How to cut a hole in fiberglass cap???

[tomhamrick]

I am replacing the original lights on my Eagle with the LEDs from Silver Eagle. The originals have a cylinder shaped protrusion on the bottom that goes through a round hole in the cap. The new lights have a rectangular protrusion that is slightly longer than the hole. I need to make the hole bigger and square the corners. What is the best tool to cut a square hole? Someone told me that if I cut with too fast a tool and get the fiberglass hot is can cause it to crack. You guys are great. Thanks in advance for your help!
Tom Hamrick
1984 Eagle 10S

[gumpy]

If you're just enlarging an existing hole and squaring the corners, I'd use a file and file it away. Triangular files work well for making square corners.

I found that the best tool to cut fiberglass was a diamond wheel used for ceramic tile mounted in my 4 1/2" grinder. May be too big for the holes you're talking about. I also used jigsaw with decent results, but you need to get a 20 tpi blade, and the fiberglass eats the blade in short order.

craig

[makemineatwostroke]

I used a rotozip with a laminate bit to install mine with worked good.Be careful not to run the batteries down showing off the new lights as they do look good at night

[Utahclaimjumper]

Small hand held dye grinder with a thin abrasive blade available everwhere gets to most places and works well.>>>Dan

[Hartley]

Air Powered "Body Saw" with 18 or 24 tpi blades. ( about 1 1/2 inch long blades )

Makes intricate cuts and is small enough to do fine work in tight places.

I use mine sometimes making square holes out of round ones in fiberglass and metal.


Tools is FUN ! 

[Stan]

Cracks propagate from sharp corners. If possible, drill a hole (1/4" ?) at each corner before you cut to the hole, regardless of what you use to do the cutting.  That will leave a radius in the corner. Fibreglass is not hard to cut, but it is very abrasive.

[Chaz]

I'm with Dave. For this a body saw would be great. I have all sorts of cutting equiptment and this is what I would use. They can be bought cheap from "cheap tool" sources.
  Chaz

[captain ron]

As Stan says it's best to have radius corners if at all possible. If the hole you need will be covered by excess material of the light try to get as large of a radius as you can. My preference for cutting would be to drill all 4 corners with as large a radius as you can then use a cutoff wheel to connect the holes.

[Hartley]

If you are worried about eventual cracks and water migration you could
get a small amount of fiberglass resin and hardener at almost any autoparts
stores or marine and even some ace hardware stores and dope up the edges after
you make the cuts. Also allows you to build up imperfections too...

Dave....

[FloridaCliff]

Tom,

I used an air body saw on my caps, worked great,

Even with the air you can feather the speed.

HF has a decent one for non commercial use.

Be careful how you cut on that "good looking" Eagle.

Cliff

[Jerry32]

I also found the body saw the best little tool for cutting alll types of material. Jerry

[makemineatwostroke]

Stan and Charley are right about the radius corners thats way Richard at R&M told me to do it and with a fine tooth blade like Dave suggested if I didn't have a rotozip or router with a Formica bit

[tomhamrick]

Thanks for all the great replys. Hopefully I will get to work on this Saturday now that I am armed with your help!
Tom Hamrick