Fiberglass Hole Saws

[l008com]

I just spend a little time researching, and it's clear to me that I need a "grit" style hole slaw. Diamond or carbide, either will cut through fiberglass no problem. Grit style hole saws smoothly grind their way through, instead of toothed hole saws, which tear their way through the cutting material. I need a 3.75" saw to cut two holes for cup holders. And I need a 5" saw to cut two holes for speakers. 4 holes total. Which is why I don't want to spend the $60+ each, for the two saws.

Any ideas?
I've googled around tool rental places, but they seem to only rent power tools and equipment, not small stuff like this. I don't really want to buy, use once, clean, and replace. Autozone has a nice tool rental situation, too bad they don't have hole saws.

 

[willamettejeff]

Re: Fiberglass Hole Saws

Cut many a hole in fiberglass boats with a regular hole saw including the sizes you mentioned. Bi-metal is best as fiberglass is very abrasive. Trick is to cover the area with masking or blue painters tape first and run the saw in reverse after the pilot hole is through to score the gel-coat for the size of the hole before proceeding. Finish off by sanding the edges of the hole smooth before removing the painters tape. This procedure will prevent chipping of the gel-coat.

-- Jeff

 

[willamettejeff]

Re: Fiberglass Hole Saws

Had an additional thought. You could always sell the hole saws after your done on Craigslist or Ebay, although I keep finding needs for the ones I have and glad I have them. There are of course other ways to cut holes, but none as neat and clean as a hole saw.

 

[Bondo]

Re: Fiberglass Hole Saws

Cut many a hole in fiberglass boats with a regular hole saw including the sizes you mentioned. Bi-metal is best as fiberglass is very abrasive. Trick is to cover the area with masking or blue painters tape first and run the saw in reverse after the pilot hole is through to score the gel-coat for the size of the hole before proceeding. Finish off by sanding the edges of the hole smooth before removing the painters tape. This procedure will prevent chipping of the gel-coat.

-- Jeff

Ayuh,... Ditto that,... Nothin' Special....

 

[oops!]

Re: Fiberglass Hole Saws

Cut many a hole in fiberglass boats with a regular hole saw including the sizes you mentioned. Bi-metal is best as fiberglass is very abrasive. Trick is to cover the area with masking or blue painters tape first and run the saw in reverse after the pilot hole is through to score the gel-coat for the size of the hole before proceeding. Finish off by sanding the edges of the hole smooth before removing the painters tape. This procedure will prevent chipping of the gel-coat.

-- Jeff

double ditto that.....i do it all the time

 

[Yacht Dr.]

Re: Fiberglass Hole Saws

I just spend a little time researching, and it's clear to me that I need a "grit" style hole slaw. Diamond or carbide, either will cut through fiberglass no problem. Grit style hole saws smoothly grind their way through, instead of toothed hole saws, which tear their way through the cutting material. I need a 3.75" saw to cut two holes for cup holders. And I need a 5" saw to cut two holes for speakers. 4 holes total. Which is why I don't want to spend the $60+ each, for the two saws.

Any ideas?
I've googled around tool rental places, but they seem to only rent power tools and equipment, not small stuff like this. I don't really want to buy, use once, clean, and replace. Autozone has a nice tool rental situation, too bad they don't have hole saws.

Why not just cut them with a hand saw ?

I installed 2 speakers with my brother in my last boat with nothing but a Drill hole and a few coping saw blades and a few hack saw blades.

They do sell tools to do this by hand you know ..

Sure it took more then 2 min with a $40 hole saw .. but we had them speakers hooked up by dinner time ..

YD.

 

[ondarvr]

Re: Fiberglass Hole Saws

A jig saw will do it with a grit edge blade.

 

[l008com]

Re: Fiberglass Hole Saws

A jig saw will do it with grit edge blade.

The problem is that 3.75" is a pretty tight radius for a jigsaw. And the cupholder has a pretty small lip. So it really has to be an almost perfect circle.

 

[Georgesalmon]

Re: Fiberglass Hole Saws

As above, I was in the fiberglass business for 35 years and every company used just toothed carbide hole saws. Tried the grit ones but were way to slow and didn't last long.

 

[ondarvr]

Re: Fiberglass Hole Saws

3.75” is easy, I've don it hundreds of times.

When we need to drill a lot holes the same we will special order grit edge hole saws in that size, but if there is the odd hole and we don't have one in that size we just use a jig saw or a regular hole saw. You can use the metal cutting scroll type blades if needed, they are skinnier and turn corners easier. If you are worried about chipping, cut the hole slightly smaller than needed and use a barrel sander to bring it out to the correct diameter.

 

[ondarvr]

Re: Fiberglass Hole Saws

As above, I was in the fiberglass business for 35 years and every company used just toothed carbide hole saws. Tried the grit ones but were way to slow and didn't last long.

They use both, and I have both in many sizes, it just depends on what your doing.

Fresh, new toothed holes saws can grab and chip the edge, sometimes it's an issue, sometimes it's not. That's why running it backwards to start works so well.