in three hours. Something really badly rusted like those Huffman fenders posted earlier took an overnight bath.
> By trying to do half an item at a time there will be a dirty looking "Line" in the paint between the two soaks.  And it don't come out.




That's some good advice Tinker. From my experience, I'd like to add that the amount of rust and the *OA/water ratio* have a lot to do with the time you soak. I prefer a stronger mix and less time in the tub. I've also noticed that the solution loses it's potency as the hours roll by so depending on your mix it may be pointless to leave the items in the tub for long periods of time. The old paint is porous so I'm against leaving painted objects in the tub for long soaks that could cause future rusting under the good paint. If you look at an old Schwinn that has the candy colors you can see the cancer underneath the color coat but it's not yet at the surface of the paint. It looks like someone sprayed the candy coat over rusted areas. You can't see this rusting process underneath a solid color paint but I'm sure it's no different than the candy colors.


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## vincev (Sep 18, 2016)

I use 1 tablespoon per gallon.Soak time 8 hours Tinker is right.Dont partially soak a large piece.Get a cheap kids plastic swimming pool at Walmart and submerge frame fenders ,etc.all at once.


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## the tinker (Sep 19, 2016)

vincev said:


> I use 1 tablespoon per gallon.Soak time 8 hours Tinker is right.Dont partially soak a large piece.Get a cheap kids plastic swimming pool at Walmart and submerge frame fenders ,etc.all at once.



Once again another post is starting it's inevitable slide downhill.  I see Dave Marko and Vincent have joined in. 
This thread is now officially doomed.  Marko will say something like," Yeah, Vince then lets his grandkids swim in the pool."
Then Vince will say something back like ,"Dave uses the spent O.X. solution for his margarita mix, also to soak his feet."

What does it matter anyway? we have beat this oxalic acid thing to death. 



"Look, we are all sick and tired about this Oxalic Acid crap.".


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## vincev (Sep 19, 2016)

,Dave uses the spent O.X. solution for his margarita mix, also to soak his feet.


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## mbstude (Sep 19, 2016)

My apologies for starting the thread.


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## Greg M (Sep 20, 2016)

You're forgiven, just don't let it happen again.
Who am I kidding? It's impossible to stop those two.


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## RustyBSA (Sep 25, 2016)

If I was to clean up chrome bike parts with OA what would you put on if afterward to stop it rusting again?


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## Evans200 (Sep 25, 2016)

RustyBSA said:


> If I was to clean up chrome bike parts with OA what would you put on if afterward to stop it rusting again?



Use some chrome polish, and keep the bike out of the elements.


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## Eric Amlie (Sep 27, 2016)

I wax the chrome after derusting to help seal it.


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## RustyBSA (Oct 2, 2016)

Ok so I used OA on a chrome rod actuated braking system. I was very impressed with the amount of rust it got rid of. But under the rust the metal is very pitted and dull. What's the next step, would you polish it up on a buffer wheel, if so what type and which compound would you use. I'm up for the hard work but not willing to pay to get it re-chromed.


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## RustyBSA (Oct 6, 2016)

Ok so I cleaned up my brake lever using OA then on a wire wheel, it come out dull and very pitted. I want to polish it up as best I can and just accept it as rustic looking, what is the best process and compounds to use to get it a shiny as possible and also stop it rusting in the future.


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## pelletman (Oct 12, 2016)

I like WaxOyl, and I also like 10:1 water to molasses mixture (from tractor supply) to derust stuff


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## pedal_junky (Oct 15, 2016)

OA worked good on this one. Used about 2 cups when I did the frame and tank together in warm water for 4 hours. No oil or boiled linseed was used after.


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