Tips for drilling through fiberglass and gelcoat?

[twentiesforever]

Hello Members,

I would post in the electronics forum but I feel this can be used for more scenarios. I purchased new speakers to replace the papers ones. I thought the Polk DB510 would be simple drop-ins and I guess they are. The fit in the holes but the screw holes do not line up. Any tips on how to drill through the fiberglass and gelcoat? Im a bit handy but kind of terrified of cracking a big piece and messing my beauty up. Tips?

 

[Murf'n'surf]

It's a piece of cake. Start your drill backwards with the drill bit to score the gel coat, then switch to forward and drill the hole. Covering the area in blue masking tape can help to mark where you are drilling.

 

[twentiesforever]

It's a piece of cake. Start your drill backwards with the drill bit to score the gel coat, then switch to forward and drill the hole. Covering the area in blue masking tape can help to mark where you are drilling.

Excellent. Thanks for the reply. I will do this carefully tomorrow.

 

[swatski]

Hello Members,

I would post in the electronics forum but I feel this can be used for more scenarios. I purchased new speakers to replace the papers ones. I thought the Polk DB510 would be simple drop-ins and I guess they are. The fit in the holes but the screw holes do not line up. Any tips on how to drill through the fiberglass and gelcoat? Im a bit handy but kind of terrified of cracking a big piece and messing my beauty up. Tips?

If you want to feel better - observe a couple of factory made orifices/holes... Most of them are so bad, you can hardly do any worse...

 

[eticket]

I use and auto center punch to get a dimple to hold the bit then start with a small hole and go up from there as needed. I used a 5" bi metal hole saw for my extra speakers, came out really nice after a quick clean up with some sandpaper inside and out.

I find for screw holes you need a bigger hole than in wood, the glass does not give much to allow for the threads to bite in.

 

[ruztew]

I just went through the same thing, thought the Polk speakers would be a super quick replacement, they weren't... ended up drilling new holes.. just make sure your use the right side bit, too small you'll crack and screw won't go in. Also, on mine, the terminals were different sizes, you'll either need to cut the old ones off or use some pliers and crush the terminals down to get then to seat well on the Polks

 

[OperationROL]

Hello Members,

I would post in the electronics forum but I feel this can be used for more scenarios. I purchased new speakers to replace the papers ones. I thought the Polk DB510 would be simple drop-ins and I guess they are. The fit in the holes but the screw holes do not line up. Any tips on how to drill through the fiberglass and gelcoat? Im a bit handy but kind of terrified of cracking a big piece and messing my beauty up. Tips?

Your boat came with 5 1/4 speakers? I thought all the 24 footers came with 6 1/2 's.

 

[njmr2fan]

Much smaller hole, but anyway... I found a stepped drill bit made a super clean hole. When i was installing the SIMRAD this weekend I had to drill a 1" hole, I taped it, used a stepped drill bit and the hole was clean.