Drilling fibregalss

[colhel]

I want to drill a hole in the cockpit seat about 15mm dia. I'm thinking a hole saw would be best. Can anyone advise please?

 

[richardabeattie]

What's wrong with a 15mm flat blade drill bit?

 

[Tranona]

Holes saw is best. Problem with flatbit is keeping control over it and not chipping the gel coat. Could be OK in a pillar drill, but not so good freehand.

 

[alan_d]

If you have a reversible drill it is worth starting by rotating the holesaw the "wrong" way until you are through the gelcoat, that way you will get less chipping at the edge.

 

[nigelmercier]

What's wrong with a 15mm flat blade drill bit?

Just about everything.

Hole saw is the right tool, from both sides if possible. Go slowly, get a bi-metal one if possible.

 

[oldsaltoz]

Taping the area to be drilled will reduce any chipping of the gelcoat, also make sure the drill bit is very sharp.

Good luck and fiar winds.

 

[ruaridhmaccallum]

Cone drill

15mm is quite small for a hole-saw - you might struggle to find one.
Don't even think about using a flat blade bit.
Cone drills (step-bits?) work well in FG. They make a very clean cut, but if it's a thin laminate don't push too far or you'll have too big a hole.
Search 'cone drill' on ebay if you don't know what I mean.
Hope this is some help.
R

 

[colhel]

Thanks everyone!

 

[Modulation]

If you have a reversible drill it is worth starting by rotating the holesaw the "wrong" way until you are through the gelcoat, that way you will get less chipping at the edge.

+1. Had to drill 3 holes up to 35mm dia. I followed advice to start drill in slow reverse fro a bit and got a perfect finisg with no gel coat chips.