Oquestion about epoxy

[outasite]

I'm using us composits 635 thin epoxy with medium set hardener. My ambient temp with no heat is around 40/45 degrees.My question is,can I set half of my job one day in the 40/45 degree temp,come back the next day and set the rest,bump the heat to 70 and leave it.I don't think the first day's work will kick at 40/45,but will it hurt to let it sit for 24 hrs before giving it enough heat to cure?

[XstreamVking]

The main danger of letting it sit for a long time is drainage of the resin from the glass. I would check the cure chart for the cure rate and minimum temps you can apply it. You need to find the minimum cure temp and keep the shop above that until the resin cures or it may not cure correctly. This is my understanding of epoxy.... Once it is mixed it has to be kept at a certain min. temp till cured.

[W2F a V-King]

At 50-60 degrees I had no real trouble with puddling/drainage on the floor/core area. I did keep check on it with my roller though.

I bet once you start you'll go further than you think.

[LakeFever]

Epoxy and cold dont mix well imo. Better too warm than even a smidge too cold. I was using an epoxy putty coat on a Chevelle restoration when the two part putty was still a relatively new product. The back corner of my shop had a drafty door and a poor seal around the bay which is of course where I had this car parked to work on. I was rushing like mad to get away for a snowmobile vacation so I mixxed up a batch, smoothed over the whole quarter, and left for the weekend. Shop temp was around 60/65 but that dang drafty corner.... When i got back to working on it days later the putty had sort of half cured. It was an absolute nightmare because I couldnt sand it being sticky, and I couldnt remove it with a blade because it was bonded! I tried a lot of things and in the end I used a wire wheel on a die grinder and spent a day gently pealing it all out of there.

Since then? I dont try to mix cold and epoxy ever. I know not all epoxy is the same when it comes to quality and set time and whatnot but those temps seem risky to me....

[W2F a V-King]

Must have been a different kind of epoxy. The type mentioned in this thread will set and cure fine at 50+ degrees. Or mine did anyway. It does give more work time for sure.

[XstreamVking]

Air temps and actual surface temps can vary quite a bit.

[outasite]

Thanks to all for sharing your experience. I think my best bet is to call USC and put together a couple test panels.will post my results in a few days.

[outasite]

Ok,set temp at 55 mixed four ounces laid up a few different combos including one that was put on the floor (cooler). At 2:15 it was still easily wetable,so I left.Came back at five hours and it had started to kick.came back today at twenty four hrs, and had a very good set on all pieces. The quarter inch leftover in the cup shattered when hit with a hammer! I may try once more at 50 degrees. But at least I now have a good idea of working time and confidence it will set. The two scrap pieces of 1708 were on the floor (coldest)I put it in the vice and can hardly bend it

[rjdubiel]

Bob, does this epoxy your using have a blush that comes to the surface once it cures? It would be cool to just sand between layers of glass and go. I have been using peel ply but still a pain to lay it out and get it nice and flat on the glass when wet.

[MattGreen]

Bob, does this epoxy your using have a blush that comes to the surface once it cures? It would be cool to just sand between layers of glass and go. I have been using peel ply but still a pain to lay it out and get it nice and flat on the glass when wet.

Assuming you have done a good job squeegeing the glass out, once you lay on the Peel Ply roll it out again with a bristle roller (not a notched roller - one with firm nylon bristles). Once you yank off the Peel Ply you’ll have a great laminate surface. I love Peel Ply

Matt

[outasite]

It seems there are three things that contribute to blush,cold,humidity,and pooling of resin.Fast cure may also be a factor.I think you can get away with one of the three and not not have a problem,I've never used peel ply but I think it's probably a great tool.So far in my test I have not had any sign of blush.This test board that I'm posting was cured at 55 degrees with way more resin that would normally be required,and as you can see no sign of any blush.Another thing for a finale coat instead of peel ply try some bakers oven paper,it will leave a very nice shiny finish.

[W2F a V-King]

Only time I had blushing with the epoxy I used was puddling of any excess resin in places I missed when cleaning up, which brought the temp up and shortened the set time.
Blushing is no big deal if and when it happens, easy to clean and prep for the next step.

I also tried peel ply with good results. Being my first try at it, I had a slight learning curve but it does bring up air and excess resins with rolling the area. The excess resin is easily removed, Before it kicks without really disturbing the glass underneath. If your going to try peel ply, be sure to buy it with the pinstripes....it helps to find it after it's used...it tends to turn clear and disappear into the work and the pinstripes allow you to see where it is and where it aint...LOL.

It's easily pulled after set up/cure except in areas where there is a thicker layer of cured resin. It definitely does eliminate the blushing all together and leaves a perfectly textured surface for the next layer of glass....no clean up. Peel and lay the next layer.

It's not all that expensive to use.