Cutting the Side Panels on a 26M Pedestal

[Zavala]

What is the best way to cut or drill the plexiglass side panels on the 26M pedestal? I'm afraid I'll end up shattering it into thousands of tiny pieces. Do you need to tape the surface (both sides?) before cutting? Any advice is appreciated.

[DLT]

I've drilled it with an ordinary drill press using ordinary bits...

I've also used a hole saw on the windows, to mount a vent... I was drilling from the outside and the inside did chip a little bit. But, going slower probably could have avoided it...

For that matter, I've used a hole saw on the fiberglass, without taping it up (to avoid chipping, as some have suggested) and have never had it chip...

The only time I had a significant problem with chipping was using a big (3/4 I think) drill bit, drilling through the transom. Here, it chipped pretty bad, but I was covering it anyway, so it wasn't a big deal.

Bottom line, if you are drilling a small hole, just use an ordinary bit.

If you are drilling a larger hole, use a hole saw. They work great...

If you are real worried about chipping, go ahead and tape it up. Although, I'm not sure the tape can prevent the little bit of chipping I got on the plexiglass windows... Here, probably just need to go slow and let the drill bit cut, rather than chip, as it breaks through...

Also, be sure to tape it up, if there is any possibility of the drill (or anything else) scratching the piece.

[Catigale]

....and if you are thinking of making lots of holes , look into getting a Dremel tool before you buy buy umpteen hole saws like me.

I have used a Dremel a few times, and my impression is you can control work flow much better than a hole saw....perhaps someone who has used both extensively can comment with more certainty.

[waternwaves]

as a side note on drilling with a hole saw through fiberglass

to minimize wander of the large bit, epoxy a small block of hardwood onto the backside where the center pilot hole goes... this will lessen the tendency for the bit to wander and change face angle for the boring bit.

[Richard O'Brien]

buy a special plexi jigsaw blade unless you have a bandsaw which is far better. do not use a metal blade as it will just melt and re-fuse behind the cut. Keep the paper on, but do not expose it to sunlight or it will not peel as easily. When your all done sand the edges to shape, then "shave" them with the edge of a utility blade. do this two or three times. drill, and peel the protective paper. Finally light your propane torch and dance it along the edge. this is called a flame polish, and will leave a high polish superior to the original edges. If it starts to bubble you might consider lowering the flame?

[Zavala]

Thanks all. Several good suggestions -- which is good since I have several holes to make before I'm done!

[Divecoz]

At work we use " Cobra " bits but any step bit works well for Plexiglas and fiberglass without nicks or blowout. We do most often drill from both side's when possible as well . When using holesaw's we either run in reverse thru the gel or use an abrasive holesaw in forward. The epoxy block to keep the bit from "traveling" work's great and IMHO is a must if at all possible.

[DLT]

Divcoz,

Have you ever tried the holesaw, without running in reverse first?

In other words, do you really think it is necessary to run in reverse first? I haven't found that to be required...

I have cut lots of holes, but have never run it in reverse first... I've never had any chipping, with a hole saw on the front side. Maybe I've just been lucky...

With that said, and understanding how nervous many people will be drilling a big hole in their boat, by all means if you prefer - go ahead and run it in reverse. This 'extra' precaution certainly doesn't hurt. Besides, I may have just gotten lucky...

[Frank C]

At work we use " Cobra " bits but any step bit works well for Plexiglas and fiberglass without nicks or blowout. We do most often drill from both side's when possible as well ...

I've never used one of those step-bits, but ponder that triple pak of them on every Costco visit. I'm amazed to hear that they work in 'glass ... would never have imagined that!

[Divecoz]

Divcoz,

Have you ever tried the holesaw, without running in reverse first?

In other words, do you really think it is necessary to run in reverse first? I haven't found that to be required...

I have cut lots of holes, but have never run it in reverse first... I've never had any chipping, with a hole saw on the front side. Maybe I've just been lucky...

With that said, and understanding how nervous many people will be drilling a big hole in their boat, by all means if you prefer - go ahead and run it in reverse. This 'extra' precaution certainly doesn't hurt. Besides, I may have just gotten lucky...

I have only had chipping where gelcoat was an issue ( hole saw too coarse?). So rather than risk it any more. . On Gelcoat I first score it in reverse. I always if at all possible hot glue a block behind the new hole for the pilot bit.
Step Bit's . . the first time I ever used one was for a project at IBM drilling plexiglass after TRYING to use standard twist bits and getting very poor results. ( with hand drills btw. . . . I have seen drill presses use twist bits with no problem's at all)