Drilling into Fiberglass

[KBryant2007]

I am upgrading my radio, and adding an iPOD port. The iPOD adapter that I bought requires a 3/4 inch hold for the jack to be installed. I plan to put it near the radio, but it will require me to drill a hole. What type of bit should I use, and what should I watch out for since I have no room for error.

[cbryan70]

tape it, drill in reverse

[SilviaMan]

I would use a hole saw for drilling and agree with the reverse at least until your through the gel coat.

[willyt]

I believe your supposed to use masking tape as well

[CantRepeat]

Originally Posted by willyt

I believe your supposed to use masking tape as well

I always do and and if I can get to the back I mask off both sides.

The other nice deal if you have a friend, have the hold a vacuum to the area while you are drilling and vacuum up the dust.

[cbryan70]

Originally Posted by cbryan70

tape it, drill in reverse

Originally Posted by SilviaMan

I would use a hole saw for drilling and agree with the reverse at least until your through the gel coat.

Originally Posted by willyt

I believe your supposed to use masking tape as well

There you go. And def use a hole saw. Tape it with masking tape, and use the hole saw in reverse. It will prevent chiping and cracking of the glass.

[Double D]

Originally Posted by cbryan70

tape it, drill in reverse

+2 on this answer......

[FrankSchwab]

1. Tape over it
2. Mark your hole.
3. Using a small bit (1/8 or so), drill a pilot hole. Run the bit in reverse until you're through the gelcoat, then you can switch to forward.
4. Enlarge the pilot hole using a larger bit - based on the next step, a 1/4" bit would work. Start in reverse until you're through the gelcoat, then you can go forward. You could probably start with the 1/4" in reverse, but that's not how I did it.
5. Using a Step Drill, drill the hole. No need to go backwards with these; they make a very controlled hole through the gelcoat. When you get to the 3/4" step, run the drill backwards and use the edge of the next larger step to chamfer and smooth the edge of the gelcoat.

I've done several 3/4" holes on my boat installing pop-up cleats, and this is so smooth and easy that I've never considered using a hole saw, or trying to run a 3/4" twist drill in reverse. The first couple of steps make small holes, but also hold the bit solidly centered in the hole as the next larger step is biting in.

[Barefooter92]

Great advise guys! Never thought this was going to be an issue. I am glad this thread cought my eye. I am going to drill two 5" holes in my glass for speaker install, and install some new rocker switches in front of my throtle. Thanks!!

[ctjahn]

Originally Posted by FrankSchwab

1. Tape over it
2. Mark your hole.
3. Using a small bit (1/8 or so), drill a pilot hole. Run the bit in reverse until you're through the gelcoat, then you can switch to forward.
4. Enlarge the pilot hole using a larger bit - based on the next step, a 1/4" bit would work. Start in reverse until you're through the gelcoat, then you can go forward. You could probably start with the 1/4" in reverse, but that's not how I did it.
5. Using a Step Drill, drill the hole. No need to go backwards with these; they make a very controlled hole through the gelcoat. When you get to the 3/4" step, run the drill backwards and use the edge of the next larger step to chamfer and smooth the edge of the gelcoat.

I've done several 3/4" holes on my boat installing pop-up cleats, and this is so smooth and easy that I've never considered using a hole saw, or trying to run a 3/4" twist drill in reverse. The first couple of steps make small holes, but also hold the bit solidly centered in the hole as the next larger step is biting in.

I agree with the step drill bit...