So I picked up some stuff from another builder in the area (very nice guy, thanks Mike!), and got a few bottles of old epoxy, and a LOT of it. And by the looks, its pretty old since the part A is very clear, but part B is almost brown. It is two different brands, both equally brown.

So I decided to test them.

I found out that one of the brands is SUPER thick, and cures very fast. It is also VERY hard. You can feel the heat during curing. I suspect it is no good anymore, at least for rod building. Doesnt say how fast it is supposed to cure, but its flex coat, so I assume slow. It cures slight yellow, and with an ever so slight haze.

The second batch (will update with brand later), it doesn't specify high or lite build, but its very thin, so I suspect it must be a lite build. It is very runny when mixed, and cures very slowly, maybe over 18 hours. It is fully cured now, and very flexible. It also cured with a slight yellow color, but very clear otherwise.

So, the batch that is good, is slightly yellow when cured. Other than discoloration, is there any reason I should not use the second, thinner epoxy?

Is there any practical application for the "fast" epoxy, where color is no consequence?

My plan is that I would just use the thin on dark threads where color is of no consequence or builds where perfection is no object, like practice, or my own beater rods. Just wanna make sure there are no other consequences I am not able to foresee.

Thanks guys!



Edited 1 time(s). Last edit at 07/24/2017 03:17PM by Earl Estrada.

Both will still work. The amber or yellow coloration is natural and won't be as noticeable in a thin application over thread unless you're working with a very light color - white, light blue, etc. Of course, given what epoxy costs (not much) you might be more comfortable with fresh stock in whatever epoxy product that you prefer.

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I'd wager the fast curing, heat throwing one is an adhesive epoxy and not thread finish.

It is Flex Coat, and appears to be for threads, at least the bottle says so. Makes me wonder, how old, and if some of the thinners are able to evaporate off over time.

There are no thinners nor solvents in these products. They are 100% solids epoxy.

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I am no expert, but I have been using epoxies for over 20 years, and I always thought the hardner was made with several solvents. In fact, after looking at 7 or so MSDS sheets just to check, and they all had at least one solvent, most of them having benzenemethanol, or benzyl alcohol. I am not sure how susceptible to evaporation those are, but I would assume there is also solvents in our hardeners, despite the fact that I couldn't find the MSDS for FlexCoat.

Earl,
The best and safest thing to do with all of the epoxy is to dump it and purchase new.

When you build a rod, you get a lot of money in materials and many hours of your time on some special builds.

Why take even a slight chance of using a product that may make your money and time spent to produce any thing less than a perfect product.

Be safe