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  1. #1
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    Oxalic acid treatment on inside of frame

    My beautiful reparto corse frame has developed light rust in the frame. It isn't severe, but I figure if it's a little bit, it won't be a pain in the butt to go ahead and take care of it and prevent a big problem (Uh, lake effect, anyone?). I'm building it up with brand new ultegra everything... and I plan on treating the inside with framesaver before I assemble. I read that it was necessary to remove the visible rust with an oxalic acid treatment. The outside of this columbus tsx frame is chromed. I Do NOT want to damage decals, paint, etc. Note: I do have internal cable routing.


    I've read the forums about oxalic acid-- it seems the way to go cause it's safe on paint and it doesn't leave bad products on the frame. If I were to go this route, what concentration should be used to have an equally effective and safe treatment?

    I need to submerge the entire frame to do this, right? Is there are work around (like flushing it out)? I figure the answer to this question is no--- because it needs to sit for a while.

    What (if needed) should I use to clean the dirt and grime from the inside before I do anything?

    Thanks!

  2. #2
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    Some stuff to think about:

    do not believe that all the original flux is out. Don't know what the chemistry would be.

    Same goes for any chrome residue hiding, flushing does not always happen as it should between baths.

    Where are the chemistry majors when you need them?

  3. #3
    . bbattle's Avatar
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    oxalic acid acts like a chelator to remove the rust. I wouldn't worry about any flux; it will have oxidized long ago.


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    Two carboxyl gruops put together is oxalic acid? Cool.

    So given that this frame is 13 years old.... the flux would have oxidized long ago?

    So sometimes during manufacturing a little bit of chrome can end up on the inside? Why would this matter for me if oxalic has no effect on chrome?
    Last edited by hillzofvalp; 09-20-08 at 03:59 PM.

  5. #5
    My bikes became Vintage OLDYELLR's Avatar
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    In my opinion, introducing an acid solution to the inside of the frame will only result in corrosion in the long term. You would have to thoroughly rinse it out and then dry every nook and cranny before using the framesaver. And for what? So that you know in your heart there is no surface rust inside while you ride? And what about inside the tubes you can't see? You won't even know if you removed the rust or the moisture afterwards. I would just do the framesaver because it will prevent any rust from growing.
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    That's one way of looking at it, and I do value your opinion. however, it would be nice to not shove brand new components up against rust, ya know? That's what I don't really like. It'd be nice to keep the bike nice so that if I ever need to upgrade, I can advertise the bike as clean and get closer to what I paid for the bike (if I were to get rid of it). If I end up riding for the long-term and this build turns out to be really nice, then I would like to extend the life of the bike.

    Any more opinions? solutions?

    Also, doesn't framesaver work significantly better when there's no rust on the surface of application?

    What do you mean, oldyeller, by "introducing an acid solution to the inside of the frame will only result in corrosion in the long term". Can you further explain this?
    Last edited by hillzofvalp; 09-20-08 at 09:38 PM.

  7. #7
    My bikes became Vintage OLDYELLR's Avatar
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    Quote Originally Posted by hillzofvalp View Post
    it would be nice to not shove brand new components up against rust, ya know?
    You mean shoving a new seat post into a rusty seat tube and screwing a new BB into a rusty shell? Yes, but you could easily clean out the surface rust from the top of the seat tube with oily Scotchbrite wrapped around a dowel and you'd have lots of grease on the seatpost and BB cups.
    Also, doesn't framesaver work significantly better when there's no rust on the surface of application?

    What do you mean, oldyeller, by "introducing an acid solution to the inside of the frame will only result in corrosion in the long term". Can you further explain this?
    The framesaver soaks into surface rust, rendering it inert. Living in the "rust belt" where they salt the roads in the winter to keep idiots who can't drive from running into each other, I have lots if experience with corrosion. I'm junking a car right now because it was driven on salted and gravel roads for the first 10 years of its life and literally fell apart in the 4 years I had it. The top and down tubes and the stays of your frame are connected to the open tubes by little holes. Once moisture gets in there from the oxalic acid treatment, you'll never get it out and they'll rust out from the inside. The acid will remove rust, but unless you can completely rinse it away and protect the steel, the rust will return and keep growing if there is moisture and oxygen available.
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  8. #8
    don't try this at home. rm -rf's Avatar
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    I used oxalic acid on an old Raleigh I rescued from the trash. It worked great on the rust spots on the chrome and paint. I only treated the back stays and the fork, not the main triangle.

    I've seen recommendations to neutralize the oxalic acid with baking soda, but I just rinsed the fork and rear stays by dipping them back in plain water, until the interior filled up, and lifting them out to drain out the weep holes. I probably did this 10 times or so.

    Perhaps some of the experts can explain if this is enough, or what the neutralization does that plain water rinsing doesn't do. Wouldn't you then have to carefully rinse out the baking soda solution anyway?

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    Did you dry it? I mean.. idk. It seem slike it's necessary to dry it by hand. Maybe a blow dryer's air can be routed through a peace of pipe into the frame?


    Idk about neutralization. Can someone shed some light?
    Last edited by hillzofvalp; 09-21-08 at 02:56 PM.

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    You might want to read this thread from another forum.

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    Quote Originally Posted by hillzofvalp View Post
    Did you dry it? I mean.. idk. It seem slike it's necessary to dry it by hand. Maybe a blow dryer's air can be routed through a peace of pipe into the frame?
    Nothing so tough. Seal all the holes except two with pieces of rubber - pieces of an old inner tube will do. Then connect a tank of dry nitrogen to one of the holes with a hose, and crack open the valve. 2-3 psi will do fine. Let it blow through the frame, venting out the other hole (and any weld holes there are) for 30 minutes. Borrow a tank from a friend - the refill is like $15. We use nitrogen to dry out refrigerant lines all day long - it's cheap, non-toxic, and leaves no residue.

  12. #12
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    Ok I raised the question there, too.

    That's a good idea, bikemeister, but does it get rid of ALL the moisture?

  13. #13
    DRF aka Thrifty Bill wrk101's Avatar
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    Submerge it for about a day. Then soak it in a baking soda bath to neutralize. Dry it with compressed air, then treat it with frame saver.

    Take a flashlight and look down the seat tube, towards the bottom bracket. Thats often the first place for internal rust to show up, and is pretty easy to see. Here is a before and after on my 92 Trek 950.
    Attached Images Attached Images

  14. #14
    Senior Member Iowegian's Avatar
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    Quote Originally Posted by wrk101 View Post
    Submerge it for about a day. Then soak it in a baking soda bath to neutralize. Dry it with compressed air, then treat it with frame saver.
    That's what I'd do, too. Use a weak acid solution and just keep it in until it looks good. The soda bath should only take a few seconds. I think the key is to neutralize, dry and treat with frame saver as fast as possible, preferably on a day with low humidity. After that don't worry about it. The inside has been bare steel for how many years and it's still fine. After this treatment, it will last longer than you

  15. #15
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    Quote from Ted Carl at this thread:

    "You can really only get what you can from the insides.

    It will generally turn yellow, and a lot of it will wash right out. But there is still going to be some that gets left behind inside there. Especially since circulation is weak inside there during the bath.

    I tend to believe that once you coat it down with rust preventative after it is loosened and turned into the yellow powder, and most of it is washed out, the rust preventative should keep it from being able to re-bond, and is far better than just letting it go as it was.

    On the other hand, rust never sleeps (someone said that once, lol) . So nobody is ever going to totally stop corrosion on the insides of a frame, unless it is stopped at the production of the bicycle during manufacturing. Even if you painted the insides of the tubing right out of the mill, as soon as it got welded, corrosion would have already started in there. Rustproofing a brand new frame would still not keep it pristine inside there. The day it's manufactured, rust has started in there.

    Get as much as you possibly can out of there. Rust proof it as soon as it comes out of the bath. Then quit getting it wet and dirty inside there (even low humidity helps a lot) (feeding the rust). And that is about all you can really do, and that will make it last many, many years longer than it would have otherwise.

    Even if you have something re-plated, the (much stronger) acid they use in the stripping and in the chroming process, will have lots of rust forming on the insides before you even get it home.

    Don't worry about neutralizing it. Rinsing it good, and coating it, will stop any leftover reaction right away.

    Other than cutting a hundred old frames in half, and bisecting all the tubing, and experimenting with it for years and years, and subjecting it to every different rust proofing, and testing all the results, we will truly never know exactly how long the rust proofing lasts, how long it slows it down for, etc.... It's pretty safe to say that getting as much as possible, and coating it right up, is better than leaving it packed solid with rust, and leaving it to it's own devices to run free though.

    Cheers. "

    So no neutralization?

    And thanks for all of your input.. It's good to hear opinions.
    Last edited by hillzofvalp; 09-21-08 at 10:18 PM.

  16. #16
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    Quote Originally Posted by hillzofvalp View Post
    Ok I raised the question there, too.

    That's a good idea, bikemeister, but does it get rid of ALL the moisture?
    Absolutely! It's what we use in the HVAC industry to remove any residual moisture from inside the systems before adding the freon. Moisture in there will react with the freon/oil/electrical insulation and form ACID. Not a good situation. We use dry nitrogen to drive out every last drop of moisture possible. So, it should work just fine for moisture removal inside your frame tubing.
    Last edited by bikemeister; 09-22-08 at 04:45 PM.

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