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 .. )

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

Update!

We solved this problem in another way ... The tubes will be filled with epoxy resin with added low density filler ..  I found a way of reducing the density  to slightly below that of water.
(it involves nothing more sophisticated than a bucket of tapwater in which I suspend the mixing cup of resin and stir in filler until the cup floats with the level of resin equal to the level of water .. )

This also greatly enhances the strength of the "spears" and protects against crushing them..

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)