Drilling holes in Fiberglass

[Hookjaw]

Hello, I have a Ranger 619 FS and I am currently mounting Scotty DownRiggers. I need to drill a 1.125 or 1/18 inch hole for the Scotty receptacle. The hole will be on the front side of the rear splash well to prevent water intrusion. Just wondering , do I use a small pilot hole and then a spade bit or try to find a 1 1/8 hole saw?

[Huntindave]

I would NOT use a spade bit. Never tried a spade bit but I don't imagine you would be pleased with the results.

A hole saw is what I'd use. Drill thru with the pilot only, then put the drill in reverse and "score" thru just the gel coat while running in reverse. Put the drill in forward and finish drilling all the way thru.

If you have the room and means to put a wood backer block against the far side of the fiberglass while doing the drilling, it will help avoid tear out when breaking thru.

[Leinie]

What he said X 2

[REW]

https://www.homedepot.com/p/Milwauke...9820/204994422

[CI_Guy]

What Dave said plus I always put masking tape on the area I'm drilling to help prevent chipping of the gel coat.

[AllenW]

Originally Posted by CI_Guy

What Dave said plus I always put masking tape on the area I'm drilling to help prevent chipping of the gel coat.

Ya, same here, it seems to help.
Go slow and take your time.

Al

[REW]

In addition, even if using an excellent hole saw, after drilling your pilot hole; run the hole saw in reverse for a few seconds to get through the gel coat. The hole saw in reverse will still get through the gel coat, but there will be a much smaller chance of chipping the gel coat.


After getting through the gel coat, you can flip the direction and drill in the normal fashion for the main fiberglass layers.


Also, as you feel the bit began to break through the last of the fiberglass, reverse the bit again to help minimize any tearing out on the back side of the fiberglass.

Good luck

[Hookjaw]

Thank you all for the expert advice.

[WALI4VR]

Did you read post #2?

Originally Posted by REW

In addition, even if using an excellent hole saw, after drilling your pilot hole; run the hole saw in reverse for a few seconds to get through the gel coat. The hole saw in reverse will still get through the gel coat, but there will be a much smaller chance of chipping the gel coat.


After getting through the gel coat, you can flip the direction and drill in the normal fashion for the main fiberglass layers.


Also, as you feel the bit began to break through the last of the fiberglass, reverse the bit again to help minimize any tearing out on the back side of the fiberglass.

Good luck

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