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  1. #1
    Back to Biking stedanrac's Avatar
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    Prepping a frame for sandblast/powder coat

    (reposted from the Bike Mechanics forum upon recommendations....)


    Hi Folks,

    I have an older Trek Mountain bike frame that I am prepping for powder coating. I've stripped it completely and degreased it pretty well ( the bottom bracket and frame stem).

    My question is to those who have done this before; what sort of masking is necessary? Do I need to block off the tubes? How do you mask them?

    Thanks for any help.

    Steve
    Last edited by stedanrac; 05-19-08 at 03:41 PM. Reason: fix typo

  2. #2
    sch
    sch is offline
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    One comment, don't sandblast with sand, use a less aggressive media. Sand will
    or can remove a noticeable amount of metal if used by ignorati and a tattooed
    frame is not desirable. Your frame probably has enough thickness in the metal
    not to be weakened significantly but some frames are thin enough (submillimeter
    thickness) that sharp sand can be used to cut the frame in half. Your masking
    material has to withstand the powder coat heat treatment, so inquire of the
    powder coater what to use. Cover all bearing and threaded surfaces. Dropouts
    are not bearing surfaces. Seat tube probably is OTOH, as clearances here are
    pretty snug and cleaning out the seat tube would be a PITA.

  3. #3
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    sch is right: you want "bead blasting" not "sand blasting". One shot of sand and your bike will look like Swiss cheese!

    Any decent powder coat shop will take care of plugging the tubes before powder coating. Are you having a fork powder coated? If so, you'll want them to mask the area where the crown race seats. Also plug anything with threads (e.g. disc brake mounts, water bottle bosses, etc). Finally, they should mask areas where the axles seat. My shop did this, claiming that the pressure from clamping the QR skewers would eventually cause the powder to crack. Sounds like a good idea to me!

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