Hi!

A friend of mine is working on a project of making underwater fishing spears from EC carbon tubes.

To avoid problems with the water pressure crushing or distorting the tubes, He is considering filling the tubes with a liquid ..

Radiator coolant antifreeze seems an obvious choice, since these mad underwater fishermen dive in from the ice in winter ..
 We all know that water expands radically when frozen, so that would certainly crack the tubes ..

How is the chemical tolerance of the different EC carbon tubes to Ethylen Glycol?

How do they stand up to temperatures down to -20 Celcius?   (They will not have to be anything but "stable" at these temps, once "in use" they will be above freezing..
(Can't dive in frozen water .. )

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Hi Dravis,

The temperature on its own would only increase the brittleness of the tubes, but if as you say they just need to be stable then there shouldn't be a problem in theory.

The Ethylene Glycol is going to be the problem as the chemical resistance of epoxy to it is only fair so over time you would expect degradation of the epoxy matrix.  Exactly how much of an effect, concentration etc and how quickly would only be determinable from testing.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant