Drilling through gelcoat from behind

[UncleSpidey]

I've been searching the threads on this one, but I haven't yet found an answer....

I'm mounting some electronics on top of the helm console. I want to bore a 1" hole to pass the wiring, as well as a few smaller holes for the mount. The problem is, the angle of the windshield is preventing me from getting the drill perpendicular to the console (even using a right angle drill) from the topside. There's just too little height between the top of the console and the windshield for everything to fit. So it looks like my best option would be to start from the underside of the console and drill up. I'm worried this might damage the gelcoat on the topside as this will be the last thing I'm drilling through. When starting a hole on the gelcoat side, I'll initially run the drill backwards to "burn" through, but I haven't ever come from the opposite side before.

Anyone have any thoughts on this??

 

[bob johnson]

Re: Drilling through gelcoat from behind

can you clamp a solid piece of wood or plastic down tight and flush with your helm..
also Id use one of the hole cutting saws or drills instead of a 2 flute twist drill . the wood bits grab abnd cut the outer edge while maintaining being centered with the point in the middle.....it should give you a clean hole.

use a brand new drill....I think they are called spade wood drill bits...

if you had something to practice on first you could see how it comes out.

you can practice with a smaller hole with those bits, becasue the center acts as a pilot.....so the drill doesnt walk sideways.

good luck

bob

 

[oops!]

Re: Drilling through gelcoat from behind

i would remove part of the windsheild

the problem is that where the windsheild mount is, is a common pooling spot for gellcoat when they spray the cap in the mold. pooling means thick gellcoat.

i think your going to chip the gellcoat when you push thru.

the chips wont be bad....but it will be a jagged edge.

there is a piping kind of stuff you can buy to place around the new hole....but if you are really worried about chipping the gell.....remove the section of windsheild

 

[smokeonthewater]

Re: Drilling through gelcoat from behind

One option would be to drill the hole undersize and finish with a carbide burr on a dremmel or die grinder

A really slick trick is to drill JUST the center hole for the hole saw, and then use a steel rod the same diameter as the drill bit.... put the hole saw on TOP of the hole and the drill UNDER it. Drill the final hole just as you normally would but but pulling the drill instead of pushing.... Good luck!

 

[UncleSpidey]

Re: Drilling through gelcoat from behind

A really slick trick is to drill JUST the center hole for the hole saw, and then use a steel rod the same diameter as the drill bit.... put the hole saw on TOP of the hole and the drill UNDER it. Drill the final hole just as you normally would but but pulling the drill instead of pushing.... Good luck!

Now THAT'S an interesting idea. Gotta think about it a little bit, but we might just have the winner. Thank you.

If there are chips that develop, then maybe a cable cap would do the trick at covering it up and probably look more finished.

http://www.johnnyspond.com/big-jon-white-and-black-double-cable-cap.html

 

[smokeonthewater]

Re: Drilling through gelcoat from behind

BTW if you do this, remember that when pulling, reverse is forward and forward is reverse..... a bottle of windex also makes a good cutting fluid for fglass/gelcoat. Less chipping AND less dust down your collar.