Plywood/Lumber recommendations in Seattle

[Hunter36Naiad]

Say everybody. I'm planning for some refit projects on my Hunter. I'm in Seattle and I'm looking for local advice on specific plywood products form specific vendors. I can get the standard doug fir AB marine stuff from a number of places for around $100 for a 1/2in sheet. I can go up to Fiberglass Supply in Burlington and get 1/2 pvc foam (Divinycell) for about $150. I even have some AB marine lying around and I might use PVC for some projects.

What I want to know is among a endless plywood options available outside of these marine products, including those widely discussed online as boat building alternatives, what is actually available in this area that is good and under a $100 a sheet (1/2in). Think mainly for bulkheads and as misc coring material, not the hull.

Any other AB stock out there not labeled for marine use? Any ACX stuff that is actually voidless in practice and of a suitable species? Obviously I've perused the catalogues but I would love to hear specifics from experienced locals.

Bonus would be thoughts on good dimensional lumber options for misc supports and such that is up to the task and of a good value.

Thanks

[coopec43]

In Australia I'd be looking for exterior ply or structural ply. (both mean they have waterproof glue).

Once you pick out ply that looks OK I'd be checking that it complied with the appropriate Canadian Standards.

https://cwc.ca/how-to-build-with-woo...ducts/plywood/

I don't see Divinycell as being an alternative to plyboard but more complementary. (I used Divinycell on my deck)

[mlydon]

M’y advice is, don’t skimp here. A sheet of regular ´good’ birch ply is going to cost you $50. It’s not as if you’re sheeting a house. If you go through 10 sheets it would be a lot, and do you really want to use something questionable to save a few hundred dollars on materials, when spending many THOUSANDS on your labor?

Buying the right materials only hurts once.....

Matt

[Hunter36Naiad]

Any locals out there with specific thoughts? Marine ply at $100 a sheet is not a bad deal, but I still want to know what other options are out there.

And what about lumber? Doug fir is readily and cheaply available here but I've heard that while it's very hard and great as plywood, it can warp over time making it less that suitable for supports you are going to glass over for example.

Tell me different.

[coopec43]

You could use marine ply if you don't care about the cost. (While you are at it you could replace all your engine bolts with 316 SS bolts as well!!!)

[Hunter36Naiad]

Originally Posted by coopec43

You could use marine ply if you don't care about the cost. (While you are at it you could replace all your engine bolts with 316 SS bolts as well!!!)

What's marine ply?

[ewsponberg]

Originally Posted by Hunter36Naiad

What's marine ply?

Certified marine ply comes with 3 guarantees: 1) there are no voids in any of the layers, 2) the glue holding it all together is waterproof, and 3) all of the layers are the same thickness, and there are generally more layers than in non-marine ply. So the easiest way to tell a marine ply, other than looking at a label, is to inspect the layers of wood at the edge--they should all be the same thickness. Some marine plywoods have hardwood facings like teak, birch, ash, or maple. These are better for interior clear finishes (varnish) where the wood grain shows. Other marine plywoods have softwood facings such as Douglas Fir or Spruce. These are generally better where the surfaces are covered with paint, cloth, Formica, etc.

Eric

[delmarrey]

Another thing for quality is the amount of layers in the ply. 5 layers is usually the cheap stuff and can delaminate easy if it gets wet. 7 layers is fairly common. More then that starts to get expensive.

[Matt Johnson]

I'm not saying this is a best practice, but if painting the interior, one option is to use MDO plywood (typically $75 sheet). It's used raw (no additional coatings) for large billboards/outdoor signs, so it's has to be smooth, low rot, and stable in all weather conditions. MDO is the waterproof layer applied to each face of the plywood, but the base ply has all the characteristics of a good marine plywood to keep that surface stable- typically at least 7 layers; waterproof phenolic resin glue; no voids; and even ply layers.

The negative with MDO is the weight... it's not light.

Matt

[coopec43]

Originally Posted by delmarrey

Another thing for quality is the amount of layers in the ply. 5 layers is usually the cheap stuff and can delaminate easy if it gets wet. 7 layers is fairly common. More then that starts to get expensive.

It won't de-laminate if it has waterproof glue. In Australia we have Exerior Ply and Structural ply - both have waterproof glue. (I am using Structural ply for the base of my double berth. It is not pretty as it has knot holes)

Here are some more standards but you'd probably find them uniform in many countries.
https://www.internationaltimber.com/...l-definitions/

There's a stack of suppliers in Seattle.
https://www.google.com/search?q=plyb...0049287108;mv:[[47.8866775945083,-121.68582103730468],[47.36745894963328,-122.67871044160155],null,[47.62771299918158,-122.18226573945311],10]

[delmarrey]

Originally Posted by coopec43

It won't de-laminate if it has waterproof glue. In Australia we have Exerior Ply and Structural ply - both have waterproof glue. (I am using Structural ply for the base of my double berth. It is not pretty as it has knot holes)

Here are some more standards but you'd probably find them uniform in many countries.
https://www.internationaltimber.com/...l-definitions/

There's a stack of suppliers in Seattle.
https://www.google.com/search?q=plyb...0049287108;mv:[[47.8866775945083,-121.68582103730468],[47.36745894963328,-122.67871044160155],null,[47.62771299918158,-122.18226573945311],10]

If the ply is submerged long enough the wood starts to soak up the water. Especially, rain water. Don’t ask how I know!
E.g. a main bulkhead next to a keel stepped mast.

[Shrew]

I don't think you need "Local' knowledge. Plywood concepts are universal. Your best bet is Marine Plywood, for the reasons described in Post #7.

Structural plywood can come in A and B bond type. You really want A-bond type.

Type A bond uses a phenol-formaldehyde resin which is specified for marine and exterior plywood and will not weaken under wet conditions, heat, or cold.

Type B bond uses a melamine fortified urea formaldehyde resin and is suitable for exterior applications including concrete formwork.

Type C and D bonds use urea-formaldehyde resin and are both interior bonds and are not recommended for structural applications.

Exterior Plywood does include waterproof glues, however it is NON-Structural.

Marine Plywood is essentially Type A Bond, Structural plywood with no vacuoles. That is what you want to use.

Nobody cares that they save $100 on a project, when they're tearing it apart. To do it right, is to do it once.

[coopec43]

This site might provide further information


https://www.internationaltimber.com/...dwood-plywood/


Marine grade Hardwood Plywood

• General moisture resistant applications: Bathrooms, kitchens and external applications but not intended for boat-building

Now I'm confused!!

[s/v Jedi]

Most marine plywood is fake. They sell it at the Lowe’s here and I wouldn’t even want it under my roof shingles.

Real marine plywood is built from hardwood veneers like meranti only and all layers are the same. Bruynzeel is the real deal.

I can get real marine plywood here in Florida but it’s hours driving. For interior projects I am using cabinet quality birch plywood (nothing like real Baltic birch plywood) from places like Home Depot and Lowe’s. After cutting and fitting a panel, I coat it with penetrating epoxy thinned 40% with denatured alcohol, then sand it flat and smooth. You basically end up with a plywood core that has a fiber reinforced plastic skin. For finishing you can paint or varnish. I also tried staining before epoxy and while that works, you get much less epoxy in the wood so that is not recommended.
The picture is a panel after epoxy and sanding, ready for laminating.

[fourlyons]

To answer the OPs question about getting marine grade ply in Seattle, I have used Crosscut Lumber and Comptons for years, both in Sodo. They both also have an excellent selection of foreign and domestic lumber; Sapele is comparable in price to quality Doug fir, but superior.

Also the suggestion to use the sign board, known as MDO 2 sides, is an excellent one, I've also successfully used it for years.

All ply of any type must have the edges well sealed.