Drilling and cutting fiberglass, Any hot tip's?

Any tip's about drilling and cutting holes in fiberglass would be greatly apreciated

I have limited experience( installed PPass and tower) but here are a few tips. Always drill from the outside in, if possible. Use masking tape pressed down well over the area you are going to drill / cut and drill through it. Also we found scribing the gelcoat with a compass on the cut line prior to cutting eliminated any spider cracking in the gelcoat ( along with the masking tape). If possible use a new holesaw even for small holes. We had one that was 3/8 for tower bolt holes and it worked well. PPass holse was like 1 1/2 inch. PS new hole saw made all the difference.

Blue tape. Reverse drill first with a hole saw. Same thing as the compass tip. Use wd40 and drill away.

Are you using a hole saw or just drilling? If your just drilling, try to use a counter sink bit.

(Message edited by oshensurfer on August 12, 2004)

Hold a shop vacuum next to the hole you are drilling. No mess. And yes I agree, use tape.

yea, tape, and a new bit

if you're gelcoat is quality you won't crack it at all, scoring it before isn't necessary.

I did try to drill a second hole with the original holesaw, and it took about 5 times as long, so a new one is probably a good idea.

Oh yeah, make sure you are drilling in the right spot, then double check it about 30 times.

Shop vac is a good idea, long sleeve shirt too (fiberglass dust burns and itches).

As Scott said....DRILL IN REVERSE! I cannot stress how important this is. If you don't you will run the risk of chipping the gel coat around the hole. Drilling in reverse eliminates this problem.

All your help is greatly apreciated. Can you use a jigsaw to cut out holes, I need to cut out a rectangular hole for a stereo, scares the heck out of me. What about a rotozip? Thanks again.

Rotozip works great. Buy good bits for it, you'll need them. And go slow, don't force the bit, it will break. It will wonder a little bit so watch it.

always countersink holes from the gelcoat side to stop spider cracks

If your gonna cut out a hole with a jig saw,roto zip,then you should drill the corners(in reverse).
Sort of a dot to dot trick.

Just my .02 but I wouldn't use a rotozip. They have a tendency to get away from you. Trust me, you don't want to make a mistake on your gel coat. You only get one shot.

If you are using a jigsaw, they make some abrasive blades for composite materials. They are not toothed like normal blades, but have a bead of abrasive welded to the front. I have not used it on fiberglass, but they work really nice on some other materials that don't cut that well with a toothed blade.

As with anything new, try it on a safe place first or on a piece of scrap.

You can use a Rotozip or even a Dremel tool with router bits. I used a Dremel with a cutting attachment and it really helps to keep it stable. Use a fresh bit for each hole - really makes a difference.

I used a regular hole saw to drill the hole in my dash for my defroster vent, and went in forward with no problems, but then again I have a CC, and their gell is really thick.

I used a rotozip to cut 6x9 speaker holes with no problems. Didn't use a drill bit to start either, just used to rotozip. Mask it first, mark the tape and go slow.

Thank's again for everyones help! I think I have enough courage to do it now. Wich tape works best? low tack, tuck,or masking?

Blue painters tape. Use the wide type or it may bind on you.