FT: Frame (Twin) Seat-base wood thickness

[Flyinglow]

I made my new seat base from 7/16 marine ply after I found my 1949 seat base had delaminated!! I cut the new base very carefully and rounded all edges.I then liberally coated it with Penetrol wet on wet coats after I drilled the holes. I re-used my original Dunlopillo foam which overhangs the base by about 1/8". All metal parts were soda blasted and epoxy coated.

Albervin, thank you.
Think I'll go the same way but with 1/2" board.

 

[timetraveller]

Just to make it clear about quality of marine plywood. A proper marine plywood will have both waterproof glue and hardwood veneers. Cheaper ones will only have the waterproof glue. The real thing is expensive so the best way is to find a local boat builders who will sell you an offcut. Regarding epoxy, there are special thin epoxies intended for wetting out timber in order to make fully timbered boats, i.e. no metal fixings. The WEST epoxy system comes to mind but you might have to pay over the odds for small quantities by buying online. I have no connection with that company but I know people who have built boats with it. Other companies produce a similar product but make sure you get the thin liquid. Do not make it thin by using a solvent. That produces bubbles which will mean that the end product will be non waterproof in the long term.

 

[Cyborg]

I’ve used gallons of West System Epoxy, but have never tried thinning it and I don’t think they carry a saturating epoxy.
This stuff is made locally and is made specifically for sealing things. 50/50 solvent mix. There are other versions out there, but it’s not cheap so not really worth considering unless you have other uses for it. They refer to it as a primer which suggests it needs a top coat, but I’m guessing that’s because it has zero UV resistance. I used this and then top coated it with Marine Varnish… not that the seat base will see any sun.
Bazlerker… if you ever need any, I think Cargo East sells it. Assuming they are still in business. At the end of the day, a good paint will do.

 

[Cyborg]

I made my new seat base from 7/16 marine ply after I found my 1949 seat base had delaminated!! I cut the new base very carefully and rounded all edges.I then liberally coated it with Penetrol wet on wet coats after I drilled the holes. I re-used my original Dunlopillo foam which overhangs the base by about 1/8". All metal parts were soda blasted and epoxy coated.

I have a 1947 Chris Craft U22 and the marine plywood delaminated. Fortunately they only used it for the floorboards under the battleship linoleum and the dog house (engine cover) so the rest of the boat isn’t likely to unfold.

 

[Bazlerker]

Bazlerker… if you ever need any, I think Cargo East sells it. Assuming they are still in business. At the end of the day, a good paint will do.
Thanks…the seat base that I made in the mid-eighties from 1/2” marine grade plywood and sealed both sides was in remarkably good condition so I reused it..

 

[timetraveller]

WEST stands for wet epoxy saturation technique and was developed specifically for structural strength in both ice and water sail yachts. It is thin so that it can penetrate into the structure of the wood and, like all the other epoxies I know of, is not UV stable. I have used varnish over the top of it and suggest that a paint would be better protection.