FX-1 US composites 3:1 resin dry time?

[swapmeet]

Sorry for the random thread, but i'm a little concerned.

So I mixed my 3:1 resin tonight, added Cabosil like Tom21 suggested to stick on my sponsons.

Maybe its just me but this stuff takes forever to harden up. Its cold here, but i have a propane heater in my shop. Its probably 65-70 deg in there.

After about 2 hours its starting to frim up a little. I assumed the 20-25min pot life meant that it started getting firm after that. Is it just too cold in my shop or am I expecting to much. (or both?)

 

[bobob729]

give it some time..

 

[2010brandingo]

probably too cold.

 

[BBYamaha]

I mixed up some tonight as well with micro beads and after 2 hours it was still a little soft. I just left it to set over night..

 

[XJCrawler]

I found when ever I mix it with Cabosil, it takes longer to harden

 

[davidy]

It takes a bit probably won't be real hard until next day and the thinner you spread it the longer it takes to cure

 

[Aircraftsalz]

It takes 4-6 hrs in my shop at 70-80 deg, not fully cured hard until 24 hrs.

Used a lot of that 3:1 with my builds

 

[swapmeet]

Ok thanks ya'll.

I guess I get so impatient that when I 'freehand' or without really measuring I always mixed it a little hotter, had it fully harden in a hour LOL.
Its like 20* here, and I turned the heater off when I was done working. (Propane isn't cheap!)

This weekend should be in the high 60's so hopefully i'll be able to make a little more progress. Any harm in putting a little extra hardener in the mix? Make it 3:1.5 or something?

 

[Mark44]

Mix as recommended, for small amounts I use a cheap plastic postage scale and measure weight 3:1. For large amounts purchase the hand pumps they make it simple.

 

[Matt_E]

Put a heat light on it.

And metered pumps are damn near mandatory.

 

[IS0LD0UT]

When I did my footholds. In 60 degrees it took a few days to full cure.

 

[gc4]

I'd give it a solid 12h at least before I'd start getting worried

 

[swapmeet]

Mix as recommended, for small amounts I use a cheap plastic postage scale and measure weight 3:1. For large amounts purchase the hand pumps they make it simple.

I was making the buttery goodness to glue on a entire sponson... so the pumps were handy.

 

[WaveDemon]

you can mix poliester resin at a higher rate to get it to harden sooner, not epoxy.

Matt is right, put a work light on it to get it to harden.

 

[Waternut]

Most resins and glues are tested at around 75°F and a specific humidity. If you go down to 65, it'll take considerably longer. A couple years ago, I mixed 4:1 properly and after 2 days of sitting in my garage where it only got up to 60°, it was still tacky. I went out and bought a small space heater and cooked it for 45 minutes and it was rock hard. Epoxy based products love heat. If you can get it to around 100-125° on the surface, it'll cure in no time.

Technically though, even in the right conditions, 3:1 shouldn't be hard enough to sand until 7-8 hours. I've sanded in 4 hours before with the help of the space heater but you need to monitor it.

 

[smoofers]

Also, remember to thoroughly mix your resin and hardener BEFORE you add the thickening agent....

 

[Flash-FX]

The instructions say for the medium hardener...

* Mixing Ratio by Volume: 3:1
* Pot Life: 20-25 Min @ 80F
* Set Time: 3-4 Hours
* Drying Time: 8-10 Hours

Pot life is usually a cup (100 gram mass). As the mass will cure faster than a thin film. In this case it's all rated @ 80 degrees.

Sounds like you need to add some heat, let cure, then sand in a day or two. Next time order the "fast" epoxy/hardener system when working in the colder shop.

BTW, you CAN NOT guess with mixing ratio's of epoxy. You MUST use a scale and measure by weight, or at least the volume method! The US composites epoxy is good stuff if mixed correctly.

Good luck, Where's more pix?

 

[Mark44]

Also stir the resin with a round dowel and not a flat stick. It will help keeping the aeration out of the mix.

Mark44