> Could you explain exactly what type 1 exterior test is? My lumber supplier
> isn't sure what that refers to. (Where would it be purchased?)

Purchase in Canada or anywhere that has a similar spec.

The following specifications are for hardwood plywoods. 4. Types of bond 4.2 Type 1 (Exterior). The construction and adhesive bond of this type shall be so designed that the plywood will give satisfactory service when used under conditions of exterior or other severe conditions of exposure. Plywood of this type shall pass the cyclic soak and boil test specified in Clause 7.3. Paper tape may be used only when exposed on faces and backs. 7. Tests 7.3 Type 1 (Exterior) Test Test specimens shall be cut 6 x6 inches square. They shall be placed in water at a temperature of 70+/-5F and weighted so that all of each specimen is submerged for a period of 24 hours. The specimen shall then be removed from the water and dried at 145+/-5F for 24 hours. Each specimen shall be separated to allow a free circulation of air. The specimen shall then be placed in boiling water for four hours after whoch time they shall be removed and dried at 145+/-5F for 20 hours. This four hour boil, followed by drying at 145+/-5F for 20 hours, shall be repeated making two complete cycles. No specimen shallshow any delaminationat any time during or on completion of the test. Delamination which occurs at a defect permitted within the grade or in the wood adjacent to the glue line shall be disregarded when assessing the test results.

These specs apply to all marine ply fabricated in Canada, including okoume.

> As for MDO, I'm told it has a plasticised coating. Wouldn't that interfere
> with epoxy?

The last time I saw an MDO sample there was a paper coating on one side.

My perspective concerning marine ply is a little differnet as I am building a 45 foot catamaran.

Cheers Yan Stambouli