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  1. #1

    Default Thru-Hull Drilling - Bit to use?

    I need to know what type of drill bit to use to drill a 1' hole for a Thru-Hull Intake for an additional ballast pump.I am concerned about chipping the finish. I would assume you would drill it from the outside. I am looking at the WakeMAKERS.com Complete Impeller Pump Ballast Kit.
    07 LSV

  2. #2
    Join Date
    Sep 2010
    Location
    Lake wallenpaupack PA
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    846

    Default

    Quote Originally Posted by Jeffro View Post
    I need to know what type of drill bit to use to drill a 1' hole for a Thru-Hull Intake for an additional ballast pump.I am concerned about chipping the finish. I would assume you would drill it from the outside. I am looking at the WakeMAKERS.com Complete Impeller Pump Ballast Kit.
    Any wood holesaw will work.... tape the outside and drill in reverse( i do the whole hole in reverse)... i would start on the outside then switch to inside and drill about an eighth inch then go back to the outside and. Finish the whole.... this way the inside will not split/splinter when u push thru.....

  3. #3
    Join Date
    Sep 2010
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    Lake wallenpaupack PA
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    Chamfer the hole as well... so u dont get chips and stress cracks..

  4. #4

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    Thank you!
    07 LSV

  5. #5
    Join Date
    May 2008
    Location
    Minneapolis
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    507

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    I used a diamond hole saw use for tile to get through the gelcoat then drilled through the rest forward with a regular wood bit much quicker

    I figured if it wont chip ceramic tile it shouldn't chip the gelcoat
    2007 Outback V

  6. #6
    Join Date
    Jan 2008
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    Pensacola, FL
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    1,537

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    Everything posted above. Use tape on the hull prior to starting, start on the outside. The drill bit will work its way through, then finish from the inside. Start both sides in reverse. Once done, use some sand paper and round (or chamfer) the edges of the gel coat, this will help prevent gel coat cracks. Measure several times, you only get one shot.
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