Tricoya vs marine plywood

[2copplane]

im fitting my 9’x3’ cockpit sole with 35mmx5mm iroko slats. I’m using iroko as teak is way too expensive. £65.00 vs ££££. I‘m not sure how the iroko will last so my plan is to make it removable by epoxying to 9mm marine ply. However I’ve come across a product call Tricoya which is an MDF that is guaranteed for 50years and seems pretty much impervious and rot proof. It isn’t cheap but then nor is the 25year guarantee marine plywood.

The board will be fully supported by the grp cockpit sole, and as an experiment I was going to bed on some butyl tape and a few screws to prevent and movement.

any other suggestions for the backing board gratefully received.

 

[IanCC]

Tricoya is good stuff for sure.

 

[Tamar]

Plywood seems to be hit and miss these days. I just cut a sheet of 18mm"marine"plywood and there were a few voids in the cut edges. I took the offcut back and it was the most difficult job to get a refund.
On the other hand I was given another sheet of exterior plywood for a repair of my wheelhouse and it was perfect.
Tricoya sounds interesting

 

[Rappey]

I‘m not sure how the iroko will last

At 39 years old my cockpit teak slats have lost around 3-4mm in thickness but the Iroko slats on the cockpit sole still look as good as the day they were fitted.

 

[Hacker]

I think that Tricoya is similar to Accoya (MDF v softwood but both undergoing accetylation). If so, Accoya doesn’t look like it is warrantied for salt water. It has 25 yr for freshwater. Accoya is also extremely wearing on tools; planes and chisels need very regular sharpening.

 

[DownWest]

Iroko would be my choice. Lots of it on pontoon decking, seems to last. And, used it in the main structure of my faering. Good stuff, if hard on cutting edges.

 

[WLane]

Iroko is good stuff and will last if looked after, the others are right. Tricoya is fantastic stuff and is derived from accoya. Accoya is not guaranteed for salt water as I'm sure I read a while ago that is can be subject to bug attack (can't remember the exact one) but pretty sure it's when fully submerged. It's rarely used as a substrate board though, as it's so expensive. Mainly used for finishing.

Things like rendaboard, calcium silicate or one of the other aquapanel exterior grade boards would be the way I'd go. They're relatively heavy (but not ridiculously) but dead easy to cut with a tungsten cutting knife by scoring. They'll outlive fibreglass tbh.

 

[Rappey]

Iroko would be my choice. Lots of it on pontoon decking,

Are you sure ? Pontoons in the uk are usually decked with balau.
I don't think marine ply can compare to tricoya when tricoya is guaranteed for 50 years above ground and 25 when under.
Tricoya is nearly 3x more expensive than marine ply.
I've used 18mm phenolic ply that nearly looks like smooth formica on one side and textured diamond anti slip on the other. It's birch ply bonded with phenolic resin.
After laying outside for 6 years it's still not showing any signs of deterioration and I didn't seal any cuts.

 

[2copplane]

The Tricoya MDF has arrived and boy is it heavy stuff, and for 9mm extremely rigid.
I’ve decided to assemble and caulk the iroko and then I will epoxy it to the mdf. My approach has been to staple it face down onto a plywood covered with waxed polythene sheet and then filled the 5mm gaps with caulk. After a couple of days I peel it off and it looks pretty good, though I want perfect so may scrap this batch and try again. I think this method will minimise sanding.

The issue is I started with a 8”x2” rough sawn slab which I ripped into 5mm slats. Once cut the slats take on a life of their own though using staples I can pull them straight. The big mistake is is I then take each (bent) slat and trim it down to 35mm, and due to the bends isn’t consistent. What I will do next time is get a planed and thicknessed plank 8”x 35mm. The iroko was only £65 so not a great loss- imagine if it was teak?

 

[Bodach na mara]

Plywood seems to be hit and miss these days. I just cut a sheet of 18mm"marine"plywood and there were a few voids in the cut edges. I took the offcut back and it was the most difficult job to get a refund.
On the other hand I was given another sheet of exterior plywood for a repair of my wheelhouse and it was perfect.
Tricoya sounds interesting

Not just "these days." I was putting a cabin roof on a 1912 6-metre in 1968 and had purchased what was described as BS 1088 Marine Plywood, one sheet each of 1/2 inch and 3/8 inch. Each sheet had a core void of at least 1/8 inch. I took it back and it was grudgingly replaced but not before several people in the company had told me that I was making a fuss about nothing and that they sold hundreds of these sheets to boat builders who never had any complaints.