US Composite Epoxy Curing Question

T

Tom Riegel

Member
Had to redo the bottom of my Hummer layout this winter due to moisture and laminate separation. Started the fiberglass layout this past weekend using US Composite's 3-1 resin/hardener. I used it in the past and had 0 problems. Well, it setup withing 36 hours but had a slick sticky film on top. It's cooler now and my garage is staying between 50 60 F so I figured it was just taking a little longer to finish. Well its been a week and the film is still there. Has anyone else run into this problem before and what did you do to correct it. I'm thinking about taking my heat gun and setting it on its lowest setting and running it over i, making quick passes just to see if that helps.
 
I recently had an issue with my Widgeon Refurbish. http://www.duckboats.net/cgi-bin/forum/gforum.cgi?post=273539;search_string=epoxy;#273539 Post #24 starts the conversation.


I ended up using a heat lamp and actually "cooking" the resin. I put the heat lamp on a small section for several hours to cure it, then moved it to another small section and so on. Took some time, but worked.


I mixed and used it after this episode, without any problems, so I guess it was me?


Jon
 
Slight film could be blush, which tends to be worst with high humidity cure (I don't know about the effect of slow cure on blush). US composites is not known for a lot of blush. Does you fingernail dent the epoxy, can you dig into it with a tool? If it a very thin film and it is blush, it will wash right off with water on a rag.
 
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I used US composites some years ago and got blush as well. I cleaned it off with the apropriate liquid. I can't remember what. Also 50-60 degrees is pretty cold for epoxy. I had to use the 'hot' fast curing mix in cooler weather.

If you heat it up after it is applied, hidden air pockets can expand and create horiffic bubbles in the finish. That is what happened to me.
 
I seal all my decoys with US composites but I use the 1:1 mixture. Have never had a problem. However another carver I know has been using the 3:1 mix and has yet to get a good finish. He has even went so far as to weight each component to ensure a correct mix. Still gets the cloudy look and never really seems to cure, stays tacky. He switched to what I use and no problems,..... it may be that particular mixture. Depending on the size of the project and how you really want the finish to look, I would sand and start over with a new batch of epoxy.
 
Ok, well all of these answers make since. I live on the coast of NC and humidity here rarely falls below 50%. In fact, I ran a dehumidifier in the garage before and during the application just to get it down but never got it below 55%. As far as the temp in the garage I tried running an electric heater in the garage but its just not enough to raise the temp high enough. I can't dent the finish with my finger nail so I know it's hard enough so it must just be blush. I do have the pumps for measuring but even before I used them I did a measurement to make sure that they were correct and they were. I could also tell that once mixing the epoxy that my mixing cups were heating up so I knew that the hardener was doing what it was suppose to do. i guess its as mentioned "blush". Thanks Folks!
 
That was the problem. A rag, towel, hot water and a lil elbow grease did the job. Thanks Tod! i have just finished up lightly sandng with 80 grit and wiped her down. Just giving it a lil while for everything to settle and then I'll give her another wipe down with a tack cloth and I'll be on to putting another coat of epoxy on. Thanks Again all!
 
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