Marine Plywood

gfilipi

Member I
Hi All,

I'm in the process of replacing the head cabinet and the sink top due to rotting wood. It currently has 1/2 plywood with a white laminant on the top side.

My question is. Can I use any 1/2 plywood (such as Home Depot plywood) and then laminate a new white formica top and paint the bottom side or do I have to use marine plywood. If I can use any plywood, what wood type do I use.

Marine plywood isn't easy to find. Ideally I would like to buy plywood that already has the laminant attached to it. Does anyone in the SF Bay area know where to get marine plywood?

Last question. In what situations do I want to use marine plywood in the boat.

Gene
Finesse
1986 E32-3
 

jmcpeak

Junior Viking
...In what situations do I want to use marine plywood in the boat?

Personally, I don't know of any. Just apply 3-4 good coats of a good marine varnish (Varethane, MinWax Helmsman Spar Urethane, etc) to keep the wood from drawing water.

Just my 2 cents on how to help keep costs down.

Jason
 

gareth harris

Sustaining Member
There is a difference to the bonding procedure, and marine plywood will last longer, but Gene is right in that it is much more expensive.

I am using marine plywood in my rebuild (most of the boat), I figure the amount of work involved justifies the extra money. I had to go over two hundred miles each way for it from where my boat is, but in SF it should be more readily available from specialist wood sellers.

Gareth
Freyja E35 #241 1972
 

Emerald

Moderator
Not only should it have better glue, but marine plywood should be better quality, e.g. fewer and smaller voids or "voidless". Think you'll also find it's a better grade of wood. That said, put on 2 coats of epoxy on either exterior grade plywood or MDO (medium density overlay), and you should be OK for what you are doing, and keep cost down some. Just another set of options to ponder.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
glues and leaks and plys, oh my

Back in the 60's, "marine" plywood designated a product without voids, and of course it used waterproof glue.
By sometime in the 80's (?) all the plywood makers had switched to waterproof glue for all grades. The difference in the inner plys not having voids was then the determining factor for the high-end product, i.e. marine.
If you are backing up an non-load panel inside your boat, and the surface is overlayed with plastic laminate, any modern plywood should do the job.

The unmentioned "elephant in the room" in this whole thread is what happened to allow the original panel(s) to rot. I hope that the leak was permanently fixed that allowed water inside in the first place.

Best,
Loren
 

gfilipi

Member I
Handloggers

Hi All,

Thanks for the suggestions. Hand Loggers is a few blocks away from me. I drive by it everyday and have never noticed it before.

As for the leaks, I believe the initial damage came from a lacky 1st owner with a combination of a leaky Dorad and water coming in from the bow pulpit from the bow light wire. Both were fixed. Researching this site; quite a few have had the same problem in/around the same vintage of 80's Ericsons. I believe the direct water damage to the wood in the head came from a leaky portlight over time. I've replaced all the opening portlights and hatches and everything has been very dry during the heavy rains the last few week in SF Bay. I'm going to replace the 4L/4R on both sides as well.

I've made the hard decision to pull down the headliner and rebed all of the deck hardware and replace/upgrade where needed. If I do it right the first time, I'll have less head ache's from leaks in the future. I'm going to start in the front of boat and work my way back to the stern.

What's a few more/many dollars in the restoration project? It's already way over budget. The boat dollars all blend in after awhile anyway. My wife will have to wait on the new cushions and dodger.

Gene
 

NateHanson

Sustaining Member
Most areas have "Plywood dealers/distributors" that deal primarily in sheetgoods. Around the North East it's Atlantic Plywood. You can get just about any wood sheet product from places like that.

(And I'll add for any New England folks that Boulter Plywood, Somerville, MA is an indispensible local shop for boat-building woods, veneers, and sheet goods.)
 
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