I have access to fiberglass tanks used by local fish plants.  They are available in various sizes all with open tops.  They could be easily insulated for heat storage.  Can the fiberglass take the heat?  Does anyone have a fiberglass heat storage tank?

Don’t have one but did some research. Some can take the heat and some can’t, depends on how they are made. I think, but don’t rely too much on this, that FRP (fiberglass reinforced plastic) may be able to handle the heat, but I think even this is made in different grades. Essentially, it is a thermoset plastic which needs to be cured with heat before placed in final service. A used one in a heat application already should be cured.

I would be wary of a tank used for fish, and that is not a heat application. Check the manufacturer, get the specs, and be cautious.

I do have an FRP tank.  But, mine did contain hot oil in it’s previous life.  As jebatty said, it all depends.  If you can get a nameplate off the tank, you should be able to contact the mfg and get the specs on it.

tire man what part of novi? i have fisherman friends from wedgeport.

I live between Digby and Yarmouth. Approx. 40 miles from Wedgeport.

Probably depends on the type of resin used in the plastic… the three basic types are polyester, vinylester and polyepoxide (epoxy).

Epoxy is far and away the most stable, the strongest and the most expensive.  Polyester and vinylester are much cheaper, but in my experience, don’t cure as fast or as reliably, aren’t nearly as strong… but I don’t know how any of them would react to heat.  I’d guess epoxy would be the best for the application as it has far and away the most crosslinking and interchain bonds of the three.

That being said, I can almost guarantee the resin used in those fishtanks was not epoxy.  It’d be too expensive, I’d imagine.