Guy at the lumber yard was telling me that marine plywood is treated with copper and should not have screws of dis-similar metal ie:stainless or otherwise used with it. Anybody ever heard of this?
Marine plywood
- Thread starter cdwood
- Start date
uh, no. Marine grade plywood is rated as such for water proof glue for the plies, and no voids in the core plies. All knots are plugged on both sides.
Fir ply is the least expensive and fine if it's epoxied over, brunzeel or premium grades have nicer outer plies and generally more plies. There are a lot of grades of 'marine' plywood.
Use bronze if you can afford it, stainless if not.
BTW, bronze ring nails work great for plywood, as do clench nails and copper rivets.
What are you building? Old wooden boat builder here...
Fir ply is the least expensive and fine if it's epoxied over, brunzeel or premium grades have nicer outer plies and generally more plies. There are a lot of grades of 'marine' plywood.
Use bronze if you can afford it, stainless if not.
BTW, bronze ring nails work great for plywood, as do clench nails and copper rivets.
What are you building? Old wooden boat builder here...
Restoring my old 85 204c. Currently rebuilding the cross members on the gas tank that add support to the deck.
Ah yes. Stainless screws are fine. Drill pilot holes, use flush heads, and a counter sinker to set them flush. Fuller makes a nice assortment kit of one-step tapered pilot and counter bore bits, about $50. I just had to replace my No. 6 from using it with durock for marble and tile counter tops at the house.
Fir panel standard marine grade ply is fine for that. I really don't like to see screws into end-grain, so 3/4" oak or fir is recommended for framing where required.
I also suggest coating everything with epoxy so you never have to worry about them deteriorating. Get a quart of WestSystem and paint them once everything is built up. For hidden surfaces, pre-coat.
BTW, epoxy is the only thing that will stick to cured fiberglass. A lot of buys make the mistake of trying to recoat with polyester resin, but it will peel off readily. Ply to 'glass joints can be done with glass mat and epoxy.
Seems to me Grady uses some kind of 'green' treated marine ply, but then they don't encapsulate everything under-deck. We all now realize it doesn't last forever. A proper repair will.
Fir panel standard marine grade ply is fine for that. I really don't like to see screws into end-grain, so 3/4" oak or fir is recommended for framing where required.
I also suggest coating everything with epoxy so you never have to worry about them deteriorating. Get a quart of WestSystem and paint them once everything is built up. For hidden surfaces, pre-coat.
BTW, epoxy is the only thing that will stick to cured fiberglass. A lot of buys make the mistake of trying to recoat with polyester resin, but it will peel off readily. Ply to 'glass joints can be done with glass mat and epoxy.
Seems to me Grady uses some kind of 'green' treated marine ply, but then they don't encapsulate everything under-deck. We all now realize it doesn't last forever. A proper repair will.
Been using the stainless all along, just thought I'd put this out there. Also I am a strong believer in epoxy coating everything. No piece of wood has gone back into this boat without at least 2 good coats, usually they get 3. Am just about to finish my 3rd gallon of West since I started this project.