Sealing screw holes in fiberglass, and starting new holes

[Pseudomind]

Look above the USA flag in my avatar you will see a beige looking object. This is a tan colored drink holder which swivels on a gimbal. I want to replace. This beige one has two screws which are about 1/2 inch apart screwed into the fiberglass. The new replacement holders are white and have two mounting holes about one inch apart.

I wish to remove the old and seal the holes with something. There will be no need for sanding as the new cup holder mounts will conceal these older holes. I just do not want to leave any open holes for water to somehow finds it way into. Do I need something like (I believe it is called 5200 or 5250) to put into these holes?

To mount the new holders, do I need to first drill a small pilot hole into the fiberglass? I do not wish to put a screw in and then end up with stress fractures showing.

There is a picture of the screw at the link below, the old mount screws 1/2 inch apart, new screws about 1 inch apart, thus the reason for sealing old holes and drilling new holes.

Gimball drink holder

Thanks

:thumbsup:

Thanks

 

[Lazy Daze]

Anything you have laying around will work to fill those holes - silicone, 5200, whatever. Can you re-use one of the holes?

Here's a thread about how to drill into fiberglass without creating cracks in the gel coat:

http://clubsearay.com/forum/showthread.php?t=17850&highlight=screw

 

[Pseudomind]

So if I read this correctly, I need to use a drill bit the same diameter as the screw I am using and to go very slow to keep from cracking the gelcoat? :huh:

Thanks for your comments I am going to reread the thread again as I do not wish to start any spider web cracks on the gelcoat
:thumbsup:

 

[doozie]

I find the best way to start a hole is to drill in revese till you get beyon dthe gel coat layer. Bob

 

[Tonka Boater]

So if I read this correctly, I need to use a drill bit the same diameter as the screw I am using and to go very slow to keep from cracking the gelcoat? :huh:

Thanks for your comments I am going to reread the thread again as I do not wish to start any spider web cracks on the gelcoat
:thumbsup:

I just drilled 2 small holes in my boat. I used a bit the same diameter as the screw and drilled the entire hole in reverse...as slow as possible while still making progress. I also put some silicon in the holes to seal the screws just to be safe.

.

 

[Cincy Aquaholic]

I'm a big fan of using Marine Tex - http://www.marinetex.com/MarineTexproducts.html - to fill a hole but since these are not going to be visible, below the waterline or needed to drill into 5200 should suffice.

Also, when drilling, its best to finish the hole off with a countersink bit to bore the gelcoat away at the top so the screw doesn't crack it when you put it in. Starting the bit in reverse may help but what happens when you screw in the screw is that the gelocoat catches the threads and lifts up and cracks. You need to widen the hole a bit more than you do with the drill to avoid that with this bit.

 

[Pseudomind]

There is a link in the first post. the screw will actually be on the outside of the gimbal mount, so I am guessing any countersink is not necessary.

Again thanks for all input so far:thumbsup:

 

[Lazy Daze]

There is a link in the first post. the screw will actually be on the outside of the gimbal mount, so I am guessing any countersink is not necessary.

Again thanks for all input so far:thumbsup:

The idea of the countersink is so that NO screw threads contact gel coat. Remember to use a drill bit a hair larger than the screw shank. Fiberglass does not compress as much as wood.