Drilling holes in GRP

[jhr]

It's Friday afternoon, ergo time for a gormless question.

I need to drill some holes in the cockpit, to fix a mount for my GPS and for an additional fire extinguisher (a personal tribute to H1) /forums/images/icons/smile.gif/forums/images/icons/smile.gif

Any do's and dont's? If drilling through ceramics, I'd normally do so through a bit of duct tape; is this a good idea with GRP as well? Any thoughts on preventing water ingress through the resultant hole?

SWMBO maintains that I am the original inspiration for the TV programme "DIY - SOS", so all hints, however simplistic they may seem, will be gratefully received.

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[Deleted User YDKXO]

No, its a good question as its very easy to crack and chip the gelcoat with a drill bit. As you say, use a bit of tape and I would drill a small pilot hole first and then drill out the hole with the correct size bit. Use the slowest speed on the drill until the hole is established
To seal the hole just squeeze a little silicone sealant into each hole before you insert the screws and smooth away the excess afterwards with a wetted finger. A piece of kitchen paper towel is handy at this point to wipe your fingers

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[dog]

Hi, not sure if this is common practice, but I have found that by using a counter-sink bit to 'fair away' a small portion of the brittle gelcoat works well (after initial hole drilling). It stops the screw from cracking the gelcoat as it goes in, and only needs to be slightly larger than the diameter of the hole you are drilling. As said before a dab of sealant when fitting the bracket/fitting.



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[jhr]

Thanks, guys - very helpful.

Await my post-weekend posting: "Turning your boat into a colander, for pleasure and profit"

)

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[Talbot]

you didnt say how big the hle was going to be- if just for screws, just make sure that the gel coat is drilled out larger than the screw size, otherwise it will chip. the suggestion to use a countersink is good, and will help to prevent drilling through the substructure as well (i.e. leaving you nothing to connect the screw to!!)

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[jhr]

Yes; it's just screws. (Only a bracket for a handheld GPS and a mini fire extinguisher). The countersink is a good idea and I will definitely do it. Whether or not this will prove to be the first DIY job that I don't cock up remains to be seen..........

;o)

Thanks, everyone

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[Guest]

Nuts and bolts are better.....!

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Nigel

<hr width=100% size=1>Medway Motor Yacht Club
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