how soon to antifoul over epoxy

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homer

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I have just epoxied the hull (Jotun antipest) and need to know how long I have to wait before antifouling. The data sheet is unhelpful as it only gives overcoating times for more epoxy. The epoxy will be dry in 10 hours or so but needs a week to "cure" so the question is, will it continue to cure with antifoul on top of it? Any assistance much appreciated!
 
The data sheet only gives min/max times to overcoat - it doesn't specify overcoating with more epoxy. So I'd consider you can apply antifouling within the overcoating times shown.

I'd be more worried about current temperatures, as it shouldn't be used below 10 degreesC.
 
I used Gelshield so not quite the same. However with that you either have to put on the first coat of antifoul while the final coat of the Gelshield is still a bit tacky to the touch or wait until fully dry in which case you must use an antifoul primer (don't ask me how I know!!!!!!!!)
 
I think the question should be- is how LATE can I leave leave it before overcoating?.

Epoxy is great at sticking to things; it is less good at having things stuck to it. It needs to be overcoated whilst the surface is still chemically active. Basically, this means as soon as it dry to the touch. Temperature dependant. I would hazard a guess of no more than 24 hours. Any longer than that and you will have to do a lot of abrading.

If you leave it too long, the antifoul will have poor adhesion and start to peel (how do I know this?.........).
 
pvb said:
The data sheet only gives min/max times to overcoat - it doesn't specify overcoating with more epoxy. So I'd consider you can apply antifouling within the overcoating times shown.
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I would also assume that those times apply!
 
PCUK said:
First coat of antifouling is applied as soon as the last coat of Anti-pest is tacky. This acts a as tie coat so that subsequent coats can be applied at any time after.
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Yes this is what I read when I did my hull. If the epoxy has passed this time then ( I understand ) You should check for 'Amine blush' ( ?) and also abrade the surface a bit to help 'mechanical adhesion'.
 
Should therevnot be an intermidiate coating thatseals the expxy an allows further coatings of non epoxy paint such as antifoul......well thats what I did
 
Wansworth said:
Should therevnot be an intermidiate coating thatseals the expxy an allows further coatings of non epoxy paint such as antifoul......well thats what I did
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Depends what the relevant data sheets say. If the data sheets for the products you used specified an additional barrier coat or primer then that would have been correct for those coatings.
It is not required for International antifouling over Gelshield 200 ... It does not appear to be specified for other coatings over Jotun Anti Pest ... Cannot say about others without reading the data sheets.
 
pvb said:
The data sheet only gives min/max times to overcoat - it doesn't specify overcoating with more epoxy. So I'd consider you can apply antifouling within the overcoating times shown.

I'd be more worried about current temperatures, as it shouldn't be used below 10 degreesC.
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Temperature not really a problem here in Almerimar! Thanks for all responses.
 
When I did mine (in winter using Jotun epoxy with low temp. additive) their advice was to use a tie coat of Vinylester 88, But I applied it the same day as the last coat of epoxy. I left the antifouling until the next week.
Jotun Vinylester 88 is a great primer for nearly anything, I used the surplus to paint the cradle, great rust protection and I have successfully used it as a primer on external timber.
 
When I Gelshielded my hull I did as others have said, applied the antifouling while the epoxy was still tacky. The instructions specified that hard scrubbable antifouling be applied, not eroding, as a tie coat/primer. Subsequent coats could be (and were in my case) eroding type.
 
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