Lew Hodgett wrote:

Bob wrote:


So my question is .................. given I can not use "the best"
tank material availible, I am looking seriously at plywood and epoxy
for a 25 gallon tank. What I have read from our experts is it will
either crack or start to smell becuase epoxy just does that.

Huh!

Done properly, epoxy/glass tank works just fine.

A 25 gallon tank is relatively small. I wouldn't waste time with a
plywood core.

I built a 65 gallon tank for my boat using 4 layers of 24 Oz double bias
glass and epoxy.

You could use 17 OZ double bias glass for your tank.

Build with a clean out port in top of tank (mine is about 12x16), held
in place with screws.

Line the interior of the tank with two (2) coats of "tank resin".

Build the tank with two (2) dip tubes for pump out. It simplifies the
plumbing.

Good luck.

Lew

I built a small foam cored tank for an airplane wing tank.
Urethane foam glassed inside and out.
about 3/8" thick foam - for the sides for the box and 1/8" thick foam
cored top and bottom.

The sides and the bottom skin were assembled with small amounts of
5 minute epoxy. Then glassed inside and out with 1/2 ounce fabric.
Inside got 3 layers, outside 2.

Then the top panel (already glassed and cured (and prepped) was taped on
with glass tapes.

We didn't use it because the dang thing weighed a ton (aeronautical ton,
folks).

But we all agreed it was for sure strong.

Vynalester resin is prefered for all fuel and water systems.
I use epoxy for laminating everything else.

Urethane foam was used here, but PVC would be better.

Urethane can not be hot-wired to shape, as it emits a cyanide gas
when burned (!).


Now, for a really low bucks approach, I've always wanted to use
corregated cardboard (prep with West Epoxy like plywood) and glass.

Kind of an industrial size version of Molt Taylor's TPG system?