How long before painting over epoxy?

Fantasie 19

Fantasie 19

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Just finishing up a couple of replacement hatches which being ply I've epoxied over .. how long do I leave them before painting, and can I just paint straight over with a primer??

I wondered about using car spray paint - any issue with that?? :confused:
 
When it is fully cured and the amine blush (if any) is removed. You may need a bit of abrading to provide a key for the primer.
 
Amine blush is like a cloudy residue on the surface.
Some paints react to some epoxies quite a while after they've been applied. Weeks at least.
AIUI some 'traditional' yacht varnishes are the worst. I have been caught by this.
I've used acrylic car spray paint on dinghy rudders after letting the repair harden in a warm room for 24 hrs with no problem if that helps.
I think that was West System epoxy and paint from Halfords.
 
Fully cured time will depend on which epoxy you used, the accuracy of your mix and the temperature and humidity. That is why i did not suggest a time. However, for your sort of job it is not critical you paint will get a mechanical not chemical key. So, provided it is hard and will take a light abrasion you should be OK. Make sure you wash the surface well before applying the primer.
 
Fantasie 19 said:
Yep - but that's the point of my question - how long typically before fully cured?? Also - I have heard of it - but how would you know what the dreaded blush looks like?
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Curing time should be calculable from the information which came with epoxy. No-one on here can answer your question without knowing exactly what it is and the ambient conditions since mixed.

Amine blush isn't always easy to identify visually, although as LW395 wrote, it often shows a cloudy bloom. The usual quick test is with litmus paper (amine blush is alkaline). But you have no need for anything fancy: just assume it has the blush and wash it with soap and warm water -- it can do no harm. When dry, abrade lightly but thoroughly, clean again, then paint.
 
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macd said:
Curing time should be calculable from the information which came with epoxy. No-one on here can answer your question without knowing exactly what it is and the ambient conditions since mixed.

Amine blush isn't always easy to identify visually, although as LW395 wrote, it often shows a cloudy bloom. The usual quick test is with litmus paper (amine blush is alkaline). But you have no need for anything fancy: just assume it has the blush and wash it with soap and warm water -- it can do no harm. When dry, abrade lightly but thoroughly, clean again, then paint.
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Cheers guys.. West System 105 and 205 mixed as per instructions (5:1).. no cloudy bloom... will wash, abraid and spray with car paint... :encouragement:
 
Reply I received from International Paints re: varnishing over epoxy:

I would suggest you leave the West System to post-cure for at least 2 weeks prior to over coating with Compass. As fresh West System will affect the drying of Compass. We would recommend prior to over coating with Compass that the West System is thoroughly washed down with water & detergent and abraded.

J
 
ningcompoop said:
Reply I received from International Paints re: varnishing over epoxy:

I would suggest you leave the West System to post-cure for at least 2 weeks prior to over coating with Compass. As fresh West System will affect the drying of Compass. We would recommend prior to over coating with Compass that the West System is thoroughly washed down with water & detergent and abraded.

J
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Ta for that... can't wait two weeks, but I'll leave it to next week before I paint..
 
I thought that when I epoxied my hull I was recommended to use the paint when tacky technique for the primer as well as for each epoxy coat, it certainly worked for me!
Too late for the OP of course so mechanical adhesion will be required.
 
pcatterall said:
I thought that when I epoxied my hull I was recommended to use the paint when tacky technique for the primer as well as for each epoxy coat, it certainly worked for me!
Too late for the OP of course so mechanical adhesion will be required.
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Not all epoxies are the same and application of epoxy sealing coats on hulls is very different from using neat laminating and coating epoxy on wood. As ever follow the instructions and as you can see in this application they are very different from hull coating.
 
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