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Polyurethane and tacky epoxy
Has anyone tried or know what would happen if you applied a
polyurethane product over epoxy when the epoxy was still tacky. Would the adhesion be better? Would it intefere with the cure of the epoxy? What about a latex primer over sticky epoxy? Anyone try anything like that to try and get a better adhesion to the epoxy? TIA, Bob |
Polyurethane and tacky epoxy
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Polyurethane and tacky epoxy
On Jun 23, 6:26 pm, Lodewijk Stegman
wrote: schreef in news:1182605034.890782.50700 @m36g2000hse.googlegroups.com Has anyone tried or know what would happen if you applied a polyurethane product over epoxy when the epoxy was still tacky. Would the adhesion be better? Would it intefere with the cure of the epoxy? What about a latex primer over sticky epoxy? Anyone try anything like that to try and get a better adhesion to the epoxy? I have never tried it, for the reason that my local vendor warns against doing this. They even claim that is wise not to paint epoxy before it is fully (and I mean FULLY) cured. That can take up to a week, depending on temperature and formulation of the epoxy. Adding another coat, before the previous coat is not fully cured, works great for the adhesion between coats of epoxy, but not between epoxy and something else. -- Lodewijk I laid some marine enamel down once on tacky epoxy, forget the brand, but it made a great bond. But note it was pure luck because in other attempts to do this in uncontrolled environment led to major peeling. I think the best way to go is "traditional", washing the surface, roughing it up, and depending on a mechanical bond. Just my opinion. |
Polyurethane and tacky epoxy
wrote:
On Jun 23, 6:26 pm, Lodewijk Stegman wrote: schreef in news:1182605034.890782.50700 Has anyone tried or know what would happen if you applied a polyurethane product over epoxy when the epoxy was still tacky. Would the adhesion be better? Would it intefere with the cure of the epoxy? What about a latex primer over sticky epoxy? Anyone try anything like that to try and get a better adhesion to the epoxy? I have never tried it, for the reason that my local vendor warns against doing this. They even claim that is wise not to paint epoxy before it is fully (and I mean FULLY) cured. That can take up to a week, depending on temperature and formulation of the epoxy. ------------------- We have put wet latex over wet epoxy (epoxy that was mixed minutes before). If it is a top epoxy you get a perfect finish, of course you cannot brush the latex paint on.... folks usually wait a bit past tacky (but still soft enough to put your thumbnail into the epoxy). Actually epoxies take about a week to fully cure, so if you have topcoated epoxy in less than a week, you've actually painted over not fully cured epoxy anyway. At least in theory, the coating fuse and you get a chemical as well as a mechanical bond. paul oman progressive epoxy polymers inc www.epoxyproducts.com/marine.html |
Polyurethane and tacky epoxy
Paul Oman wrote:
We have put wet latex over wet epoxy (epoxy that was mixed minutes before). If it is a top epoxy you get a perfect finish, of course you cannot brush the latex paint on.... folks usually wait a bit past tacky (but still soft enough to put your thumbnail into the epoxy). Actually epoxies take about a week to fully cure, so if you have topcoated epoxy in less than a week, you've actually painted over not fully cured epoxy anyway. At least in theory, the coating fuse and you get a chemical as well as a mechanical bond. provided, of course, that no surface blush has developed... |
Polyurethane and tacky epoxy
cavelamb himself wrote:
Paul Oman wrote: We have put wet latex over wet epoxy (epoxy that was mixed minutes before). If it is a top epoxy you get a perfect finish, of course you cannot brush the latex paint on.... folks usually wait a bit past tacky (but still soft enough to put your thumbnail into the epoxy). Actually epoxies take about a week to fully cure, so if you have topcoated epoxy in less than a week, you've actually painted over not fully cured epoxy anyway. At least in theory, the coating fuse and you get a chemical as well as a mechanical bond. provided, of course, that no surface blush has developed... --- that's true, but the good epoxies generally don't blush --- paul |
Polyurethane and tacky epoxy
On Jun 23, 8:23 am, wrote:
Has anyone tried or know what would happen if you applied a polyurethane product over epoxy when the epoxy was still tacky. Would the adhesion be better? Would it intefere with the cure of the epoxy? What about a latex primer over sticky epoxy? Anyone try anything like that to try and get a better adhesion to the epoxy? TIA, Bob Thanks guys. I guess I'll let it cure first. I was hoping to avoid sanding because the sanding won't be the easiest. It's nott a nice flat surface. It's all fillet sanding and the fillets aren't the smoothest.. |
Polyurethane and tacky epoxy
On Jun 28, 7:49 am, wrote:
On Jun 23, 8:23 am, wrote: Has anyone tried or know what would happen if you applied a polyurethane product over epoxy when the epoxy was still tacky. Would the adhesion be better? Would it intefere with the cure of the epoxy? What about a latex primer over sticky epoxy? Anyone try anything like that to try and get a better adhesion to the epoxy? TIA, Bob Thanks guys. I guess I'll let it cure first. I was hoping to avoid sanding because the sanding won't be the easiest. It's nott a nice flat surface. It's all fillet sanding and the fillets aren't the smoothest.. One thing I have found you can do is scrape nearly cured epoxy with a dutch scraper, or even a wood rasp if you need to take down more material. Of course, if you are painting opaque, you can use a fairing compound to fill in areas which makes for easier sanding. Good luck, keep the elbow brace handy... |
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