What wood to use

dlochner · Jun 17, 2020

The cost of marine plywood is due to the veneer, some exotic tropical wood, the number of plies in the wood, and the absence of voids in the plies. The number of plies and the lack of voids makes the plywood stable and less prone to warping.

For your purposes, a decent quality cabinet grade plywood would work well. Cabinet plywood has more plies than standard sheathing plywood and has no voids or only very small ones. Both sides are smooth and ready for a finish. The cost will be less than marine, it will be just as stable and with staining or painting it will look fine. Cost per sheet will vary based on the outer veneers. Oak and Birch are common and probably less expensive than Cherry.

dLj · Jun 17, 2020

Lots of options. How good of a wood worker are you?

Some pretty simple solutions are using standard grade plywood finish of your choice and applying epoxy finishes on all surfaces. For interior work that really works just fine. In my opinion anyway...

You can use inexpensive plywood and stain it to what you want for finish color. Then use epoxy top coats to seal. You should get all cut surfaces coated with the epoxy. Essentially, each piece becomes encapsulated in epoxy. Just check that the stains you use are compatible with the epoxy. West System has a list you can check out if you want to go that route.

dj

TomY · Jun 17, 2020

fred1diver said:
Hey everyone, I need to redo some cabinets inside my Grampian 26 as there is too much water damage on the cabinets, not worth trying to revive them, I ‘m looking at marine mahogany but wow is it ever expensive, it would cost me more in wood than what I paid for the whole boat lol so what other marine wood would you recommend?

You ask for wood so I'm assuming you're making some cabinets out of lumber. I like Sipo because I can get it a mile down the road at my local lumber supply, and the price is pretty good. About 8-9 per board foot.

Sipo is a tropical hardwood that resembles mahogany. I use it on my boat in place of real mahogany as after I varnish it, it looks just like the 60 year old African mahogany much of my boat was built of.

Here's a comparison of Sipo against a piece of that 60 year old mahogany and a piece of cheap Luan plywood (I used filler stain on that to match the hardwoods).

Here's the finish cabinet I used the above pieces for.

Sipo, luan, mahogany CCRed stain in place.jpg

dLj · Jun 17, 2020

fred1diver said:
At the moment I’m looking for plywood

Are you going to try to match existing pieces that are not getting replaced or are you thinking to rip out everything and rebuild? Matching can be a pain. Ripping everything out is lots of work. Ya can't win... LOL....

Birch plywood is pretty low cost, takes stains pretty well and sealed up with epoxy will last many years...

dj

rgranger · Jun 17, 2020

If you go with a plywood option, be sure the plywood was constructed with waterproof glue. The cheap stuff at Lowes and Home Depot have colored stripes on the sides of the stacks (not recommended but) The water proof versions have green stripes on the side of the stack. If they have black stripes, that is interior grade and they will quickly delaminate if wet.

@dlochner 's suggestion to use furniture grade plywood might be a good one but ask about the glue used to make the plywood. If it is an interior grade glue, that won't work.

rpludwig · Jun 17, 2020

Sapele, an inexpensive mahogany sub-specie, best choice hands down. Eze to work with, great grain which POPS when varnished....wouldn't use anything else....and NO to plywood (other than veneered plywood for bulkheads and such)...Sapele example below - DIY galley on our C22...

PaulK · Jun 19, 2020

We worked up bunks out of half inch birch plywood in our forward cabin to replace the SS pipe berths. Trimmed them out with ipé edging. Made sure to epoxycoat all the ply and then varnished everything. Has held up nicely about eight years so far.

Ken Cross · Jun 19, 2020

Don't overlook the option of one of the many types of plastics available out there. There's no maintenance involved with that.

Ken

dlochner · Jun 20, 2020

Fred, the Grampian may be a stick built boat. If that is the case the wood furniture, shelves, settee, cabinets etc are all structural. Plastic components such as Starboard would not be a good choice. These pieces need to be firmly bonded to the hull with epoxy and fiber glass.

If your boat has a fiberglass floor that wraps up into the settees and cabinet, then you have a fiberglass pan and your boat is not stick built. If the wood is tabbed with fiberglass and resin to the hull, then it is stick built and the furniture serves to stiffen and strengthen the hull.

rgranger · Jun 20, 2020

fred1diver said:
what type of plastics are you referring to Ken?

starboard

dLj · Jun 20, 2020

fred1diver said:
DJ, I'm thinking about gutting everything and remaking them, too much wood is rotted and I have a cabinet maker friend who is willing to come help me for a week

So if you are going to try and make the cabinets as fast as possible, using plywood with waterproof glue speeds things up a lot. @rgranger is correct in looking into that. If you can take the time to epoxy encapsulate, then you can use off the shelf plywood finished one side if you want to keep costs down. The real bear is you really want to get every edge with epoxy. The end grain is your biggest concern to get well empregnated with the epoxy.

I make all the parts, put them together to ensure fit and then take them out and epoxy encapsulate. It probably takes about twice the time to build everything, but if you are on a tight budget it can save you a lot of $'s.

Just as a FYI, I do this same technique even on Marine grade plywood construction. I've just found it to be superb Marine grade construction technique.

dj

p.s. just read @rgranger post on stick built vs not. If it's stick built, use Marine grade plywood or waterproof glue ply....

rgranger · Jun 20, 2020

dLj said:
p.s. just read @rgranger post on stick built vs not. If it's stick built, use Marine grade plywood or waterproof glue ply....

That was @dlochner and I agree. Sometimes the bulkheads and settees are doubling as stringers and add stiffness to the boat. You will be able to tell when you pull out the old wood. If it seems stuck to the hull, it is structural and you will want to tab in the new wood.

rgranger · Jun 20, 2020

Here are some pics of a boat I gutted and put new wood into. I used exterior grade plywood from Lowes

Restoration of a Cornado 23'

forums.sailboatowners.com

Bought the boat for $1000, sold it for $6000

dlochner · Jun 20, 2020

Let's get serious about glues and plywood.

Most glues are reasonably water resistant. Even the basic cheap wood glues at the HW store. Let them cure. throw some water on them and they still stick like glue. Now if you are using a starch based glue, like we used in Kindergarten, that's a different story.

For interior furniture on a boat, especially one in Ottawa, there won't be enough moisture to penetrate the plywood, soften the glue and cause it to fail. If the boat should fill with water and stay water logged for a while then the glue might be an issue. Otherwise, not so much.

The most important factors are stability, will the plywood warp or twist? Stability is determined by the number of plies. Cheap exterior sheathing with 3 plies will warp unless it is nailed down every 16 inches. Plywood with 5 or more plies will not warp and twist. More plies and thinner plies yield more stable plywood.

The second big issue is voids and knot holes. Cheap exterior sheathing plywood has knotholes and knotholes hiding in the middle plies. Bad for boat furniture.

The third issue is the outer surfaces. "Birch" Plywood, cabinet grade ply, and marine ply all have well sanded surfaces ready for a light sanding and finish. This makes finishing much easier.

A plywood like this would work.

https://www.lowes.com/pd/Plytanium-15-32-CAT-PS1-09-Square-Structural-Plywood-Pine-Application-as-4-x-8/3010108

Seal all the surfaces with good enamel paint or polyurethane and you'll be fine for your application, your boat, in your location.

If you don't like the appearance of sanded pine and don't want to go to the expense of Birch plywood. Shop for some veneer. and cover the visible surfaces with veneer.

Another option is to laminate a ¼" nicely veneer plywood on to a sanded plywood base. Use thickened epoxy or epoxy and a layer of glass to bond the two boards together. It will be stronger and have a nice surface to stain or finish.

DArcy · Jun 20, 2020

Fred, I just bought some marine ply from KJP Select Hardwood on Bentley, near Huntclub and Merivale. I called around and they had the best price I could find for in stock marine ply. I also bought birch ply from KJP for building furniture in my daughter's room which turned out very well. They have a great selection and good prices.

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