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Intense

Drill holes in fiberglass

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Intense

Hey all,

I'm wanting to add some pop-up cleats to my 'Bu. Is there a good method for drilling to holes, such that I don't damage the surrounding fiberglass? IE cracks and such

Thanks!

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bobofthenorth
Hey all,

I'm wanting to add some pop-up cleats to my 'Bu. Is there a good method for drilling to holes, such that I don't damage the surrounding fiberglass? IE cracks and such

I put masking tape over the area, mark the tape and drill through the tape. Its really hard getting up the nerve to drill the first hole.

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my malibu

masking tape and just make sure to start the drill bit in reverse

prevents cracking once though the gel coat back to forward

don't worry it just a hole Cry.gif

also if you are installing pop-up ones get a dremel tool with a spiral cutter

works well for making ovals, etc.

Edited by my malibu

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chadwick02

I have drilled plenty of holes using a good sharp bit, started it in reverse, then finished it in forward. Mask it for sure. I've done a bunch of depth finders and other hardware like that (most of them located in non-obvious spots such as low on the transom). I've never seen any of those spider crack or experienced any of the horror stories that I have heard of. That being said, last year I had to drill (8) 1/2" holes right in the top of my gunnels to install my tower. I was mortified to drill these, and wanted to make sure I did it right since it was such a big hole in such a obvious spot that would be under a fair amount of force. Long story short, there is a product out there called the unibit. The idea behind the uni bit is that it gradually makes the hole bigger which makes for better drilling in the first place, but it also helps "round" or "smooth" the edges of the hole to help avoid spider cracking. Not sure, but it might be over kill for what you want. They offer the unibit in several sizes, so I would think one would be small enough for what you want. A search here for "unibit" should turn up a little info on it.

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bigD
A search here for "unibit" should turn up a little info on it.

Plus1.gif

Thats what I used,with a little duck tape.

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99response

Use hole saws for anything bigger than 3/4"

-Chris

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vette-ski

I need to pop some holes in the bottom for ballast pump install. Anyone have an opinion if it's better to drill from the outside in vs. inside out (since I'll have room to go either direction). If you drill from the inside out, is there more of a risk of chipping the gelcoat when the bit comes through?

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wienrdog

Are you using a hole saw & does it have a pilot bit?

If you are using a hole saw...

I have seen a recommendation for bottom holes to start from the outside. But when the pilot bit punctures the inside, and before the hole saw goes all the way through, to drill about 1/8" the inside with the hole saw, then finish from the outside.

This helps to prevent chipping on either inside or outside.

I have not done this yet, but plan on using to install a PP paddle wheel later this spring.

Edited by weinrdog

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JAGMAN

Whatever bit/approach you decide on, just make sure you use a high quality, new, sharp bit. Don't use one of the cheapo bits that you get in a kit of 50 drill bits for $15.

If you use a hole saw, make sure it has a pilot bit as well, you'll regret it if it doesn't (in addition to high quality, new, and sharp).

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Intense
I have drilled plenty of holes using a good sharp bit, started it in reverse, then finished it in forward. Mask it for sure. I've done a bunch of depth finders and other hardware like that (most of them located in non-obvious spots such as low on the transom). I've never seen any of those spider crack or experienced any of the horror stories that I have heard of. That being said, last year I had to drill (8) 1/2" holes right in the top of my gunnels to install my tower. I was mortified to drill these, and wanted to make sure I did it right since it was such a big hole in such a obvious spot that would be under a fair amount of force. Long story short, there is a product out there called the unibit. The idea behind the uni bit is that it gradually makes the hole bigger which makes for better drilling in the first place, but it also helps "round" or "smooth" the edges of the hole to help avoid spider cracking. Not sure, but it might be over kill for what you want. They offer the unibit in several sizes, so I would think one would be small enough for what you want. A search here for "unibit" should turn up a little info on it.

So you start drilling the hole in reverse rotation? Will the bit even remove any material? How far do you drill in reverse before you start drilling forward? I assume it's once you get past the gelcoat....

If I use this unibit, do I follow the same procedure? Drill in reverse until I get past the gel coat, then drill forward?

thanks!

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Mechmaster
I need to pop some holes in the bottom for ballast pump install. Anyone have an opinion if it's better to drill from the outside in vs. inside out (since I'll have room to go either direction). If you drill from the inside out, is there more of a risk of chipping the gelcoat when the bit comes through?

Drill the pilot hole from the inside. Tape off the bottom of the hull, and drill the hole saw (using the pilot) from the outside. Start the hole saw in reverse, then when you pentrate the gel, finish the hole in forward.

There will be some chipping around the hole initially drilled from the inside; however, this is removed when you drill the hole out (it leaves with the plug).

Starting with the pilot hole from the inside ensures that you end up with the hole in the correct location with respect to the interior. Be sure to check the location of the trailer bunks.

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Mechmaster
I have drilled plenty of holes using a good sharp bit, started it in reverse, then finished it in forward. Mask it for sure. I've done a bunch of depth finders and other hardware like that (most of them located in non-obvious spots such as low on the transom). I've never seen any of those spider crack or experienced any of the horror stories that I have heard of. That being said, last year I had to drill (8) 1/2" holes right in the top of my gunnels to install my tower. I was mortified to drill these, and wanted to make sure I did it right since it was such a big hole in such a obvious spot that would be under a fair amount of force. Long story short, there is a product out there called the unibit. The idea behind the uni bit is that it gradually makes the hole bigger which makes for better drilling in the first place, but it also helps "round" or "smooth" the edges of the hole to help avoid spider cracking. Not sure, but it might be over kill for what you want. They offer the unibit in several sizes, so I would think one would be small enough for what you want. A search here for "unibit" should turn up a little info on it.

So you start drilling the hole in reverse rotation? Will the bit even remove any material? How far do you drill in reverse before you start drilling forward? I assume it's once you get past the gelcoat....

If I use this unibit, do I follow the same procedure? Drill in reverse until I get past the gel coat, then drill forward?

thanks!

With respect to smaller holes, tape off the location and mark your holes. Using a new (sharp) bit, drill in reverse until you pentratate the gel, then switch to forward to finish the hole.

Use a countersink bit like this:

countersink-bit.gif

and in reverse gently chamfer the hole edges.

FWIW, I've heard that the UniBit works really well, but I haven't tried it.

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tcody

Where did you get your pop-up cleats. I want to add 2 more to my SS LXI. Whistling.gif When you install them I would like to see how you do it. I an only about 45 minutes form you and would like to see the install. Thumbup.gif

Good luck

TLC

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Mechmaster
Where did you get your pop-up cleats. I want to add 2 more to my SS LXI. Whistling.gif When you install them I would like to see how you do it. I an only about 45 minutes form you and would like to see the install. Thumbup.gif

Good luck

TLC

Look here: http://www.firstchoicemarine.com/p-574-nea...flush-4-12.aspx

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