First gel coat repair attempt = not good

Yesterday I used a one part white gel coat from West Marine (Evercoat) and mixed it with a coloring agent. I applied it to the hull, smoothed it out then covered it with wax paper to keep out the air. This morning I removed the wax paper and the get coat had not set up.

Any thoughts? Looks like I may be sanding this stuff off.

Gel coat
Put some white vinegar in a spray bottle and spray the gel coat. It should help it set.

Foggy memory but…

– Last Updated: Mar-07-11 10:05 AM EST –

The last time I did gel coat repair, I seem to remember that I used white gel coat and added a drop or two of some kind of hardening agent. I also covered it with something unable to react with it, I think it was plastic wrap.

I recall that it was easy to overshoot the hardener.

see if this helps

needs exposure to air?
I would think if it doesn’t use mekp as a catalyst then it would need exposure to air to cure.

Two things
a) You need a catalyst to make the resin harden. About 1 to 1.5% (by volume) MEKP works very well

b) Even with the hardener, you still need to seal it from oxygen. Most people use polyvinyl alcohol (PVA) which you can spray on with a mister. It is water soluble and washes off easily after the gel coat kicks.

Many gel coat repair products have built in agents for flattening, sealing, etc. Personally, I find that keeping the chemistry simple and using a little elbow grease to sand the final coat works best.

Give it time
If it’s finish gel coat I don’t believe you have to cover it. Did you mix in the hardener that comes with the gel coat? I used the same gel coat last year and it took a little longer to harden since the air temp in my garage was on the cool side.

from west marine
you can get “waxed” or “no wax” gel coat.

with the waxed you do not need to cover from the air but you do need to sand if you want to add more gel coat.

with the “no wax” you need to use PVA or some other means of blocking from the air.

Did you remember to ass hardener?

it needs the mekp catalyst …
… if you didn’t add the hardner after tinting (what is a one part gelcoat ??) … just remove it (acetone , wood/plastic scraper , rags) and do it agian following the Evercoat sched. .

Do not cover the gelcoat , you can thin it to help it self level some and fair out easier (tint , catalyze , thin in that order) . Watch the temps. , personally I think 60F. is too cold . At 90F. you can be fairing it (Evercaot) in prep for 2nd coat in 10 mins.

Thanks for the input
Here is what I used:

Maybe this stuff is not for larger areas? I did an area at the stern of about 2" x 2".

I originally bought the stuff that needed hardner. But when I was concerned about mixing the proper ratios the West Marine store owner suggested the one part stuff.

Hi Clarion … The is NO
" one part stuff "

Call me if you want real word advise on this stuff.

I’m going to take you up on that Pat


oh that stuff …
… I’ve never used it , have heard it’s fickle about setting up and has a very short shelf life … maybe your stuff was too old , maybe the stuff is junk ?? In any case I don’t understand how it works , what makes it work ??

scrape with spreader?
In the link to the product info the instructions say to fill the reapir area, let it set, and then scrape off the excess… with a plastic spreader!

Maybe it’s not designed to set hard like real gelcoat, which you certainly can’t scrape off with a putty knife.

Standing corrected but with PW on this.
I did not know of this product but still curious as to how its gonna work.

yea I’m starting to suspect you’re right

I’m not happy with my local West Marine right now. I have a feeling I’m going to have to get this crap off of there. That should be fun.

a few things
It is most likely oxygen activated - basically no oxygen gets to it when the paste is the tube, it kicks off when exposed to air. Similar to countless sealants.

Your wax paper might have detrimental effect on setup time. You also need to be mindful of the temperature - cold is long.

As they said - expiry date might’ve passed.

An easy check - look at tools you used to spread the gelcoat. If it hardened at all, you might be able to wait some more and have decent results.

Otherwise - scrape, clean, and apply some finishing gelcoat.

Having the tube in my hand I would
mix it with some catylist to see if it goes off.

Urethane does not require MEKP

All you guys have to do is use the link to the MSDS, and read it. Since it is indeed 1-part, it is most likely moisture-activated. Allow it to be exposed to the open air, and maybe spritz it with a mister for added moisture.

And keep the catylists away from the repair!


good catch!
Spit and polish, then :wink: