Vinylester fairing / Gelcoat over Epoxy Based Repair

[ktm_2000]

Hi folks,

In my project I've been doing most of my structural below deck repairs with epoxy resin. Most repairs and work areas are now at a state where there is a solid layer of 1708 set in epoxy. When I do my deck and doghouse I was planning on doing the whole job in vinyl-ester and then fairing out and sealing the deck in gelcoat. I priced out vinyl-ester fairing compound and gelcoat and it is more economical for me to purchase in 5 gallon buckets yet I won't need 5 gallons of either material for my deck and doghouse.


So I am wondering if I could purchase in the 5 gallon increments and am looking to fair out and seal the bilge areas in gelcoat with the excess vinyl-ester resin based materials. Can I go over what I have, or do I need some type of bonding agent? I've seen duratech surfacing primer mentioned to do this function.

I've seen some articles mentioning that the chemical nature of epoxy with the amine based catalyst will prevent the vinyl-ester from curing out. The articles mentioned that if the epoxy was fully cured before applying the vinyl-ester it wouldn't be such an issue. I'm guessing a good cure + duratec would allow the use of the vinylester.

what have others done in the past successfully?

[ktm_2000]

I found this article - looks promising

synopsis, let epoxy cure out, wash with soapy water and scotchbrite to get rid of amine blush, let dry, sand appropriately then the surface should accept vinyl-ester fairing /gelcoat.

https://www.epoxyworks.com/index.php/ap ... ver-epoxy/

[CamB25]

Be mindful of the relatively short shelf life of VE resin.

https://www.fibreglast.com/product/about-resins

[ktm_2000]

Thanks Cam, I did not know that about vinylester resin.

I haven't purchased any of it yet, was planning on making a bank account reducing run to LBI Fiberglass tomorrow morning before work. The one decent thing is that I plan on using the bulk of this material in the next 2 months so it won't matter for most of it.

I was thinking of buying 5 gallons gelcoat using what I needed for the deck and bilge then , doing the inside hull sides as well as topcap repairs next year with the excess. It seems that plan might not be the best way to go so I will get gelcoat in gallon form, I'm thinking the bilge, transom and cabin top would take 3/4 gallon and the deck will take more than one gallon, If I get 2 gallons now, I might run short on the deck and I could get more as needed. At least that is better than having 2+ gallons go bad over the winter and me using it the next year getting bad results requiring a lot of rework.