oxalic acid - finer points
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curmudgineer
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oxalic acid - finer points
I've read many threads over the past 2 years discussing oxalic acid and other rust removal methods.
I'm undertaking a full frame restoration and and seeking some finer points on oxalic acid, that I don't recall being discussed in the threads I've read.
If I missed something, please post a link. I asked at my local hardware store, and they didn't have oxalic acid, as such.
They had a 1gal. jug of deck cleaner/brightener, containing oxalic acid, in undisclosed concentration. The directions on the container state to use undiluted.
I'm intending to immerse my frame in my bathtub containing oxalic acid solution.
I estimate the volume is 1000-1500L.
Questions I have are:
I'm undertaking a full frame restoration and and seeking some finer points on oxalic acid, that I don't recall being discussed in the threads I've read.
If I missed something, please post a link. I asked at my local hardware store, and they didn't have oxalic acid, as such.
They had a 1gal. jug of deck cleaner/brightener, containing oxalic acid, in undisclosed concentration. The directions on the container state to use undiluted.
I'm intending to immerse my frame in my bathtub containing oxalic acid solution.
I estimate the volume is 1000-1500L.
Questions I have are:
- Is there a recommended dilution ratio for the type of deck cleaner/brightener that my hardware store carries?
- Are there any recommended vendors to try, in Southern Ontario, for pure oxalic acid, or concentrated solution?
- Any other suggestions for significant surface rust removal, prior to repaint?
In addition to the usual scratches and chips, there are large areas of missing paint, where the steel has surface rust.
The fork and stays are half-chromed (with only superficial rust pits), so I don't want to sandblast the whole frame.
#2
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I have used a half cup of the oxalic acid in 10 gallons of water with good results.
In earlier threads, I think somebody said 3% solution was sufficient. 3 grams per liter or one half ounce per gallon would be close enough. (28 grams per ounce - ~4 liters in a gallon)
In earlier threads, I think somebody said 3% solution was sufficient. 3 grams per liter or one half ounce per gallon would be close enough. (28 grams per ounce - ~4 liters in a gallon)
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Sometimes it is in powder form labeled as wood bleach or brightener.
Much cheaper than the pre mixed stuff.
I looked and looked, found the pre mixed that was very pricey, then asked a fellow who looked like he could answer a real question, Wood Bleach, the ingredient was listed as oxalic acid, and it gave ratios as to concentration on the box.
1000L (1,000 liters) is quite a lot!
Much cheaper than the pre mixed stuff.
I looked and looked, found the pre mixed that was very pricey, then asked a fellow who looked like he could answer a real question, Wood Bleach, the ingredient was listed as oxalic acid, and it gave ratios as to concentration on the box.
1000L (1,000 liters) is quite a lot!
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Try the hardware store, then the Pharmacy - ask they may have it in back or can order or ebay the web or
https://www.amazon.com/Oxalic-Acid-fo.../dp/B001F2US4U
https://www.alphachem.ca/
https://www.amazon.com/Oxalic-Acid-fo.../dp/B001F2US4U
https://www.alphachem.ca/
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Half a cup /10 gals, (or about a tablespoon per gallon) works well enough - A little extra time is preferred to too strong a solution.
(All the babble about "grams" and "liters" has me completely nonplussed! )
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Here in TN it's sold in powdered form at Sherwin-Williams paint stores. I've heard the meth-heads use it to cook up their brew. It may not be available much longer, gone the way of sinus meds!
#10
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Here's a thread from the Schwinn forum with a lot of info: https://www.schwinnbikeforum.com/index.php?topic=2969.0 As far as the bathtub though, I don't think OA is to be disposed of like that. I believe to dispose of it it's to be mixed with soda ash and coverted to a salt. There's a link to the MSDS on the above Schwinn link, but here it is anyway https://fscimage.fishersci.com/msds/17361.htm
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I use a fair amount of it, so I buy mine here, 5 pounds at a time.
https://www.van****staxidermy.com/Sea...=oxalic%20acid
https://www.van****staxidermy.com/Sea...=oxalic%20acid
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I've read many threads over the past 2 years discussing oxalic acid and other rust removal methods.
I'm undertaking a full frame restoration and and seeking some finer points on oxalic acid, that I don't recall being discussed in the threads I've read.
If I missed something, please post a link. I asked at my local hardware store, and they didn't have oxalic acid, as such.
They had a 1gal. jug of deck cleaner/brightener, containing oxalic acid, in undisclosed concentration. The directions on the container state to use undiluted.
I'm intending to immerse my frame in my bathtub containing oxalic acid solution.
I estimate the volume is 1000-1500L.
Questions I have are:
I'm undertaking a full frame restoration and and seeking some finer points on oxalic acid, that I don't recall being discussed in the threads I've read.
If I missed something, please post a link. I asked at my local hardware store, and they didn't have oxalic acid, as such.
They had a 1gal. jug of deck cleaner/brightener, containing oxalic acid, in undisclosed concentration. The directions on the container state to use undiluted.
I'm intending to immerse my frame in my bathtub containing oxalic acid solution.
I estimate the volume is 1000-1500L.
Questions I have are:
- Is there a recommended dilution ratio for the type of deck cleaner/brightener that my hardware store carries?
- Are there any recommended vendors to try, in Southern Ontario, for pure oxalic acid, or concentrated solution?
- Any other suggestions for significant surface rust removal, prior to repaint?
In addition to the usual scratches and chips, there are large areas of missing paint, where the steel has surface rust.
The fork and stays are half-chromed (with only superficial rust pits), so I don't want to sandblast the whole frame.
I would think phosphoric acid would be more effective, but that is also toxic and causes skin burns.
#13
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Disposal isn't a big deal if you don't mix it strong. I fill a 20 gallon rubbermaid large storage tub with about 1/4-cup of Savagran and it is so weak that you can put your bare hands into it and it doesn't even make my skin feel slimy. I've got a big metal hook I use to grab stuff out of it so do avoid putting my hands in it but we are talking an acid that is weaker than even the vinegar you can buy off the grocery shelf. I'm sure to thoroughly rinse my hands or any skin that gets any OA on it well. More water is the best/easiest way to neutralize a weak acid like this. I rinse all parts that come out of the OA bath and gently scrub with a soft non-marring white scrubby pad. This neutralizes the acid and flushes the part clean of any salt residue that is left behind by the reaction.
I use the mix until it is getting yucky and the parts start getting more of a film of white or greenish crap on them (from the salts I suppose) and the bottom of the container has a coat of yucky goop on the bottom. Then I just dump it down the drain out back that goes into the same grease trap that our condo pipes all the kitchen drains into. There is a manhole out back of our small 8-unit building to access the grease trap and it's usually full of bug chunks of kitchen grease/waste that I am the one who cleans out every year or so. When whatever tiny bit of acid I dump down the back drain hits that grease in that trap (8 feet of pipe) it's just going to react and be used up. I usually toss an extra 5-gallon bucket of water down that drain to flush out any residual acid in that 8 feet of pipe so it's not damaged.
I use a large plastic Peanut Butter jar for small parts inside. I might mix that a little bit stronger -but not much. When I'm done with that I'll put some baking soda into it until it stops foaming (doesn't take much) and then dump that too.
You don't need to make the OA very strong. Just a very mild weak solution will do the job if you just let the parts sit a little longer. The stronger the acid the more likely you will damage the finish on parts that were not very well coated like common fasteners that were zinc-coated Those will turn black or a dark grey if you leave them in long. Those parts can be easily damaged even in the ultrasonic parts washer with a little bit of dish detergent if left in through too many cycles.
Another hint for OA is to do a good job of cleaning the parts BEFORE you put them in the bath. Grease and dirt on frames or other parts will merely serve to coat the rust you want gone and protect it from reacting with the acid. You want it GONE before you put the parts into the bath. That grease also reacts with the OA and makes it go bad faster. I scrub everything with a nylon brush and some soapy water to clean it and expose the bare rust from under the grease and grime.
I use the mix until it is getting yucky and the parts start getting more of a film of white or greenish crap on them (from the salts I suppose) and the bottom of the container has a coat of yucky goop on the bottom. Then I just dump it down the drain out back that goes into the same grease trap that our condo pipes all the kitchen drains into. There is a manhole out back of our small 8-unit building to access the grease trap and it's usually full of bug chunks of kitchen grease/waste that I am the one who cleans out every year or so. When whatever tiny bit of acid I dump down the back drain hits that grease in that trap (8 feet of pipe) it's just going to react and be used up. I usually toss an extra 5-gallon bucket of water down that drain to flush out any residual acid in that 8 feet of pipe so it's not damaged.
I use a large plastic Peanut Butter jar for small parts inside. I might mix that a little bit stronger -but not much. When I'm done with that I'll put some baking soda into it until it stops foaming (doesn't take much) and then dump that too.
You don't need to make the OA very strong. Just a very mild weak solution will do the job if you just let the parts sit a little longer. The stronger the acid the more likely you will damage the finish on parts that were not very well coated like common fasteners that were zinc-coated Those will turn black or a dark grey if you leave them in long. Those parts can be easily damaged even in the ultrasonic parts washer with a little bit of dish detergent if left in through too many cycles.
Another hint for OA is to do a good job of cleaning the parts BEFORE you put them in the bath. Grease and dirt on frames or other parts will merely serve to coat the rust you want gone and protect it from reacting with the acid. You want it GONE before you put the parts into the bath. That grease also reacts with the OA and makes it go bad faster. I scrub everything with a nylon brush and some soapy water to clean it and expose the bare rust from under the grease and grime.
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I can't see it being any worse than pouring Drano in your pipes.
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Would Draino hurt your pipes?
oh, yes -it would!
LOL! I never hear that ad any more. I guess they got sued.
I've got a used P-trap I saved somewhere that someone foolishly poured draino down many times and you can see just how it was thinned to the point of nearly being like tin-foil at the bottom before it actually cracked and began leaking.
That Drano stuff is evil -but even though this is the case people can get away with it for a long time/many uses before it is a problem. That first P-trap under the drain is the one that gets the most damage usually.
OA is only a tiny fraction of a percent as strong as Draino if it is mixed correctly. If this were not the case it'd eat at the good metal of your frame or other dipped steel parts. OA is special because even at a very dilute solution it still LOVES rust. OA bonds with and dissolves the rust away and pretty much ignores the good metal. It's special stuff.
It can't fix deep pitting or do much to take away that "hard black rust" that is like parkerizing but the brown rust is simply washed away magically.
Don't even think of putting aluminum "alloy" parts into the OA. It's not a good idea. It's just for steel.
oh, yes -it would!
LOL! I never hear that ad any more. I guess they got sued.
I've got a used P-trap I saved somewhere that someone foolishly poured draino down many times and you can see just how it was thinned to the point of nearly being like tin-foil at the bottom before it actually cracked and began leaking.
That Drano stuff is evil -but even though this is the case people can get away with it for a long time/many uses before it is a problem. That first P-trap under the drain is the one that gets the most damage usually.
OA is only a tiny fraction of a percent as strong as Draino if it is mixed correctly. If this were not the case it'd eat at the good metal of your frame or other dipped steel parts. OA is special because even at a very dilute solution it still LOVES rust. OA bonds with and dissolves the rust away and pretty much ignores the good metal. It's special stuff.
It can't fix deep pitting or do much to take away that "hard black rust" that is like parkerizing but the brown rust is simply washed away magically.
Don't even think of putting aluminum "alloy" parts into the OA. It's not a good idea. It's just for steel.
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I used to dip entire frames in a week bath of OA to treat rust until I got a tip from Khatful. On frames with minimal and typical rust around the lugs and spot paint nicks, I use a small amount of crystallized wood bleach mixed with a little water to form a slurry paste, then tooth brush it onto cleaned rusty areas. Then leave it overnight. It has worked for me fairly well. I emphasize that the rusty areas need to be cleaned because, in my experience, even a minimal glaze of grease will keep the OA from penetrating the oxidized metal.
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Oxalic acid doesn't hurt or burn your skin, but each exposure goes a bit to your kidneys and doesn't wash out, so you are poisoning yourself, painlessly. Still it seems better than sulfuric acid. Use proper precautions.
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Re: Disposal, as I was purchasing some West Marine branded Oxalic Acid about 20 yards from Newport Bay, I asked the guy at the store about disposal. He just kind of gave me a funny look for a second and then started to laugh. He said "You know, I never thought about it that way, but I'm pretty sure that 90% of the guys that buy this stuff put it right on the deck and then hose it right off into the water."
We talked for a bit and agreed that if it were that detrimental to the environment, there would be no way they could package, sell, and use it in the manner which they do.
We talked for a bit and agreed that if it were that detrimental to the environment, there would be no way they could package, sell, and use it in the manner which they do.
#19
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Re: Disposal, as I was purchasing some West Marine branded Oxalic Acid about 20 yards from Newport Bay, I asked the guy at the store about disposal. He just kind of gave me a funny look for a second and then started to laugh. He said "You know, I never thought about it that way, but I'm pretty sure that 90% of the guys that buy this stuff put it right on the deck and then hose it right off into the water."
We talked for a bit and agreed that if it were that detrimental to the environment, there would be no way they could package, sell, and use it in the manner which they do.
We talked for a bit and agreed that if it were that detrimental to the environment, there would be no way they could package, sell, and use it in the manner which they do.
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If you get bit of the powder or raw flakes in your eye you are going to be in a WORLD of hurt.
I use a disposable plastic spoon to dispense the stuff and throw it away each time making sure it goes directly into the garbage so nobody would ever use it again. I'm very careful to wash up and rinse very well anything that may have been contaminated by the flakes. In this form it is a pretty strong acid and until it is diluted is quiet dangerous. Getting some on your hands and then later touching your face or eyes could be very bad.
Adding water to it dilutes it and then it really isn't very bad at all. The more water the more diluted it is -by definition.
The advice above about making a slurry and using a toothbrush gives me the willies. The thought of that strong acid being flung everywhere by the bristles doesn't sound safe at all. At the very least it sounds like a recipe to ruin your work clothes with tiny little holes when it comes out of the washing machine where the acid dripped and dried, eating the fibers. At the worst it could spritz into an eye -causing burning to the delicate eye membranes. I have only two eyes and the one is not a spare...
I use a disposable plastic spoon to dispense the stuff and throw it away each time making sure it goes directly into the garbage so nobody would ever use it again. I'm very careful to wash up and rinse very well anything that may have been contaminated by the flakes. In this form it is a pretty strong acid and until it is diluted is quiet dangerous. Getting some on your hands and then later touching your face or eyes could be very bad.
Adding water to it dilutes it and then it really isn't very bad at all. The more water the more diluted it is -by definition.
The advice above about making a slurry and using a toothbrush gives me the willies. The thought of that strong acid being flung everywhere by the bristles doesn't sound safe at all. At the very least it sounds like a recipe to ruin your work clothes with tiny little holes when it comes out of the washing machine where the acid dripped and dried, eating the fibers. At the worst it could spritz into an eye -causing burning to the delicate eye membranes. I have only two eyes and the one is not a spare...
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- Any other suggestions for significant surface rust removal, prior to repaint?
In addition to the usual scratches and chips, there are large areas of missing paint, where the steel has surface rust.
The fork and stays are half-chromed (with only superficial rust pits), so I don't want to sandblast the whole frame.
Soak old tee shirts in Evaporust. Wrap rags around frame. Wrap rags with cling wrap to prevent evaporation of the Evaporust.
Evaporust is non-toxic.
#23
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Thank's for all the educational input, C&V'uns. OLDYELLER, thanks for the input. I have a mail drop across the line, so I ordered online from one of the previous tipped vendors.
iab, Evaporust is a great tip, and it's locally available & cheap. I'll give it a try before the oxalic acid. I may have 5lb oxalic acid up for grabs.
iab, Evaporust is a great tip, and it's locally available & cheap. I'll give it a try before the oxalic acid. I may have 5lb oxalic acid up for grabs.
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I just bought a gallon jug of deck cleaner at Lowes. Can't remember what the concentration was. I covered the bike box that the frame came in with plastic and dumped the jug in. Filled the rest with water and put the Frame and fork in. It took a couple of days to completely remove the rust. I didn't worry about the precise measurement because I checked the frame two or three times a day. I could tell if it was too strong and if so, I would have diluted the mixture. Oxalic acid is pretty mild. All the concentration does is determine the amount of time you have to soak the parts.
Edit...The concentration in the jug of deck cleaner was pretty mild.
Edit...The concentration in the jug of deck cleaner was pretty mild.
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#25
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The second time I did an OA soak the kiddie pool I was using leaked out into the basement (!) Luckily nothing was ruined and I cleaned it up fairly quickly, but be careful of that. In fact, probably best to do it outside.