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Need to drill a hole, don't want to ruin gel coat


msuwaterski

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Hey gang. I just got my new to me SSLxi home and need to make a few changes before putting her in the water. Right now the center ballast is bringing water in through a fitting on the drain plug in the bottom of the boat (which I am OK with), but the drain line uses the bilge hose through hull fitting and the bilge is hooked to nothing. I am not comfortable with that, so I want to add a through hull fitting for my drain line.

My question is, how do I drill the hole in the side of the boat without destroying my gelcoat?? What type of bit do I use, wood or metal? Do I use tape to help with spydering?

Any and all help is greatly appreciated.

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Lots of tape in alternating directions over the spot you need to drill. Start the hole by drilling in reverse and pressing hard. Use a really good sharp bit - I use good sharp (new) titanium tipped bits when I do this. After the indent is through the gel by drilling in reverse, then switch direction and cut your hole all the way through. Speed is good. You'll get chipping if you use a dull bit and it hangs up or the drill jitters.

It's scary - but not very hard.

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Lots of tape in alternating directions over the spot you need to drill. Start the hole by drilling in reverse and pressing hard. Use a really good sharp bit - I use good sharp (new) titanium tipped bits when I do this. After the indent is through the gel by drilling in reverse, then switch direction and cut your hole all the way through. Speed is good. You'll get chipping if you use a dull bit and it hangs up or the drill jitters.

It's scary - but not very hard.

Did you use a hole saw also or a regular titanium tipped bit? What type of tape, masking?

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I would not press too hard... That's what makes hole saws bind.

Make sure the hole saw has a pilot bit and there is nothing behind where you are drilling. (I know...I'm just sayin')

Tape off the area. Tape a shopping bag below the hole to control the itchy dust.

Drill the 1/4" pilot hole first then put the hole saw on the arbor and drill backwards with even pressure till you get through gel coat (+/- 1/16"-1/8")

Then drill as normal. When finished remove the tape and take a piece of sand paper (100-120grit)and round the edge of the hole slightly on the outside. Apply some 100%silicone to the back side of the fitting and tighten. It may help a novice to apply some tape about 1/2" outside the flange on the gel to help control the silicone. (some get carried away with the caulking gun.) make sure you have some rubbing alcohol to clean up excess wet silicone. (OLD plumber's trick--I may have to charge you for that one...)

Good luck!

Patrick

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Thanks everyone for the pointers. I said my prayers, took a deep breathe, and put the drill to the side of my boat this evening. I did everything as instructed and it was a piece of cake. I don't even think it took more than a minute. I even used the rubbing alcohol tip, just to see if it worked of course :whistle:

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Thanks everyone for the pointers. I said my prayers, took a deep breathe, and put the drill to the side of my boat this evening. I did everything as instructed and it was a piece of cake. I don't even think it took more than a minute. I even used the rubbing alcohol tip, just to see if it worked of course :whistle:

ANYTIME!!

See..that was painless!

Glad it all worked out!

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  • 2 weeks later...

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