Epoxy Drying Time

[FarmallM]

I'm putting a new deck in my '91 Lund 1800. I dried the exterior grade ply in my basement several months last winter. I mixed the epoxy in the proper ratio using a graduated container and rolled it on the ply, even raising the room temp to 80 degrees with an electric space heater. A week later I can still feel a slight tackiness when running my hand over the ply. If I use a paper towel to wipe it down I can see a bit of residue on the towel. Is this normal? Will the carpet adhesive stick to this slightly tacky ply? Thanks.
Marlin

 

[Woodonglass]

Re: Epoxy Drying Time

What kind of Epoxy? How Old was it?

 

[BWT]

Re: Epoxy Drying Time

Unlike some resins (poly or vinyl) epoxy should not remain tacky after cure. Couple of things I would look at is 1) are you certain that the mix ratio was correct (different hardeners within the same brand mix at different ratio's), 2) temperature during cure time, and the big one like WOG mentions is how 3) old is the stuff? Some manufacturers claim that their epoxy is good for many years (even with freeze and thaw cycles) however my experience has told me different.. If the epoxy has not cured I would not bother laying anything else on top of it.

 

[FarmallM]

Re: Epoxy Drying Time

What kind of Epoxy? How Old was it?

It's 3:1 from USComposites and was fresh this spring (kept in my heated basement). I mixed 12oz of resin with 4oz of hardner. The manufacturer's FAQ says that curing time may be extended if a thin layer is used, but I thought 7 days should be sufficient. I can hit it with 100 grit sandpaper in a block sander and hardly leave a scratch, but the grit does tend to fill up with the tacky stuff that's coming to the surface.
Marlin

 

[Woodonglass]

Re: Epoxy Drying Time

I'd call tech support @ UsComposites. It sounds like you did everything correctly. I'm not sure what the problem is here.

 

[FarmallM]

Re: Epoxy Drying Time

I'd call tech support @ UsComposites. It sounds like you did everything correctly. I'm not sure what the problem is here.

I called USComposites and they have good customer/tech service. Called me back promptly. It seems I did everything wrong. He said to add the hardener to the container first, swirl it around to coat the sides of the container, add the resin, stir 6 minutes without lifting mixer or introducing air to the mixture. He said I'd have to remove what I had applied and re-coat it properly. I seem to have missed all these important steps in my research. Oh, well. Live & Learn.
Marlin

 

[BWT]

Re: Epoxy Drying Time

huh, I don't think that I've ever had to follow such strict procedures for mixing; I don't know how the cost of your epoxy compares to West System, but working with WS is like making chocolate milk (throw one into the other and mix it for a minute or two. Never had any problems... BUT, good to hear that their CS is there when you need them! Hope it all works out. For removing the original layup try using either acetone or denatured alcohol after scraping up as much as you can.. Final cleanup with acetone.

 

[MichaelP]

Re: Epoxy Drying Time

Well this was helpful cuz I didn't know that either but I also don't understand. I figured if its mixed well that's it. Got a 2 gallon kit due tomorrow. Thanks!

 

[Woodonglass]

Re: Epoxy Drying Time

Xylene is a MUCH better option for cleaning and dissolving epoxy. Nasty stuff though so PLEASE use a respirator if you decide to use it. I too, am a bit perplexed with their description. I've used their product in the past and did NOT mix in that described manner and did NOT have that issue. This is just me talking here, but I suspect you might have some OLD resin and hardener. I'd mix a small test batch EXACTLY as they described and test it. If it works GREAT. If not, call them back and see what they say.

 

[proshine43]

Re: Epoxy Drying Time

Ive used there epoxy as well and never had a problem...
.

 

[FarmallM]

Re: Epoxy Drying Time

I didn't think of xylene. I'll get some from the histo lab and give it a try because the acetone didn't touch it. I did have good luck using a carbide-tipped scraper. The test batch sounds like a good idea before I commit to the whole project again.

 

[FarmallM]

Re: Epoxy Drying Time

I called USComposites and they have good customer/tech service. Called me back promptly. It seems I did everything wrong. He said to add the hardener to the container first, swirl it around to coat the sides of the container, add the resin, stir 6 minutes without lifting mixer or introducing air to the mixture. He said I'd have to remove what I had applied and re-coat it properly. I seem to have missed all these important steps in my research. Oh, well. Live & Learn.
Marlin

I mixed a small batch and coated some of the smaller pieces using their procedure. I still had some tackiness after 36 hours. I then put an electric space heater in my shop with a circulating fan. I heated the shop (including wood & epoxy components) to 80 degrees F and mixed a larger batch of epoxy for the remaining pieces. This worked much better. It was drier in 6 hours than the small batch was in 48.