Best Tool For Speaker Holes?

[Sailing Steve]

We're about to install some surface mount speakers in the cockpit.  Any recommendations as to what tool one should use to cut the holes in the fibreglass?  I don't want to run any unnecessary risk of chipping the fibreglass.

Thanks.

[Roc]

I used a hole saw bit the diameter that I needed (I think it was 4" for my cockpit speakers).  Nothing special about it.  You can get them at any home improvement store.  I borrowed the bit I used because they are not cheap, at the larger diameters.

[Jim Price]

I have used a RotoZip tool in the past.  Drill first pilot hole and follow your outline.  I tape the edges on the lines to prevent cracking.  Can use Dremel tool for clean up.  Just make sure you have not set cutter too deep and know what is behind your area.  The high speed of these two tools will do a good job with fiberglass and the core.  Just creates a whole bunch of dust!!

[rirvine]

I have successfully used a Dremel and their radius attachment to cut larger hole is fiberglass (3" radius).  Drill a small hole at the center of the larger hole, set the correct radius, adjust the cutting tools to be as short as possible (so it just cuts throught the material) and away you go.  Gives you a well finished hole.

[Kyle Ewing]

There will be a lot of dust.  I've used a vacuum to help control it.

[wind dancer]

I had a hole saw the right size, but was missing the arbor for it.  So, I pulled out the dremel, which worked fine, though the hole wasn't perfectly round.  Kyle hit the nail on the head about the vacuum.  Expect to create a lot of dust.

[Phil Spicer]

If you tape the area to be cut, you can reduce chips & cracks. If you are using a hole saw you can slowly run the drill in reverse to get through the tape & gel coat, then switch the direction to forward & cut the glass. A vac is a must & you can try to tape a plastic bag on the back side of the area of the cut (if you can get to that area). That will catch the dust that will fall into the boat.

[mainesail]

1) Use the correct size hole saw & mandrel from either Starrett or Lennox.
2) Use a 1/2 drill that has some power! Drilling through fiberglass is tough work on a 3/8 drill.
3) To avoid chips tape the surface with blue tape then drill the center pilot hole.
4) When starting the hole start the hole saw in REVERSE and keep it in reverse until you get through the gelcoat layer!

#4 Is a little trick I learned from one of the workers at Hinckley Yachts! Starting in reverse will minimize any gelcoat chips and with the tape you'll be fine! This "reverse" trick works with any size hole saw and also works of fabric headliners etc..

Tip #5 Buy a standard size marine speaker like A 5 1/4 or 6 1/2. You will eventually need to replace them and want a standard size! Consult the manufacturer for the proper hole saw size as a 5 1/4 or 6 1/2 inch speaker does not use a 5 1/4 or 6 1/2 inch hole saw etc...

[Sailing Steve]

Thanks everyone for the excellent information.  I will make use of the reverse drill technique the next time I drill into the gel coat.