drilling in fiberglass
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I need to install a water dump off the transom or starboard side. Whats the proper way to drill a hole through without splitting or cracking the glass? Also what do you use to seal/treat the inside of the hole and seal from water intrusion? Thanks in advance, Derrick
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two things I have always been told
heavy tape over the area to drill. inside and out
second, reverse drill to start with
prevents the gellcoat from chipping. Almost like sanding a hole first.
OH, MOST IMPORTANT
measure three times before you drill once![Smilie](/forums/images/smilies/smile.gif)
make sure you seal it afterwards
heavy tape over the area to drill. inside and out
second, reverse drill to start with
prevents the gellcoat from chipping. Almost like sanding a hole first.
OH, MOST IMPORTANT
measure three times before you drill once
![Smilie](/forums/images/smilies/smile.gif)
make sure you seal it afterwards
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All good hints. Most most most important to check what's on the other side of and how thick where you're drilling in to. Sounds obvious I know, but not many thread mounts have >3" of nut travel! .
And clean everthing wit acetone, acrisol or somesuch.
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And clean everthing wit acetone, acrisol or somesuch.
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A hole saw is needed, go slow so it does not melt the glass, you want shavings. Start outside so that any chips are inside. These have large trim/flanges so you can hide things. I used a one inch and had to use a half circle file to get the exact fit. I could have gotten away without silicone it was so tight.
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Last edited by MitchStellin; 04-27-2004 at 08:41 PM.
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racinbird.
If you can find one, use a forsner bit. (mostly found at a woodworking shop). It has a center point, and two cutting edges (versus a "V" like a regular bit). So it basically is touching on 3 points when you start. Run it in reverse first and you will get a perfect pre-cut circle. Gives a square cut hole.
Then run some 3m 4200/5200 in the hole along with the screw you plan to use.
Bob
If you can find one, use a forsner bit. (mostly found at a woodworking shop). It has a center point, and two cutting edges (versus a "V" like a regular bit). So it basically is touching on 3 points when you start. Run it in reverse first and you will get a perfect pre-cut circle. Gives a square cut hole.
Then run some 3m 4200/5200 in the hole along with the screw you plan to use.
Bob
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I forgot about those, nice tool to have, I need to get one, they do work well and can make a perfect size hole. Remember to keep checking so you don't go too large.
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Go to any local plumbing supply house and sk for a Lenox Carbide tipped hole saw. No matter how you hit the fiberglass or at what speed yo will not chip it. Most normal holesaws will but carbide will not - they are not that expensive.