Waterproofing plywood?

[supermanlives]

fibre glass

 

[trichrider]

GACO SHIELD

 

[ChrisGGG]

I think they sell some fiber glass mat and resin at most Ace hardwares. The is also a Killz spray sealant they sell in the garden areas of Lowes/Home Depot for ~$10.

 

[Scottish Research]

MACROPOXY® 646 PW Potable Water Epoxy (Part A), Mill White

The paint should be water potable.

Trying to get a quote per gallon.

Pond Armor is another option.

R.Fortune

 

[TLoft13]

.Waterproofing plywood....

You can always fiberglass your plywood box/tank, a bit expensive but it holds forever.