Tacky epoxy after 24 hours?

Has any one had a problem with the epoxy not "drying" after wetting out the fiberglass?

I wetted out the fiberglass Thursday evening.  I am using MAS resin and MAS slow non-blushing hardner.  I am in Florida, it was about 87 degrees in the garage during the working time.  All things went well during the process, in fact the fiberglass looks great.  However, there is one small section where the epoxy is still tacky.  When you touch you can see small glue "fibers" pulling on the finger.  But right next to it the glass is completely normal and was from the same batch of epoxy.  The section was the first pot, but again other sections from the same pot are normal.

 The garage is getting up to 95 degrees during the day, could that be effecting how it is setting up?  Moving forward what do I do?  Can the next coat of epoxy go over this section if it never sets up? 


7 replies:

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RE: Tacky epoxy after 24 hours?

Did you do a thorough job of mixing the resin and hardener?  Epoxy reps aways say that most problems with epoxy are caused by inadequate mixing.  If it doesn't set up hard, you will need to remove what's on there.

Cheers,  Grant

RE: Tacky epoxy after 24 hours?

The epoxy will dry, but it may take days.  dry up as much as possible and dry out. this will have to be redone.  epoxy when mixed with correct portions, work.  there probably was not the correct proportion or mixing was not adequate.

RE: Tacky epoxy after 24 hours?

Where in FL are you?  You can find me in St. Pete.  And yes I am afraid both are right, it was not mixed up well.  If it was bad ratio then it would effect the whole pot.  Mass down here sets up really fast for me, why I have to mix small amounts.  I can get 3 coats on in a day sometimes.  You can see my blog at www.kayakkev.wordpress.com or email me at kev_th@yahoo.com if you live close enough for me to come help, or have other questions.

RE: Tacky epoxy after 24 hours?

Thanks Kayakkev, I am in Vero Beach other coast.

 I called CLC and they suggested I put the kayak in the sun for a few hours.  There were some bubbles in the area (out gassing?) but it is till tacky- it has now been a week.  The fiberglass is mushy.

How do I repair this small section?  Sand through and make a new fiberglass patch in this section?  What does redoing this entail?


RE: Tacky epoxy after 24 hours?

If it is still soft, then I would try to scrap off as much as you can with a putty knife, mixing some fresh epoxy up and reapply.  If that hardens but the glass shows, then you can sand it down and do a glass patch.

RE: Tacky epoxy after 24 hours?

This is everyone's nightmare scenario. And a really good reason to use proper mixing techniques, scraping sides and bottom of cup and mix for 3 minutes. And if in doubt, DON'T scrape sides of cup when pouring out of the cup and onto project.

Uncured epoxy is sometimes removable with a combination of denatured alcohol, or lacquer thinner, or acetone and heat. I've used a hair dryer to warm it to about 160 degrees F, apply alcohol and rub/scrape to get as much off a I can. You will have to sand back to a properly cured portion to remove the fiberglass cloth that is embedded with uncured epoxy. It all has to come off, right down to the wood so that a new batch will attach and cure properly. IF you put new epoxy down over uncured, it will blister with age.

If this was the first coat of epoxy, the wood has been saturated with a non curing finish and getting anything to stick is going to be problematic. All you can do is heat, wipe, heat, wipe until no more epoxy migrates out of the wood. 

PS. Don't use a heat gun. It will destroy your kayak. 

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