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  1. #1
    Senior Member Tormoza's Avatar
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    Somthing rolling around in the top tube ...

    Hope this an appropriate forum for my question. I recently bought on eBay a very nice frame made of Reynolds 653 tubing. Problem: something (probably a small piece of metal) is loose and rolling around in the top tube.

    The joints between the top tube and the headset, and with the seatpost are entirely sealed: that is, there's no opening that would allow me to shake out this piece of metal.

    So, my question is, what can I do about this? What might be safe and what might damage the frame's integrity?

    TIA, Paul

  2. #2
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    There should be air release holes in the seat and head tubes, as large as 1/4". Air expands and will destroy the weld or braze unless there is an air escape. Look for these, they should be centered on the top tube butts inside the head and seat tubes. You might be able to magnet the specs out those holes, or use compressed air, or you might be able to get a drop of epoxy in there to bind the fragment. In theory you could drill a small 1/16" hole on the centerline underside within the butts of the top tube, and get the chip to that point and inject some epoxy to control it there. Simpler, if the chip is magnetic would be to get a rare earth magnet and see if placing the magnet on the tube somewhere would stop the rattlings. Presumably you would have to leave the magnet there permanently, but it is only the size of a breath mint and shouldn't be a big deal.

  3. #3
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    Other options: If there is no accessible vent hole you can drill one with a long bit going through the seatpost slot, then try to get the piece of whatever out. If it doesn't come out you can bind it w/glue like Peterpan said or shoot some Framesaver in there and it will "goop" in place.
    Or do what I would do, build up the bike and forget about it- I'll bet you never hear it when you're riding.

  4. #4
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    Oops! Double post.
    Last edited by Live Wire; 04-10-08 at 07:47 PM.

  5. #5
    Senior Member Tormoza's Avatar
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    Thanks for the tips -- I was thinking along the lines of drilling a small hole and squirting in some silicone sealer. Epoxy sounds like the way to go. I'll double check to see if there are any holes there already, but I looked pretty closely and didn't see anything.

    I might get used to the sound, but I have a friend I sometimes ride with ... one time I had a squeak from either my bottom bracked or a cleat. He kept looking over at my bike ... finally suggested "we could fix that if it bothers you." No, I answered, doesn't bother me. But he spent the next half hour continually throwing glances at the source of the squeak. Obviously it bothered HIM, which finally bothered ME, so finally we stopped and took care of it.

    Long story short: if it doesn't bother me, it's going to bother someone

  6. #6
    Senior Member Nessism's Avatar
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    There has to be vent holes unless someone sealed them over. Might be tricky but you could always drill your own hole and shake the metal out.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

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  7. #7
    Space Dust
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    Why would there HAVE to be vent holes? Temperature changes would need to be huge to make any significant pressure changes. The pressure changes would also need to be huge to make any significant strength changes.

  8. #8
    Senior Member Nessism's Avatar
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    Quote Originally Posted by Torque1st View Post
    Why would there HAVE to be vent holes? Temperature changes would need to be huge to make any significant pressure changes. The pressure changes would also need to be huge to make any significant strength changes.
    During manufacturing of the frame a vent is needed since the air heats up from the welding/brazing process.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

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    I have seen and done a lot of welding and brazing without vent holes and there were no air pressure problems.

    This "vent hole air pressure thing" is probably some frame builders line of BS about why his frames were superior...

  10. #10
    Decrepit Member Scooper's Avatar
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    I'm not a framebuilder, but have read extensively on the subject and my understanding is that when a lugged joint is prepared with flux and is heated to 800 F to 1100 F to introduce silver solder, without vent holes to allow exanding air trapped in the tube to escape, pressure from the trapped heated air and gasses can and does interfere with the smooth flow of the solder as the builder uses heat to draw the solder into the joint. Providing a vent during the brazing process allows expanding air or gases to escape as the molten filler metal flows into the joint. Venting the assembly also prevents entrapment of flux in the joint. Venting to avoiding entrapped gases or flux reduces the potential for voids in the joint. Flux is designed to be displaced by molten filler metal entering a joint, and vent holes allow this displacement to take place without the pressure of heated air and gasses impeding it.
    - Stan

  11. #11
    Space Dust
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    Normally the joint itself is cooling as the silver is drawn in but since you have read extensively the explanation sounds good enuf to me on silver brazing, -thanks!

  12. #12
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    Silver is drawn to the heat, lead on a plumbing joint, etc... The torch remains in play to direct the silver wherever it needs to go.

    The vent issue isn't only relevant to lugs, it affects brazed and welded joints also. It can displace molten materials, or introduce contamination.

    One end of the tube can be welded in place with the other open, depending on assembly practices. But if the whole mess is fixed in a jig a number of sections will not be free becoause the butts have already been closed, and others may be closed because of the way the jig holds the tubes. Or there can be backpurging going on.

    If you do decide to drill some holes and can't get a bit working fromt he inside, be sure to choose locations in the butts and out of the main load paths. inside the main triangle for instance, not on the outside surfaces. Choose an area on the TT you don't think will get wet, and you are probably on the right track.

  13. #13
    Space Dust
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    A Dremel tool with a burr may work if it will reach. You don't need a huge hole to drop in some epoxy.

  14. #14
    Eternal n00b
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    Quote Originally Posted by Tormoza View Post
    So, my question is, what can I do about this? What might be safe and what might damage the frame's integrity?

    TIA, Paul
    Simple, cut the TT and DT and install couplers so you can transport the bike easier, bonus is when you cut the TT you can remove said piece of whatever...

    Giant OCR3 w/ Ultegra, D/A, Chris King- Commuter/Road bike
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  15. #15
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    Quote Originally Posted by Torque1st View Post
    I have seen and done a lot of welding and brazing without vent holes and there were no air pressure problems.

    This "vent hole air pressure thing" is probably some frame builders line of BS about why his frames were superior...
    More important than the whole "vent hole air pressure thing" thing is soaking the flux out. That's boric acid, which would love to etch away and weaken the frame if given the time. No vent holes=no way for water to get to all the fluxed surfaces.

  16. #16
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    Thanks, Excellent information!

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