drilling in fiberglass
04-27-2004, 07:01 PM
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drilling in fiberglass
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
04-27-2004, 07:38 PM
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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
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
make sure you seal it afterwards
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04-27-2004, 08:32 PM
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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.
And clean everthing wit acetone, acrisol or somesuch.
04-27-2004, 08:36 PM
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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.
Last edited by MitchStellin; 04-27-2004 at 08:41 PM.
04-27-2004, 08:44 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
04-27-2004, 08:51 PM
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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.
04-27-2004, 11:05 PM
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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.
