Kerdi membrane for plywood tanks
 

Anyone ever try to embed kerdi membrane into the epoxy of thier plywood builds?

I would still use chop mat and epoxy like usual... but on the last layer embed the kerdi..

I have no idea if it's compatible but I have to ask, why? Epoxy is more than sufficient for waterproofing, and if you're already putting glass in it, it'll be incredibly durable, too.

epoxy/ fiberglass resin is brittle at thickness without continuous layers of mat or cloth embedded in it...pretty sure if it cracks for any reason that water will quickly penetrate to the wood... kerdi would prevent it from ever touching the wood

Compared to what, glass? If the epoxy on an epoxy coated tank cracked, it would indicate movement and twist. That wouldn't happen with a properly built plywood tank and stand.

If you had that kind of movement, a glass tank would fail far sooner than a heavy duty plywood box coated with epoxy, IMO.

I agree. Brittleness of epoxy is relative. It's actually pretty soft, in terms of reefkeeping standards. Less brittle than glass. It holds up to impacts very well. When applied to wood, it tends to stay bonded, since wood is flexible, too. I made test panels when I did my big tank and hit them with a 20 ounce demolition hammer as hard as I could, and I couldn't chip, crack, or otherwise damage the epoxy. It's plenty tough.

And at the only interface with a significantly different material in terms of stiffness (the glass), you have a heavy flexible buffer (silicone).

Wood tanks are incredibly durable!