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  1. #1
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    Stripping and clearcoating an aluminum frame

    Hi.

    I recently found a nice aluminum frame in the trash, it's a Vitus French road bike from the 80's with a funky homeade paintjob that's chipped and ugly as hell.

    I would like to take it down to the bare metal and clear-coat it. I am thinking of using a soft wire brush on a drill to take the paint off and just clear-coating it. Will that work? Thanks for the help.

  2. #2
    Senior Member Joshua A.C. New's Avatar
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    Yeah, it'll work. The brush will leave marks, which might be what you want or might not. They'll be directional around anyplace where tubes meet running perpendicular to the tubes, and sort of random everywhere else. You can, of course, go over it with finer and finer sandpapers, scotchbrite pads, or whatever to get the finish you want.

    I use methylene chloride, though I might try MEK next time. It certainly worked after the methylene chloride did its thing, but failed to take the rest of the paint off. I don't know if it will work without the methylene chloride first. I'll have to find myself another frame first —*and honestly, I'm seriously considering paying for beadblasting and powder coat next time. Stripping a frame is a lot of work and, while it's great having something you did yourself, the recoating is challenging. Fortunately, this is an aluminum frame, so it won't be a really big deal if you miss spots, but you'll have to coat very deliberately since you can't see where you've painted. Do lots of fine coats — I think you probably need at least 6 to get any sort of durability.

    Here are a couple of bikes I've made, complete with stripping. If you scroll down, you can see some other things I make, too, but they're not particularly relevant to this discussion.
    Joshua A.C. Newman,
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  3. #3
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    IIRC, the Vitus frames were bonded and a methylene chloride based paint stripper could damage the bonding adhesive leaving you with a collection of paint-free individual tubes. Also the tubing was quite thin walled and a wire brush may do a fair bit of damage too. Be very careful what ever method you choose.

  4. #4
    Senior Member Joshua A.C. New's Avatar
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    Yikes!

    Uh, yeah, obviously, I'm assuming they're welded. I don't know if methylene chloride attacks epoxy or not. You'll have to do your own research on that.

    Google tells me that they were, indeed, bonded. And if the walls are thin, a steel brush might be too tough on it, too.

    Try acetone? It'll take the homebrew paintjob off easily, leaving you with whatever's underneath, which, if it's in OK condition, you might just want to sand lightly and repaint some other color. It won't get you delicious raw aluminum, but it'll get you a good basecoat, and you won't have to worry about damaging anything while you scrub away at hard-to-reach places.
    Joshua A.C. Newman,
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    Thanks man. Nice link too.

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    Non Tribuo Anus Rodentum and off to the next adventure (RIP) Stacey's Avatar
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    Low pressure, soft particle media blasting?

    Anodized would be cool.

  7. #7
    WNG
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    I own a Vitus 979. They came anodized and painted. I believe the main tubes came painted in the white and black frames. The rest came anodized. It's easy to discern as the anodized main tubes reveal the brushed aluminum pattern.

    A steel brush wheel will destroy the frame. Warning you can't use a steel brush, if particles get embedded into the aluminum, over time, rust dots will form. A fine brass bristle will be less harmful, and should be used in only the tightest confines.
    Careful with any chemical method. The Loctite thermal bond may get damaged. Make sure whatever you use doesn't react with it. A chemical method will get you to the factory finish with the least damage should it be anodized.

    This is a unique frame, with very specific ride qualities. Some find them too soft riding.
    But regardless of their performance, they are collector's items. I can't believe someone tossed one in the trash!

  8. #8
    WNG
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    BTW if it's an anodized frame, and you want to take it down to bare metal to clear coat as stated. Try an ammonia soak to strip off the anodization. Then you can sand and polish to shiny bare metal.

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    Yeah, it was funny because I saw this frame outside of a geeked out bike shop in NYC, so I'm just assuming that someone brought it in for a repair and couldn't pay the fee or something. They just didn't have the time of day to fix it up or sell it.

    I'm thinking with what I've read so far either:
    A) Leave it alone and let the ****ty paint job ward off thieves or
    B) Just sand and repaint

    It is going to be a commuter bike, not a hard racer or anything so I don't think frame flex will be an issue. But it is for my girlfriend and she would probably appreciate the asthetic value of some new paint.

    BTW, does your Vitus 979 have a wishbone-shaped steat-stay? This one does. I have no idea what model it is.

  10. #10
    WNG
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    Wishbone-shaped? No. My seat stays are straight.
    You may need to post some pics to ID this frame.
    If it was tossed out by a bike shop, check it carefully for damage. These are next to impossible to repair.
    Only a few people are qualified to repair these frames. So, maybe they found a defect and wrote it off.

  11. #11
    Dr.Deltron
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    Quote Originally Posted by Seanywonton View Post
    B) Just sand and repaint.
    I vote for B! Least likely to cause frame bonding issues.

    And +1 on finding out if it's damaged somehow. A 979 in a bike shops garbage? Then it probably IS.

  12. #12
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    Option C) Sand and repaint it with "[In black paint], This bike is Stolen, This bike is Stolen", plastered all over the frame, contrasted with white. That would be ironic, especially for New York

    I feel sorry for any New York bikers, if someone stole my bike I would go ape ****. And my bikes only worth a couple hundred! I'm rather sentimental

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    Read Dr D's advice very carefully. Bike Shop? Trash? Probably serious damage. You should do a string-line measurement on the frame before do anything else. Oh... and have you made sure you can't pull any of the tubes out of the joins... it may have been dumped because something ain't bonded properly. Have you checked the BB threads, too? They might be knackered.

    In short, do the checks before committing to the strip job.
    Dream. Dare. Do.

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    That is very good advice on checking the frame for damage, so thank you all.
    So far I have checked the joints - no loose ones, and felt all the tubes for dents or bends. They are all fine. I don't know how to check the frame alignment but by eyesight it looks fine, and I put on the back wheel and it sits properly.

    I still need to check the BB threads. I haven't removed the original yet because I don't have those tools, but I think they will be fine because when I picked it up the cranks were still on too, and there was no looseness or tight spots in the BB rotation.

    It's hard to believe for people like us who actually have fun fixing up bikes and don't like to see a cool old frame go in the trash, but some people just can't be bothered.

    While sanding the paint (we are going to sand and repaint, instead of strip to bare metal), I found the original stickers which say "Vitus 787 Aluminum". Any chance this is the model #? It doesn't matter really I guess, but I am curious.

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    Quote Originally Posted by Seanywonton View Post
    That is very good advice on checking the frame for damage, so thank you all.
    So far I have checked the joints - no loose ones, and felt all the tubes for dents or bends. They are all fine. I don't know how to check the frame alignment but by eyesight it looks fine, and I put on the back wheel and it sits properly.

    I still need to check the BB threads. I haven't removed the original yet because I don't have those tools, but I think they will be fine because when I picked it up the cranks were still on too, and there was no looseness or tight spots in the BB rotation.

    It's hard to believe for people like us who actually have fun fixing up bikes and don't like to see a cool old frame go in the trash, but some people just can't be bothered.

    While sanding the paint (we are going to sand and repaint, instead of strip to bare metal), I found the original stickers which say "Vitus 787 Aluminum". Any chance this is the model #? It doesn't matter really I guess, but I am curious.
    Its easy to check frame alignement using a piece of string. Sheldon Brown has a write up about it.
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  16. #16
    WNG
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    Vitus 787 Al would be the type of tubing in its construction.

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    Good news: I checked frame alignment and it's fine, I also drilled out the back brake hole to accept newer brakes, and installed an octalink BB. So everything looks great!

    We're going full steam ahead with the project, but I one question remains: We decided to paint instead of completely stripping. Can I get a good paint job, one that won't chip off easily, simply by sanding? The paint on the bike seems like it's on there good, so if we just make sure to sand out the dings and rough-up all the surfaces,and re-prime, will we be OK? The other option is we could pay to have the frame sandblasted, and still do the home paint-job.

  18. #18
    WNG
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    you are relying on the paintjob previously to be good enough to adhere the primer to.
    Test its chip resistance. If it's good, then they may have took the steps to paint the frame well.
    Sand all surfaces so that the primer will hold well. You should get a decent finish.
    Don't forget to post pics of the bike!

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