Drilling Large Diameter Holes in Fiberglass?

[bdeutsch]

I am wondering what most of you use when cutting large diameter holes in fiberglass bodies...say diameters of between 5" to 8". Thickness of the fiberglass is that used on Cobra bodies.

I am looking at a tool called a Hole Pro that looks promising, but wondering if there might be less expensive alternatives without compromising the chances of shattering the gel coat, rough cuts, etc.

As always, membership input is greatfully appreciated.

Thanks,

Bob

[Three Peaks]

A jigsaw usually works great and you can get different grades of blade depending on how smooth you want to make your cut. For protection of your finish, I usually put down at least one layer of heavy tape for the foot of the jigsaw to ride on while you are cutting, then peal it off when you're done.

Rotary tools that look like a Roto Zip would work, but they are hard to control and get a clean and straight cut with.

[thudmaster]

Roto zip with the circle cutting adapter and vaccuum adapter.

[onefastmustang]

When I did it I used a compass to mark and dremel tool with a rotary bit to cut.. worked like a charm.

[flwolfman]

I cut out my headlight holes with a large hole saw. It worked fine. I did this prior to painting the car. Use tape to reduce damage. Hope this helps. Jim

[Bernica]

I'm with the guys above about the RotoZip.
There is another tool out there that is used for cutting large holes in sheetmetal. I have one that I used when I installed Air Conditioning in our house, and occasionally since. Works on the same principal as the RotoZip, and uses rotary-cutting bits, but it's heavy duty and set up only for round holes. It's called a Malco HC-1 Hole Cutter. Mine will cut from 2" to 12".

[bdeutsch]

Thanks to everyone who responded...much appreciated.

In regards to tape, assume masking tape is the best candidate for this?

Also, of the two approaches taken, what has been experience with gel coat chipping?

Bob