Classic & Vintage - Help with Oxalic Acid Use
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11-15-10, 08:52 AM
Ok, I've managed to work on vintage bikes for several years without using Oxalic Acid. I've finally decided to take the collective advice here and start using it. But I have some questions.
1. The bottle I bought says it's concentrated and I should cut it by a factor of 4. Do you use it straight or cut?
2. How long is safe to leave chrome parts and/or non-chrome parts in the bath?
3. What happens if you put rubber in the acid bath? I have a chrome MTB seat post clamp that needs a bath bad, but it has a rubber tip that can not be removed. I don't want to ruin the rubber tip.
Thanks for any help.
11-15-10, 09:24 AM
What kind of OA did you buy? When I use wood/deck bleach, I heavily dilute (approx. 1 tablespoon of deck crystals into a gallon or two of water) and then soak items in the bucket overnight. If you want a mild solution, try Barkeeper's Friend. I mix it with a very small amount of water to make a paste. Use sponge applicator to rub on, leave for a minute or two, rinse off.
Sorry, I have no idea about the rubber.
And, in case people arent' aware, OA can alter paint.
11-15-10, 09:36 AM
I've been using it for the past month in a very strong solution: 1/4 cup of the powder to a gallon of water. It's been working wonderfully. Usual soak is 24 hours, I've had stuff forgotten for days in it with no problem.
11-15-10, 09:44 AM
I couldn't find oxalic locally but my hardware store had something on the shelf for removing rust and rust stains in a spray bottle and the active ingredient is Phosphoric acid.
I decided to try it, I don't have any set mixture but I used a couple gallons of water in a plastic tub and added a few ounces of the product and it's been working extremely well.
Eats the rust and leaves no residue, I accidentally put in one of those old perforated headset washers off a Peugeot in there and it started to foam like an alka seltzer almost immediately so I yanked it out and rinsed it quickly.
I was using Naval jelly but it's a lot more time consuming and you really have to watch it.
11-15-10, 10:15 AM
Curious why people prefer Oxalic acid over Naval Jelly? (Naval Jelly, btw, has phosphoric acid as its active ingredient.)
I believe i've read that Oxalic Acid is not as diluted as Naval Jelly (I have no personal experience with either)
11-15-10, 03:50 PM
Thanks for the comments. I can see as far as the dilution, I'll have to do trials to see whats best, the same with the amount of time in the bath. My first few tries have been pretty good. It sure beats trying to clean up a piece with Brillo.
#1. Take back the bottle stuff, it is expensive water (very dilute). The stuff in a bottle is a huge ripoff. Instead, go to Sherwin Williams paint store and buy the pure oxalic: 12 ounces will cost you about $9. FWIW: I buy it five pounds at a time from Van Dykes (mail order) for about $12 as I recall. But you don't need that kind of quantity. Stop by Waynesville and I will give you some.
2. How long is all about concentration. I use the solution really dilute (so it takes longer to work, but costs less and is easier to handle: a concentration by weight of about 0.2% to 0.4%). At that strength, I let it sit for about 24 hours. And then I keep reusing the solution, several times, til I need the room and then I dump it. My current bath has treated at least ten frames.
3. Most rubber is pretty acid resistant. I would probably test something first, or just treat it briefly. Recognize that there are a lot of different materials that people call "rubber", it is not all the same for sure.
4. Why not naval jelly? Try soaking the inside of a frame, an entire frame or fork in naval jelly. I don't see a way it would work. Oxalic is cheap and effective. Why use something more costly and less effective? For small spot treatment, use the weapon of your choice: naval jelly or whatever.
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