Gelcoat Questions

[Hauger]

Hi...

I have a 20' bowrider that for some reason had only one cleat on the port side of the boat. I figured I'd like to have a second there, so I installed one yesterday by drilling through the gelcoat/fiberglass, putting some 3M 5200 in the holes and on the threads of the bolts, then bolting to a metal backplate.

The results look good.

Then I got to thinking. Should I have Chamfered the holes? I would say the bolts are touching the gelcoat right now. Does the possibility of cracking the gelcoat come from the actual screwing in of the bolts, or does it come later when the boat's being flexed in the water an the gelcoat's moving against the bolts.

I guess the question is, should I remove the cleat, chamfer the holes, then re-install? It's a pain to do, but I'd rather do it than risk a bunch of cracks in the gelcoat later.

Thanks.

 

[Bondo]

Re: Gelcoat Questions

Ayuh,.... I don't see any reason to do it again...

 

[Hauger]

Re: Gelcoat Questions

So......that's a "yes, go and chamfer the holes", or "no, if it went on fine, just leave the screws in place"?

 

[Philster]

Re: Gelcoat Questions

Leave as is. Move to next project.

 

[Hauger]

Re: Gelcoat Questions

Sold. I'm looking at it now and everything looks good. That, and the 5200 is set now, probably cause more grief to try and fix it now.

Thanks for the reply.

Now onto next job, "fixing" the speedometer.

 

[sasto]

Re: Gelcoat Questions

Common practice has been to chamfer/countersink all pilot holes for self tapping screws because the screw itself is larger than the hole and gelcoat is a brittle substance that will crack under the strain.

 

[Hauger]

Re: Gelcoat Questions

See, maybe that was my saving grace...I drilled the holes to be snug, but slightly larger than the bolts, then used washers/nuts/backer plate to pull it tight, instead of letting the threads bite into the fiberglass.

So I take it I don't really have to worry about the gelcoat spidering from this install then, even though I didn't chamfer the holes.

Thanks again for the replies.

 

[oops!]

Re: Gelcoat Questions

no...you dont have to worry.

the gellcoat crazes if there is stress on the area, if it is under or over catylised

but crazing from a thru hull....no.

i install wake towers all the time and i dont chamfer the holes

go enjoy your boat...
but come back here to visit from time to time...lol