polyester resin hull repairs

[roger2009]

I have just carried out an osmosis repair to my hull using polyester resin and faired the hull with polyester resin with filler powder added.I was advised by a professional boat builder that this would be ok as long as I then treated the hull with an epoxy protection system.
Has anyone carried out this procedure and if so, do you need to have a time delay between the repair and the protection treatment to allow the polyester to fully cure.
Advice would be greatly appreciated.

 

[oldsaltoz]

A couple of days above 20*C should be fine.

Make sure the area to be treated is wax free, wash down with Acetone.

FWIW, I would only use an epoxy resin to carry out repairs below the water line.

Avagoodweekend......

 

[lw395]

I suspect the recommended time might be longer, maybe worth asking the manufacturer? Try international.
Most yachts are built of polyester, I would use it for repairs that want a lot of resin, but I would have used epoxy for the fine filling. Its a matter of cost vs extra performance.

 

[tri39]

Ideally an epoxy coat should go on the polyester glass/resin rather than the filler. But no doubt an epoxy layer now will still improve the waterproofing. I'm fairly sure you can press ahead if it's warm and dry.

 

[William_H]

Polyester has some shrinkage more than epoxy when it cures and doesn't seem to have the adhesion ability of epoxy. However in boat manufacture this is no problem as in curing polyester sticks to itself very well to form an integral hull. Polyester does not however stick to cured polyester as well as epoxy. I am not saying it will fall off but there is no chemical bond so it is only the physical grip that holds the repair in place. Hence epoxy is better even though the original is polyester.

certainly polyester is hopeless on wood compared to epoxy but of course wood is much more difficult than cured polyester to stick to being water absorbant and more flexble.
So having got so far as said clean the polyester repair and coat with epoxy. olewill