cutting fiberglass ?

[starfighter]

I'm adding an access door to vent an a/c unit in our Hunter 1.
I'm familiar with tools and have done extensive woodworking, but not fiberglass. I was planning to use a drill start, then a fine tooth power jig saw to finish the round opening. Anything better /
Thanx for any.

[Kevin K]

I just put bigger access doors inside under my back bench using a jig saw with a metal blade. Works GREAT. I used some panel trim to finish it off.

[starfighter]

thanx Kevin.....I feel better about starting the project now.

[Roy in TO]

The oscillating multi tools work good too! I've used the 1/2 round blade. No drill start required, just a steady hand.
Oscillating Multifunction Power Tool w/ Variable Speed

[Byron Kinnaman]

The very best too I've ever found for cutting fiberglass is Dremel's zip tool attachment. Smooth and easy to control. No chip out.

I couldn't remember the exact name. Here it is.
This with the dremel motor makes almost perfect cut.

[rabbit]

Down cutting or down clearing (same thing) saber saw blade (in the range of 12 to 20 teeth per inch does a good job from the face side which is of course also the gelcoat side.

jack

[Andrew Gibbens]

A fine-tooth metal blade in a jigsaw does OK for small cuts but it will get wrecked fairly quickly and will always be a bit grabby. The hot-knife-through-butter tool is a RIFF jigsaw blade like the well-work example below. Its grit-coated edge cuts forever and is very smooth and steerable. They are a bit of a speciality item but are useful for cutting any very hard material.

[papa-t]

Nice looking job there Kevin

[Raz]

If you drill a hole for a jig saw blade, drill it in the waste area as twist drill bits tend to chip out gelcoat. Raz

[starfighter]

Got 'er done !!!
I did just use my jig saw W/ a many toothed blade after making a start hole. Came out pretty slick.
I put a portable a/c unit in a closet and vented out through a small (5") round access port. When A/C is needed, I just open the port and the closet door, and crank it up...
When not in use, it is not obnoxious.
Thanx for all the help........

[Eddie Longest]

I use a multi-tool with a half moon blade. Hold your shop vac near the blade while cutting and it collects most of the fiberglass dust.
Eddie

[mary and bob]

I use an air powered die grinder with a thin 2" cutting wheel.

[Brian B-P]

Originally Posted by mary and bob

I use an air powered die grinder with a thin 2" cutting wheel.

An abrasive cutting wheel (like a rotary version of Andrew's blade above), or a toothed saw blade?

[Brian B-P]

Originally Posted by Roy in TO

The oscillating multi tools work good too! I've used the 1/2 round blade.

Originally Posted by Andrew Gibbens

The hot-knife-through-butter tool is a RIFF jigsaw blade like the well-work example below. Its grit-coated edge cuts forever and is very smooth and steerable.

Has anyone tried an abrasive blade in an oscillating tool?

[Jared J]

I use a 3/4" blade in a dremel oscillating tool.

[mary and bob]

Abrasive disc in the die grinder is what I used. I've used it to widen the rear window opening when I installed a Scamp window in our Uhaul, and to cut an opening for a new power converter, a storage opening, and increase the opening size where the ice box was to replace it with a dorm fridge. It's a thin disc, worked good, but made a lot of dust. For the corners of the openings I used a toothed hole saw to get a round corner.

[Brian B-P]

Originally Posted by mary and bob

Abrasive disc in the die grinder is what I used.

Thanks Bob

[chuyler1]

ALWAYS ALWAYS ALWAYS

Wear a respirator when working with fiberglass. You do not want to inhale those dust particles!

[fcharlan]

I installed an air conditionned and did the holes with a small jig saw with a metal blade. Worked great.



Also did exterior holes the same way...

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