Cutting Fiberglass?

I need to cut the center section out of a large radial cowl, and enlarge the opening in some fiberglass wheelpants.

I'd appreciate input on the best tool to use to get a good clean cut. A specific dremel bit perhaps?

TIA PCPhill

Reply to
PCPhill
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Use a spiral cutter to come close, then a sanding drum to trim it down. Dr.1 Driver "There's a Hun in the sun!"

Reply to
Dr1Driver

But do not forget the mask and goggles - fibreglass dust and particles are not to be trifled with - very nasty

David

Dr1Driver wrote:

Reply to
quietguy

Advice and warning noted. I need to stop living dangerously, one day it's going to come back and bite me!

Thanks DR1Driver and David

PCPhill

Reply to
PCPhill

I can't remember who makes them, but there are small bits made with carbide grit fused to steel bases that work REAL well for this. They don't clog and cut very well.

Reply to
Paul McIntosh

I cut holes in a beautiful Great Planes Wagstaff Extra cowl by starting in the center of the material to be removed with a drill.

I enlarged the hole using whatever worked.

I approached the edges with a Dremel grinding stone--the red ones, that are pretty rough.

Final shaping of the holes and smoothing of the edges were done with various grits of sandpaper mounted on various roundish things (dowels, magic markers, brass tubes--whatever seemed best for the radius I wanted).

I think Harry Higley shows another technique for removing great big pieces of cowls, but I may be mistaken. The picture I seem to misremember showed lots of drill holes marking out the area to be removed. After drilling them, you connect the dots with a hobby knife, then go to work on the edges to round them out.

I think I may also have used cut-off wheels to cut big chunks out of the bottom of the cowl.

The whole strategy I envision is to creep up on the desired line in small steps rather than to try to make one perfect cut. Of course, if you've got a CAD-driven Dremel, nevermind what I just said. :o)

Marty

Reply to
Martin X. Moleski, SJ

Thanks Martin,

I picked up a spiral cutter for my dremel this AM, per DR1Driver's suggestion. I already have a drum sander bit, so if I don't get too aggresive with the cutting I should be alright. Fortunately I just have to cut out the big center disk of the cowl, which is easy to see. No funky measurements for the cylinder or carb, as this one is using electrons.

I need to get the Higly books someday, I've heard nothing but good about them. Anyone selling some used ones cheap out there?

Phill

Reply to
PCPhill

In article , Paul McIntosh writes

Permagrit.com

Reply to
Richard Crapp

I use one of the grinding stones for the dremel tool. They work great. Cuts fast. Won't fill up, and the stone isn't effected by the f'glass. I also use a sanding drum to get the edges straight. The carbide cutters are a pain in the $#^! The spiral cutter is too hard to control and gets away from me.

Reply to
jeboba

When I need to make a cutout yet keep both parts ( a hatch ), I use a razor saw. I start by marking out the cut then scoring along the lines with an Xacto and straight edge, then switch to the saw. The saw will stay in the groove made by the knife. This method makes the smallest kerf, at least smaller than with a cutoff wheel in the Dremel.

Reply to
PS2727

I have a 10" diameter circle to play with in the middle of the cowl. Sounds like experimentation may be my best bet (and practice!)

PCPhill

Reply to
PCPhill

It sounds pratical for straight cuts, but I have a circle to cut out.

Thanks, PCPhill

Reply to
PCPhill

Let us know what works best for you.

Marty

Reply to
Martin X. Moleski, SJ

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