Another I screwed up....advice?

Now that I'm getting into bigger fiberglass kits I figured it was time for a better epoxy other than the 5,30,60 min 50/50 stuff I've been using on other tube types.I ordered some West epoxy from Tim and after priming the pumps into to 2 different cups I figured why waste it and do some external fillets.So I poured the hardener into the resin,mixed well, then added some silica to desired peanut butter consistency,meanwhile in another cup made a batch with carbon fiber for internal fillets(one pump of each in single cup).You know 2 birds one stone thing and noticed a weird smell while dumping the fiber mix in.When I turned back to other table the silica mix was smoking,boiling and starting to expand rapidly so I picked it up by the mixing stick and tossed outside.After it cooled I took the pic below.As seen in pic the fiber mix was fine but silica mix was less than desirable.

So my noob questions are....
Is this a result of to much hardener from the priming pumps process?(what I expect happened)
Is it possible to add to much cilca and cause this to happen?(I don't see that it could but I am a noob to this type of epoxy)
Are these type of disposable cups a bad idea?

So, this was West 105 and 205 right?

Oops my mistake it wasn't West.Just looked at my receipt its Proline 4100.

Sounds like too much hardener. Check your mixing ratio's.

I'd say it sounds like thermal runaway on the epoxy (although I would think the Proline stuff would be very slow cure). To keep from having this effect, you need to mix the epoxy in a more shallow container (I often use Chinet plates that have the nice lip on them) and let it stay spread out while you mix in additives and subsequently apply it.

dixontj93060 said:

I'd say it sounds like thermal runaway on the epoxy (although I would think the Proline stuff would be very slow cure). To keep from having this effect, you need to mix the epoxy in a more shallow container (I often use Chinet plates that have the nice lip on them) and let it stay spread out while you mix in additives and subsequently apply it.

Click to expand...

Yep.

Epoxy is exothermic (generates heat as it reacts), and it's also accelerated by heat.

What happened is your epoxy cooked itself. The silica likely exacerbates it, which is why it kicked off and the other didn't.

Yogurt containers, pudding containers, sour cream containers.....you get the idea -- they all get saved around here, and used for mixing epoxy. I've used ice cream buckets for relatively small batches (relative to bucket size) when mixing largish batches outside on a warm summer day, so that it doesn't kick off like that.

-Kevin

dixontj93060 said:

I'd say it sounds like thermal runaway on the epoxy (although I would think the Proline stuff would be very slow cure). To keep from having this effect, you need to mix the epoxy in a more shallow container (I often use Chinet plates that have the nice lip on them) and let it stay spread out while you mix in additives and subsequently apply it.

Click to expand...

tim is 100% correct. dont mix in a cup or a bowl you need to spead it out. I usually use paper plates.

good luck!!

stickershock23 said:

tim is 100% correct. dont mix in a cup or a bowl you need to spead it out. I usually use paper plates.

good luck!!

Click to expand...

How about the plastic lids that come on large coffee cans? Then when you are done you can lift the harden mixture off?

RocketManDan said:

How about the plastic lids that come on large coffee cans? Then when you are done you can lift the harden mixture off?

Click to expand...

Usually not enough of a lip for these types of epoxies -- the viscosity is too low, and they'll run all over.

I can usually get several uses out of things like yogurt containers, by doing exactly what you say -- pop out the old, and use it again!

-Kevin

THX for the pointers fellas.I did a couple more batches before checking back here in same type cups and was much less eventful.So it seems when I mixed the two from when I primed my pumps I had to much hardener in that first batch.

On a side note I'll take the advice of mixing in something else like the Philly cream cheese containers on hand....