Repairing fibreglass

[Humblebee]

Hi there. I've just bought a small trailer sailer which has been rammed and is badly holed. Is there anyone in the Aberdeen area who is used to doing fibreglass repairs and would be able to offer me some advice? I have done some work with fibreglass but this is more complex than anything I've done before.
Thanks
Chris Anstock

 

[Guest]

It's not as hard as you may think. Our local supplier of epoxy resins and glass has a book about how to do repairs to fibreglass. West System also have a very affordable guide on how to repair boats using epoxy products although the infoprmation can be applied to an epoxy products. I use epoxy for this as it sticks very well to polyester and as I am a slow worker in no rush the long gel times suits me.

I had to fix three 4 X 10 inch holes on my boat a while ago after an argument with a coral reef. I simply ground out all the de-laminated glass into a nice shape and then ground back the edges about 2-3 inches like a scarfing joint. I made some flat pieces of fibreglass a little bigger than the holes which could be epoxied onto the inside of the hole to support the new glass.

Prime all the surfaces with epoxy then layer on new glass with the first layer covering the whole area then progressively getting smaller as the thickness builds up. Use a small roller to squeeze the epoxy into the glass and to remove excess. As epoxy doesn't set for ages you should be able to do the whole repair in one hit. Let it set then flatten it with the sander again. The results have been perfect with many more miles and no sign of leaks or de-lamination.

 

[Guest]

Hi , Please be careful!!! your previous respondent has suggested the use of epoxy resins in the repair of your craft for the slowness of curing. I was taught and some experience confirmed that epoxy and polyester do not mix that is the epoxy resin does not adhere properly to the polyester or maybe vinylester which was probably used in the construction of your boat. having spent some years doing mainly repairs at a boat yard I can say that never were unlike resins used in the repair of glass boats by that yard. As to the rest of his info it appears good and the surveyors in this country reccommendthe 'feathering back of the holes to be 20 times the thickness of the hull to enable a good take of the repair.All the best
B

 

[Guest]

I agree on the 20 times feathring but not so much about the unlike resins. Goughen Bros (West) and others have done a lot of testing on epoxy resins. They have found that epoxy will stick to already hardened polyester resins just as well as polyester and in itself is stronger. The other way around does not apply ie wet polyester does NOT stick to hardened epoxy very well at all so you are right you shouldn't mix resin types especially if the boat is made out of epoxy (which I am sure the trailer sailer isn't). The advantage of epoxy is the whole repair can be done at once and not in little stages so there is no need to key in layers of glass to each other as it is all done pre-hardening. Epoxy is also more expensive which may be an issue. I have used epoxy patches on all manner of polyester things from canoes and surfboards to several of my anf friends yachts with never a hint of failure to any of them.

Epoxy is just so much easier to use!

Cheers