Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Polyester resin did not cure correctly
Posted by bcoastal on 05/21/13 - 8:30 AM
#1
I did a layer of poyester over marine plywood to waterproof it last night. Not sure what happened but there are parts of the mix that did not cure correctly...
Anyways should I remove the wet sticky areas? Acetone, sand or should I do another layer over the sticky stuff? It is not structural. Only to waterproof the wood.
Posted by CES on 05/21/13 - 8:51 AM
#2
Hmmmm, seems like you may not have used enough hardener. I'd put it in the sun and let it cure a while longer.
Posted by todd12 on 05/21/13 - 9:43 AM
#3
I agree with CES. Give it a couple of days. I think you would be ok putting another layer over it since its not structural.
Edited by todd12 on 05/21/13 - 9:47 AM
Posted by bcoastal on 05/21/13 - 10:03 AM
#4
Ok thanks.
Posted by Petrus on 05/21/13 - 11:14 AM
#5
If only parts of it didn't cure you migh not have mixed it enough. If it hasn't cured in a couple of days I would have removed the uncured areas before I put new on.
Posted by John Fyke on 05/21/13 - 4:11 PM
#6
Petrus wrote:
If only parts of it didn't cure you migh not have mixed it enough. If it hasn't cured in a couple of days I would have removed the uncured areas before I put new on.
Exactly. Not mixed enough..
Posted by cwk6 on 05/21/13 - 4:39 PM
#7
I might try some cautious use of a heat gun to warm areas that have the cured yet. Then give it a couple day.
Posted by wing15601 on 05/21/13 - 4:40 PM
#8
When you say sticky, do you mean it is the same as when applied or has it partly cured? If it is partly cured you should give it some time as the process will continue. I notice you are in Texas so adding heat won't help. I would give it a week before trying to scrape off any uncured resin. I'm not sure if polyester resin produces amine blush, you can investigate that, and if it does you will have to remove any blush by washing with water then sanding prior to recoat. the thing about resins is the thinner you spread the resin the longer it takes to cure. if you leave a volume of resin in a paper cup it can produce enough heat to actually catch on fire but if you spread it in a thin layer it has a harder time generating heat.
Posted by bcoastal on 05/21/13 - 5:52 PM
#9
It was only tacky in some areas making me think I did not mix well. I went ahead an removed as much as I could with acetone then sanded the stickyness away. I will apply another coat tomorrow. This time before I throw back a few cold ones. Thanks for the replies
Posted by sammidog on 05/22/13 - 12:04 PM
#10
In the future you may consider epoxy rather than polyester. It will stick much better to wood than the polyester.
Posted by ritzyrags on 05/22/13 - 1:00 PM
#11
You will be wise in getting a new vial of MEK and to add about ten to twelve drops per ounce to the polyester resin.
Make sure that the resin is not too dated and mix in a cup.
Two to three hundred turn of the tongue depressor without forgetting to scrape the sides and bottom thoroughly while doing this important step; will guarantee you a final good mix.
Having done and verified all these important steps will send your resurfacing detail in the direction of a good sailing.:)
Edited by ritzyrags on 05/22/13 - 1:02 PM
Posted by CES on 05/22/13 - 1:03 PM
#12
sammidog wrote:
In the future you may consider epoxy rather than polyester. It will stick much better to wood than the polyester.
I agree.....it's worth the extra few $$