Need more work time with QCM resin

BLOODTYPEZX10R · Post by **BLOODTYPEZX10R** » Sat Feb 04, 2012 5:17 pm

I work with QCM-now Forest paints resin system. Resin EMV 043 and hardender ECA 324. The resin system is mixed 5:1. Has anyone tried to mix it 6:1 or somewhere in between to gain a few extra min.? This is the resin system that requires 150*-180* to cure correctly and if I go up to the longer work time resin hardener the heat goes up to 190*-210*.

My last set-up was ruined as the resin "froze" on me before I even got it in the press-I needed at leat another 15min. I hate it when this happened it has ruined a hundred dollars of materials.

vinman · Post by **vinman** » Sat Feb 04, 2012 6:01 pm

You can try a few things but I would not mess with the resin to hardener ratios, this will only screw up your epoxy and it won't cure correctly.

1: mix smaller batches. I weigh out 5 separate containers of resin and 5 of hardener. Each batch equalling ~200 grams of mixed epoxy. I mix them as I need them. When I tried mixing larger batches, say 500g, I found the epoxy would kick before I could use it all. Using smaller batches mixed as I go fixed this for me. I typically only use 4 batches or ~ 800 g of mixed epoxy, the last is kept in reserve, unmixed just in case I need it. But usually it goes back in the can.

This will give you plenty of time to wet out your layers and not have your epoxy kick too fast.

2. Mix in a larger container, keeping the epoxy mixed in a smaller container seems to make it kick faster.

BLOODTYPEZX10R · Post by **BLOODTYPEZX10R** » Sat Feb 04, 2012 7:14 pm

Thanks Vinman, yes I had read this I believe from you in the past. How much work time do you need for a lay-up. I have so many components to assemble and have thought and tried to use multiple trips to the press but no matter what I do I still need to lay-up all at once.
I will give your suggestion a go-I swear this last time I was going to do that but excitement turned to a frozen mess. I'm telling you it went so fast I was shocked-10 seconds, as I dumped out some it froze over 1/2" thick.

sammer · Post by **sammer** » Sat Feb 04, 2012 9:51 pm

Working in a cooler shop really helps.
The one time I heated the dungeon was close to disaster with epoxy kicking as I worked.
As Vinman said mix smaller batches, get it spread out then mix the next.
Like Vinman I'll weigh out 5 or 6 200g cups of resin then as I go I'll put them on the scale and add the hardener.
Once it's spread out you'll find you have a lot more time as it can't build heat.
Your epoxy mix needs to have 150f to cure so it must have been pretty close to that when you poured it out of the cup.
Don't mess with your ratios, you'll have nothing but problems and waste a lot of time and materials.

Good luck next time

sam

skidesmond · Post by **skidesmond** » Sun Feb 05, 2012 7:48 am

What they said, smaller batches in a larger container. I had batches I mixed in the red beer cups kick in and melt the cup and it gets very hot.

SHIF · Post by **SHIF** » Mon Feb 06, 2012 5:39 pm

I used QCM 0043 resin with 408 curing agent which has a 45 minute pot life according to the old literature. And like everyone says, multiple mini-batches is the trick. The curing agent is water-thin, I transfer it into an empty tin container so I can attach a cheap plastic hand pump. These always dispense 26 grams of curing agent per shot so I weigh out six paper cups with 104 grams of resin each prior to a build session. Then I simply pump and go, an epoxy mini batch on demand.

I now use Resin Research epoxy because it is totally colorless and also easier to acquire. It has a 50 minute pot life. Both components are pumpable but I still weigh out the resin and pump the hardener.

-S

SkiTheNortheast · Post by **SkiTheNortheast** » Mon Feb 06, 2012 6:00 pm

how is the viscosity on the Research Resin?

And when was the last time you ordered QCM? Because I'm not sure if forrest paints continues it anymore.

SHIF · Post by **SHIF** » Mon Feb 06, 2012 6:18 pm

RR Composite Pro system epoxy is lower viscosity than QCM and it truly wets-out the fabric quicker. Not twice as fast, but noticably faster.
The resin and hardener are both watery enough to use a hand pump if you want to.

Here is a quick review i posted on another thread:
http://www.skibuilders.com/phpBB2/viewt ... 7&start=35

Unfortunately the big storms have not happened for us yet this season so I have not tested the RR skis yet. But heavy flexing by hand and they seem exactly as solid as any skis I've made using QCM.

And the last time I bought QCM was when they still made it and Forrest was not in the picture.

-S

BLOODTYPEZX10R · Post by **BLOODTYPEZX10R** » Wed Feb 15, 2012 8:53 pm

Yes epoxy that was once made by QCM is offered through Forest paints. I spoke with brenda just a week ago. They are working on getting info up on thier website.

I got through the work time issue on my last board.....but I have a new issue. I really don't want to go to a longer work time epoxy because of the elevated cure temps.

SHIF · Post by **SHIF** » Wed Feb 15, 2012 9:17 pm

BLOODTYPEZX10R wrote:...I really don't want to go to a longer work time epoxy because of the elevated cure temps.

Epoxy pot life is not proprotional to cure temperature but rather determined by the particular chemistry.

You should use a heated press to achieve maximum strength from any epoxy system. Post-cure cooking is where the magic happens. Read the article, paragraph 1:
http://www.skibuilders.com/articles/epoxy.shtml

-S

BLOODTYPEZX10R · Post by **BLOODTYPEZX10R** » Wed Feb 15, 2012 9:41 pm

Uh, yes of course I use a heated press. The resin system is designed specifically with heat cure. I just don't want to have to heat to higher temps to get longer work times.
Thanks read that article some time ago-I would like to know what happened to Greg. I had spoken to him on some occasions.

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Need more work time with QCM resin

Need more work time with QCM resin