marine grade plywood or substitute

Hey does anyone know a good place to buy marine grade plywood or the good quality cabinet plywood around the pittsburgh, pa area? Even some good websites to order from would be good. I need to make a front splitter/undertray for the miata and a new dash for a 66' Elan S2. Thanks Paul

Homedepot/lowes/ any other lumber yard of choice can order it for you, but it will cost. May be a minimum order.

Good Luck.

Check with a boat yard (if possible) or other building supplies as some tubs require the marine grade under

Go to a dealer and ask them.

FWIW, there are (for the most part) two thicknesses used. Most use the industry standard, 1/2 inch, but the top brands (I know Cobalt and Lund for sure, and I think ChrisCraft as well) use 3/4 inch.

This is just some useless information. I highly doubt that you would need the 3/4 inch.

Marine grade plywood and good quality cabinet plywood are not interchangeable. Which are you looking for?

Decent cabinet quality birch plywood can be purchased from any lumber yard, including the big box stores. Although, they will stock material with fewer laminations (plys) (because it is cheaper), which makes it less dimensionally stable. It will also be made of narrow width veneers, so the finished surface will have multiple grain laps in it.

High quality cabinet plywood will have more plys, and be rotary cut so that the grain is prettier. It can also be purchased bookmatched (very expensive). This will not be available in your local lumber yard- it will be special ordered. You probably can't even order it from Lowes.

Marine plywood is different. It uses water resistant glues and treatments for better performance in conditions exposed to water. It is used frequently for skeletal structures for fiberglass boats, etc. Scraps could be found cheap from boat manufacturers. Again, you won't find it at your local lumber yard, and the box stores will give you a blank stare if you even ask. They will probably try to sell you pressure treated plywood. (not even close).

If I were you, I'd use 1/2" locally available birch ply for the dash- plenty stable enough, and it won't really be exposed to much moisture. If you don't like the look, you can laminate a veneer on top of it, like book matched koa, or other beautiful wood.

For the splitter/ undertray I'd consider pressure treated, or build it out of fiberglass with no wood backing.

Both of these would be locally available.

There is also baltic plywood, which is good stuff. Not easy to find, but woodworking stores or shops may stock it.

http://www.homesteadhardwoods.com/
I get mine from here.
I have gotten mahogany, curly maple and marine grade douglas fir plywood there. They have much more.
Located just south of Sandusky, Ohio (Cedar Point area) which would not make for an impossible days drive. Easy access from Ohio Turnpike.

As an interesting side note, the owner built his own "field of dreams" in his backyard. Out in the outskirts of an obscure small town, at the dead end of a country road, the guy built his own lighted baseball diamond. Pictures:
http://www.homesteadhardwoods.com/map.html

SVreX makes a good point(s) here. Also remember that a HUGE part of the reason boat manufacturers use the plywood they do is that it won't warp in the sun. I think would also be a very important consideration for a dashboard.

SVreX wrote: Marine grade plywood and good quality cabinet plywood are not interchangeable. Which are you looking for? Decent cabinet quality birch plywood can be purchased from any lumber yard, including the big box stores. Although, they will stock material with fewer laminations (plys) (because it is cheaper), which makes it less dimensionally stable. It will also be made of narrow width veneers, so the finished surface will have multiple grain laps in it. High quality cabinet plywood will have more plys, and be rotary cut so that the grain is prettier. It can also be purchased bookmatched (very expensive). This will not be available in your local lumber yard- it will be special ordered. You probably can't even order it from Lowes. Marine plywood is different. It uses water resistant glues and treatments for better performance in conditions exposed to water. It is used frequently for skeletal structures for fiberglass boats, etc. Scraps could be found cheap from boat manufacturers. Again, you won't find it at your local lumber yard, and the box stores will give you a blank stare if you even ask. They will probably try to sell you pressure treated plywood. (not even close). If I were you, I'd use 1/2" locally available birch ply for the dash- plenty stable enough, and it won't really be exposed to much moisture. If you don't like the look, you can laminate a veneer on top of it, like book matched koa, or other beautiful wood. For the splitter/ undertray I'd consider pressure treated, or build it out of fiberglass with no wood backing. Both of these would be locally available.

Good point on the warpage.

Pressure treated plywood will warp like crazy.

Birch won't warp too badly.

It's about moisture content. P/T plywood is pumped FULL of moisture. Birch is pretty dry. Construction grade ply

Good point on the warpage.

Pressure treated plywood will warp like crazy.

Birch won't warp too badly.

It's about moisture content. P/T plywood is pumped FULL of moisture. Birch is pretty dry. Construction grade plywoods are not too good either.

Also the Baltic (birch) is Normally available in 5'x5' sheets. That can be good or bad depending on what you are doing with it. Im a carpenter by trade, and that always weirds me out lol so used to 4x8

So help me out. I need to replace the plywood sides of a homemade utility trailer. I priced marine plywood and its too expensive. PT is priced better, but don't want that if it warps so badly. I didn't know it did. How about exterior plywood with a good few coats of paint?

SVreX wrote: Marine grade plywood and good quality cabinet plywood are not interchangeable. Which are you looking for? If I were you, I'd use 1/2" locally available birch ply for the dash- plenty stable enough, and it won't really be exposed to much moisture. If you don't like the look, you can laminate a veneer on top of it, like book matched koa, or other beautiful wood. For the splitter/ undertray I'd consider pressure treated, or build it out of fiberglass with no wood backing. Both of these would be locally available.

Thanks SVrex, I will likely try the birch for the dash. It doesn't need to be really pretty, just not ugly. It will be in a race car, so its really function over form.

I may just layup a fiberglass splitter and undertray. It may prove to be the lightest and easiest overall. I have a notion to try and add a slight diffuser with tunels that channel the air towads the front wheel wells for the extra low pressure area to help evacuate the air.

Ahhhh now if this blessed snow would just STOP falling so I could get to my garage!

Thanks Paul

Army grade will do just as well, but stay away from the Air Force grade stuff.

spitfirebill wrote: So help me out. I need to replace the plywood sides of a homemade utility trailer. I priced marine plywood and its too expensive. PT is priced better, but don't want that if it warps so badly. I didn't know it did. How about exterior plywood with a good few coats of paint?

No. For a homemade utility trailer stick to the PT. It will resist rot better, and the exterior plywood will warp just as badly.

A little bit of warpage on a homemade utility trailer is tolerable. A little bit of warpage on a restoration dashboard is not.

Just support the top edge by attaching it to a small piece of angle, or perhaps a 2x3 or a 2x2 (depending on the size of the trailer). Should work great.

Dang SVreX you are bringing the Plywood tech to this thread.

I bought some nice 23/32nds Cabinet grade plywood at my local HD. They had it on special for ~$23. I'm using it to make a bar top and cut it into 1.5" wide strips that i will face glue, so ~30 strips per sheet. I was quite impressed with the quality of the wood. It was 5 ply so could have been more plys, howver the plys had minimal voids throughout the piece, no delamination and the top and bottom face layers were smooth and radial cut so they had a minimal amount of seams. Overall it was some of the nicest plywood I've worked with.

I think on my MG I'm going to build the spliter bottom and diffuser out of shower surround board (melamine I think). It's ~1/4" thick and quite dense, and the water stability should be high. As a bonus you can get it with that rediculous 1970's blue and off white flower pattern. Why anyone would put that into a house is beyond me, but I think on the underside of my car it will make a statement. Probably something to the effect of "I feel Pretty". Although it's ~$15 a sheet, so it is more expensive than 1/2" pressure treated, and it will need more support structure. I'm more likely to really end up with .040 aluminum with a 1/2" square steel frame, as it's $60 a sheet and is really the right way to do it.

My Work & Play trailer has 1.25 thick 15 ply marine plywood. It soild as a rock.

Good lord I'd hope so. Thats some serious wood.

My Wooden Boat does not have plywood that thick. 1954 Custom 22 ft Hardtop Cedar Planks White Oak Stringers Phillippine Mahogany Douglas Fir Marine Plywood roofs. Still in restoration indoors but we are now past the De-struction phase and into the Con-struction. <img src="" />

If you want the best quality, I would probably avoid the big box stores. I bought 3/4 oak plywood from Home Depot for a recent project, but it wasn't completely true and caused some problems during construction - not unworkable, but created problems to solve.

In the Pittsburgh area, Brookside Lumber in Bethel Park is excellent (http://www.brooksidelumber.com/brookside.html?template=brookside). They have lots of quality wood and friendly, helfpful people that will answer all your questions. I don't have any personal experience with Irwin Builiders Supply in North Huntingdon, but I've been told they also have very high quality products (http://ibspa.com/). West Elizabeth Lumber may also be an option.

SVreX wrote:

spitfirebill wrote: So help me out. I need to replace the plywood sides of a homemade utility trailer. I priced marine plywood and its too expensive. PT is priced better, but don't want that if it warps so badly. I didn't know it did. How about exterior plywood with a good few coats of paint?

No. For a homemade utility trailer stick to the PT. It will resist rot better, and the exterior plywood will warp just as badly. A little bit of warpage on a homemade utility trailer is tolerable. A little bit of warpage on a restoration dashboard is not. Just support the top edge by attaching it to a small piece of angle, or perhaps a 2x3 or a 2x2 (depending on the size of the trailer). Should work great.

That's almost exactly what I had intended to do. Last time I was in Home Despot though the plywood looked like crap. 3/4" looks too thick. 1/2" looks too thin. I feel like Goldilocks.

haus356 wrote: In the Pittsburgh area, Brookside Lumber in Bethel Park is excellent (http://www.brooksidelumber.com/brookside.html?template=brookside). They have lots of quality wood and friendly, helfpful people that will answer all your questions. I don't have any personal experience with Irwin Builiders Supply in North Huntingdon, but I've been told they also have very high quality products (http://ibspa.com/). West Elizabeth Lumber may also be an option.

Thanks Haus, I live in Elizabeth Twp, so Elizabeth Lumber is 5 minutes away, and grew up a 10 minutes from Brookside(a very good place, plus have contractor lunches for free on Wednesdays in the summer!). I'll check them both.

nocones wrote: Dang SVreX you are bringing the Plywood tech to this thread.

33 years worth of experience working with the stuff plus 5 years technical training on the subject give me nothing more to offer than a bit of advice on PT plywood.

Hope it serves someone well.

For the splitter, why not use 1/2'' foam and fiberglass it? Its alot lighter then plywood.

For the marine grade plywood, in pittsburgh, it really is easy to find, call any of the boat yards around you and they'll either sell it, or know where to buy it at.

Andrew

For really heavy duty you want the big box, but not the box store, as in the side walls of a semi trailer or rental truck. Typical is 3/4-5/4 of marine ply with a 1/8" layer of fiberglass bonded on as the outside layer.

Cheap too, if you have a cordless saw....