Fibreglass of gel coat along deck joint?

[Andy Kirkpatrick]

Hi. I want to add three layers of glass to my hull/deck joint, to keep out the water (old Hurley 22). I know I’m supposed to grind off the gel coat, but it seems a bit unnecessary. Would it be OK to just roughen up the gel coat (40 grit), and fibreglass over it (with epoxy).

Thanks

Andy

 

[Hacker]

No, it won’t bond.

 

[Andy Kirkpatrick]

No, it won’t bond.

Roger that.

 

[DFL1010]

Hi. I want to add three layers of glass to my hull/deck joint, to keep out the water (old Hurley 22). I know I’m supposed to grind off the gel coat, but it seems a bit unnecessary. Would it be OK to just roughen up the gel coat (40 grit), and fibreglass over it (with epoxy).

Thanks

Andy

Not sure if you've come across the site yet, but West Systems have a load of guides and whatnot on their site:
Instruction | WEST SYSTEM Epoxy

They also wrote a fairly comprehensive book on the subject:
https://www.westsystem.com/app/uploads/2024/08/GougeonBook-08.2024.pdf


Understandably written with the West products in mind, but the principles will apply for other products (some modifications to technique may be required in some situations).

 

[William_H]

Yes of couyrse it will bond provided gel coat is clean and roughened. Just how well and for how long is debatable but I reckon it will be ok for your purposes. I can not however imagine how fibre glass will be necessary. I just think a coat of paint might fix your leaks. Unless there is real movement of the joint. ol'will

 

[Refueler]

Unusual for hull joint to leak unless boat has had a bang or event to cause it .....

Are you sure its a leak ? Could it be condensation collecting and running down ? Could it be from a fitting nearby and water is running the deckhead and then down hull side ?

 

[Ceirwan]

It depends on the construction style.

If the joint is not moving, then I've had luck with running a bead of thickened epoxy on the inside of the joint where the arrow shows. I then used a wooden mixing stick to give it a nice fillet.


On that boat, they'd used a neoprene gasket and in a couple of places it was leaking.
Taking the entire toe rail off without destroying it was going to be nigh on impossible. It lasted for the 6 years I had the boat.

 

[Jodel]

If by 'fibreglass you mean chopped strand mat (CSM) then it will not work with epoxy due to the coating on the glass. Either use CSM and polyester resin or woven glass cloth and epoxy.