how do i stop sandpaper from loading up ?

Discussion in 'Fiberglass and Composite Boat Building' started by lobsterman, Aug 31, 2011.

  1. lobsterman
    Joined: Mar 2004
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    lobsterman Junior Member

    When sanding fiberglass, how do i stop sandpaper from loading up with resin spots ?, (they wind up coming off the sandpaper and then sticking to the resin ). I used the correct ratio's and the resin has cured and set up for over 48 hours but the sandpaper is still loading up.

    I was wondering if someone may have a trick to prevent this from happening soo much ???, such as spreading on some cabosil or wood flour on the surfaces first or ???. Or does someone have an idea for unclogging the sheets (smacking them on a hard surface works for clearing wood dust but not the resin spots).

    P.S. Good sandpaper is not cheap !!!, and cheap sandpaper is not good !!!.
     
  2. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    You need better dust removal with a vacuum.. Best in this regard is Abranet.
     
  3. keysdisease
    Joined: Mar 2006
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    keysdisease Senior Member

    What are you sanding? If its in a mold for a mechanical bond a little die grinder at hi speed with a 16 or 24 disc works fast and won't load up.

    If it's going to get painted anyway a coat of epoxy primer (545 or like) will stop the paper from loading and provide a fairing guide.

    Steve
     
  4. CatBuilder

    CatBuilder Previous Member

    What keys says. Use a low grit number. I find 36 to be good all around for epoxy work. Only other thought is maybe you used slower hardener than your climate dictates and it's still green.
     
  5. Northman
    Joined: Mar 2007
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    Northman Junior Member

    I have never worked with polyester, but if you are talking epoxy I also had problems with regular orbital sanders and the like. Now I use a small Fein multi master (http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=181M74JZBBXCWZ3HSECC). Works much better! I use 40 and 60 grid.
    Don't let it sit to long at a time! Lift it often and let it cool down. When epoxy heats up through friction it will clogg the paper in no time!
    Walter
     
  6. lobsterman
    Joined: Mar 2004
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    lobsterman Junior Member

    Thanks, I am hand sanding with 60 grit between coats or layers on a 12' lumber yard skiff. I guess i can't do the sanding on a warm sunny day. the paper doesn't seem to load up as bad doing it in the cooler evening temps (before the condensation of the night kicks in).
     
  7. Chase_B
    Joined: Aug 2011
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    Chase_B Junior Member

    Take a bar of soap to the sand paper first repeat as needed ! Try to keep the heat down if using power sander. Apply minimal even pressure , do not tip the sander if you can help it , this method also works on hard disc grinders for aluminum , wax will work too if you don't want to use bar soap, difference is the cleaning after sanding is done, water for soap acrylic reducer for wax, do not use Laquer thinner,
     
  8. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    If you didn't use waxed resin, you might not need to sand between layers. To get lumps and things leveled out, you can use a sharp paint scraper instead of paper. It's easy to clean and you can keep re-sharpening it.
     
  9. tunnels

    tunnels Previous Member

    you hit the nail on the head !!unwaxed resin will clog up any paper you can simply soak the paper in a shallow steel dick with a half a litre of acetone , as each sand paper clogs plce it in the acetone for a few minutes the resin simply falls off !!! can re use it over and over many times just keep the acetone covered so it wont evaporate so fast .
    When you work in countries that have little you learn to make do with what you got and make it last as long as possible and a bit more !!:eek:
     
  10. lobsterman
    Joined: Mar 2004
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    lobsterman Junior Member

    I would think the acetone would destroy the sandpaper ???. I actually rarely use acetone, as i use disposable paper chowder pots and cheap rollers + brushes. I only seem to use it when i use a bubble roller, or to wipe down sanded filler before glassing.
     
  11. tunnels

    tunnels Previous Member

    I have used this system of washing with acetone since 1984 and has never failed once ever since i first worked inTahiti . When i went to Australia i show the guys how to do it same when i went back to nz we used it not only for sanding glass but also fillers that also fill paper at times . Wet and dry sand paper ordinary sand paper even grinding discs . we used to wash discs till they were so worn out there was no grit left to grind with .
    Why dont you try it!! it works !!!:p
     
  12. latman
    Joined: Mar 2010
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    latman Junior Member

    Epoxy sands easier after postcure.
     
  13. m3mm0s rib
    Joined: Aug 2011
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    m3mm0s rib Senior Member

    Grate the epoxy with a sharp tool. Do not rub
     
  14. Flying Flivver
    Joined: Oct 2011
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    Flying Flivver Junior Member

    I'm a cabinetmaker and we use a rubber block called a crape block you hold it to the abrasive as it is moving to clean it, your sandpaper will last much longer. you can find them at most wood working shops.

    use high quality open grained paper with a film backing and good dust collection.

    The grit in sand paper is bonded with a resin make coat so soaking it in acetone will only make the grit fall off.
     

  15. LP
    Joined: Jul 2005
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    LP Flying Boatman

    Often times I will use a waterproof sandpaper and wet sand with a spray bottle. Of course, this limits your ability to use eletricity. I just purchased some 60 grit 3M proffesional grade paper that is waterproof though it is not marketed as such.
     
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