Product to seal external ply?

I want to use WBP (Water and Boil Proof) ply externally to the edge of some outdoor furniture - tables, planters, benches. As a design detail the edges will be exposed to the elements. Obviously I am concerned about water getting in.

Can anybody recommend a product that can be applied to the edges to ****** water movement into the ply?

Hardwood lippings glued secured with a loose tongue. Not a commercial product, but a professional joinery solution. To be honest, though, WBP ply is not really meant to withstand extremes - for that you need to specify the much more expensive marine plywood, or go to an all hardwood construction using a suitably durable species (e.g. iroko, teak, oak, etc)

Scrit