Extreme Marine Plywood Tests

[pipefitter]

I have been reading on this forum for some time about the accepted usage of "marine" rated plywood and a few recent threads got me to thinking of checking my own abusive testing. Not with proper care or maintenence but what the material starts out as. Which is superior or even acceptable. I know there is boil tests etc but I had time to let Ma Nature decide. When I chose my own plywood for my Simmons,I spent the "few" extra dollars for what seemed like a good compromise between "ok" to use and "better value" for the dollar. Here is 2 scraps,left outside on the dirt,in the termite/bug capitol of the US. And to top it off, a slight test of the benefit of the addition of epoxy to the better ply. Kind of like a night and day thing.

http://i99.photobucket.com/albums/l309/tigmaster/P5050027.jpg

Take into consideration that the smaller piece (BS1088 meranti)has atleast 3 more years of exposure than the larger fir piece and sat where it fell and was barely visible amidst the oak leaves it was covered with and was settled into the earth.The exterior marine fir was sitting on the surface amidst the meranti scrap. I purposely left them where they lay just to see what happened. Notice how well preserved the meranti is where the epoxy is. Termites like just about everything but they seemed to have turned their noses up to the wood that is in the meranti. Looks like they had a celebration all around the fir though. I would expect rot to have the same tastes in consumeable woods.

The fir I did use well above waterline,which as a "marine exterior" plywood, is suitable mostly for buildings/homes on the waterfront and not boats,took so much fairing work and epoxy to just match the smooth finish obtained by using the correct BS1088 plywood in the first place,negated the cost difference which wasn't that far off. I only used it because I would have had to order 2 sheets and pay the 65.00 shipping cost. Even then,I would have been better off biting that bullet when adding the hours and extra epoxy and the lack of satisfaction of working the lesser fir. There is no economy in choosing lesser materials for a boat. The meranti scrap is 5 years old.

Here is some BS1088 meranti that was sitting amongst the badly deteriorated fir in the same conditions. This is the underside to the earth. The sunny side up surface looks much the same,just silver colored.

http://i99.photobucket.com/albums/l309/tigmaster/P5050023.jpg

And here is another view and piece of the fir marine ply.

http://i99.photobucket.com/albums/l309/tigmaster/P5050028.jpg

[chuckm]

a thousand words. I thru out a piece of Hyrdo-tek BS 1088 1/2 in ply a year back. Its been in all extremes of humiity and rain, we get @ 80-100 inches a year here. It looks great. I did'nt have a piece of standard DF ply to compare too, but I'm impressed with this Hydro tek line.

[mmd]

Excellent test for marine plys in terrestrial construction. Now take a piece of BS1088 Doug Fir, encapsulate it completely in epoxy with a layer of 'glass impregnated in epoxy on the upper side and lay it out on your jetty/deck in the sun, salt, & rain but away from earth and borers (to simulate a deck structure, which doesn't get continually immersed nor come in contact with terrestrial borers) and see how it wears over the years...

[Art Read]

Lets be fair, Michael, this WAS a fair test of the stereotypical, home-made, half-built, unfinished, un-treated, unpainted, un-covered "project" boat left leaning up against the wood shed under a coat of last year's leaves and pine needles with stagnant water pooling in all the nooks and crannies...

What it has to do with proper boat maintenance, I'm not so sure.

[chuckm]

you know Lithium and other mood stabilizier's acutually work.....

[Popeye]

you can dig 25 year old carrots and phonebooks out of a landfill and they will be looking much like they did on the day they went in

carrots and phonebooks are thus excellent boat building materials

[chuckm]

not always work. It's clear to me, in reading above posts, that electo-shock therapy is the only cure.

[gert]

BS1088 Doug Fir,

where did you find some of that?

serious, I'd buy it

[mmd]

Oops! Sorry - I was hurrying and wasn't paying proper attention to what I typed. I meant APA A-B Marine Grade plywood, not BS1088.

[MarinerKing]

Michael, are you advocating, recommending the use of doug fir ply? As a decking material or other structural uses? With or without fiberglass/dynel sheathing?

Ted

[mmd]

Properly used & applied, yes.

[willmarsh3]

Here's a plywood test.

I used doug fir marine plywood (1/4") on a Shellback dinghy. The dinghy was coated on the outside with West epoxy, Interlux 2 part primer, and one part white brightside polyurethane. I did not apply fiberglass or dynel. It was stored bottoms up in the top tier of a dinghy rack at the marina for over a year where it was exposed to full sunlight and rain. Later it was towed behind a boat for 3 months in various fresh and salt waters as I did my big cruise. No rot or leaks. It did have some bothersome looking checking though. The only maintenance was to periodically sand and repaint the bottom.

[paladin]

My old T'bird and 31 trimaran was made with a-b exterior fir ply and epoxy and it still sails.....I build the internal structure, centerboard/case/rudder etc of Jim Browns personal tri of the same material and it still sails and looks very very good...

[epoxyboy]

you can dig 25 year old carrots and phonebooks out of a landfill and they will be looking much like they did on the day they went in

carrots and phonebooks are thus excellent boat building materials

Yeah right. Put anything in an anaerobic environment like a landfill and it will be reasonably well preserved for years. Leave that carrot or phonebook lying on the ground like this plywood, and if some critter dont eat it first, it be mush after the first rain if not sooner.
Of course the acid test would be to try and eat your well preserved 25yo carrot.
Interesting to see that Meranti isnt as bad as some of the nay sayers would have us believe!

Pete

[pipefitter]

Regardless of the epoxy and glass,the BS1088 is a superior material. The wood species to make it is superior as well. And for 20.00 more per sheet,the surface needs less fairing,epoxy,primer and paint.Fir marine "exterior" is not boatbuilding wood. It's construction lumber for dwellings on the waterfront. Such as dock buildings,stilt houses,soffit material etc. It was one of the first materials I was exposed to in boat building on chop covered sein boats built by fishermen needing a way to work. Even the old timers rated it as no more than construction grade material and the stuff I was exposed to was a heck of alot nicer than whats out there now.

Is there someother point that some would like to make here? The 20bucks you save per sheet ,you will spend 40 on fairing but then again,non-skid hides a multitude of sins. Put some shine on it and get back to me.The sandpaper alone would negate the economy of the lesser woods. Advocating the use of inferior materials on a forum where some poor schmoe has no idea of what fairing work is,where you could of pointed to the common sense of using a "slightly' higher cost material for a better finish overall. What is the end result? "Oh,I am happy with or settling for a workboat finish."

I gave the lesser material a fair shake on my own skiff and there is more work on those 2 sheets than the entire rest of the boat.I used it because my boat stays covered and dry but I sure saw enough that lived at the water fall apart but hey,they were workboats. It's garbage. Read all the posts about knots and voids,sapwood and everyother inclusion of in modern materials. The only reason it is used is because it's cheaper initially. Generations well before me coined the phrase,"you get what you pay for" and somehow the advocates of inferior materials are going to prove this wrong? Why do they bother making better materials?

My point was that the next price grade above the AB fir ply is well worth more as a starting point. Alot of newcomers don't entirely know about proper maintenence.Alot of boats you can't get to all the places to properly maintain them. You can add alot of redundancy by selecting a better base material. So what are the savings on a deck of a decent sized boat? 5-600.00? on a job of 10,000.00 or more,I would call that a shame. But then again,some folks will drive 10 miles to save 1.00 on a box of nails.

[pipefitter]

a thousand words. I thru out a piece of Hyrdo-tek BS 1088 1/2 in ply a year back. Its been in all extremes of humiity and rain, we get @ 80-100 inches a year here. It looks great. I did'nt have a piece of standard DF ply to compare too, but I'm impressed with this Hydro tek line.

The hydro-tek is a much better ply than the fir. I know a fellow here where I buy my hardwoods that uses that and he swears by it. I should have bought that instead of the fir but at the time,I didn't even know they stocked hydro-tek and had already bought the fir.

[pipefitter]

I have been reading on this forum for some time about the accepted usage of "marine" rated plywood and a few recent threads got me to thinking of checking my own abusive testing. Not with proper care or maintenence but what the material starts out as.

I clarified in the opening line, my intentions of the topic. Basically,what the materials are made of. I also used the word "extreme". For those that want to see what is a better material to start with before any coatings are applied. 5 years on the bs1088 meranti vs 2 on the fir.

[pipefitter]

Pipefitter, That's fine.. I understand where you gettin' at...
But trying to get hold of some BS1088 meranti plywood here... It is hard, and it expensive to have it delivered, extra $80.00 per sheet shipping cost ain't saving money...
And nobody in my area will special order it...
So it leave me no choices, but to get a several good sheets of A-C without any voids is simple enough...
That is one reason in marine plywood... Its doesn't have any voids... And somewhat are laminated with five layers, while construction plywoods are three layers...
Both marine and exterior plywoods basically uses same type of glue...
The pirogue in above picture is three years old... Epoxied on inside and outside with fiberglassed bottom... It's fairly strong for what it is..

Boyles,I would use it too if I had to. And that is an open boat and you can get to all areas of it to stop any issues if the need arises. I just wouldn't advocate a professional yard using it to sell the finished product to the general public who may not be totally aware of the maintenence that could possibly be involved. A big yard can get price breaks in shipping and ordering volume. There really is no excuse for an established business to use "ok" materials unless it's insisted on by the client. In other words,low bid or,"I want it as cheap as I can get it". Then by all means,give them what they pay for.

The topic was just to show what was what. Would you not agree that stand alone,without coatings of any kind,that the BS1088 I showed is obviously superior?

I am soon to get some Okume scraps from someone else to subject to the same simple test. It costs more than the meranti but the wood it is made of is said to be "non durable" species whereas the meranti is rated as "moderately durable". When I was shopping for plywood,I wanted to see the difference in real life. I would have settled on pictures like I have shown for comparison. It was for those that are new to boat building that want to see the difference beyond hearsay.

[pipefitter]

Googled for hydro-tek, all I get is.... Hydro-Tek; Manufactures pressure washers and steam cleaners for industrial cleaning applications.....
Are there any other name it goes by?

Try hydro-tec

[pipefitter]

Here's a plywood test.

I used doug fir marine plywood (1/4") on a Shellback dinghy. The dinghy was coated on the outside with West epoxy, Interlux 2 part primer, and one part white brightside polyurethane. I did not apply fiberglass or dynel. It was stored bottoms up in the top tier of a dinghy rack at the marina for over a year where it was exposed to full sunlight and rain. Later it was towed behind a boat for 3 months in various fresh and salt waters as I did my big cruise. No rot or leaks. It did have some bothersome looking checking though. The only maintenance was to periodically sand and repaint the bottom.

The DF marine ply can work. But the BS1088 will not have near the checking issues. Paint will last 2/1 on raw vs. raw situation and just look better overall. The wood that checks alot,will surface swell and shrink alot and it will chip/buckle the edges of the paint when the checks swell back together when it gets wet. The checking will also harbor dirt and mildew which adds to the unsightliness or make it seem more pronounced.

[Caleb Chia]

This test dosnt really simulate marine conditions. How about nailing a few plywood samples to the wharf just below the high tide mark? That way the ply gets a dose of salt water two times a day, simulating really heavy use. That would be a real Extreme Marine Plywood Test.
You also get to test out your fasteners. (does stainless steel really rust?:D :D)

[willmarsh3]

The DF marine ply can work. But the BS1088 will not have near the checking issues. Paint will last 2/1 on raw vs. raw situation and just look better overall. The wood that checks alot,will surface swell and shrink alot and it will chip/buckle the edges of the paint when the checks swell back together when it gets wet. The checking will also harbor dirt and mildew which adds to the unsightliness or make it seem more pronounced.

The reason I used the DF plywood was this was my first boat and I was trying to save a few $$$. I admit this mistake so that others don't make it. This was before the WBF existed. I've used Ocoume on my Elver - no checking. I will avoid DF on any future boats that I build - at least on the exterior surfaces that are exposed to the elements.

With that said, a proper cover to store the boats under when not in use goes a long way to longevity and reduced maintenance. It just has to keep the sun and rain out, and allow air circulation. But I don't think I should advocate this as a substitute for using good materials as it doesn't compensate for the problems caused by voids, sap inclusions, and the use of interior grade materials.

[pipefitter]

The reason I used the DF plywood was this was my first boat and I was trying to save a few $$$. I admit this mistake so that others don't make it. This was before the WBF existed. I've used Ocoume on my Elver - no checking. I will avoid DF on any future boats that I build - at least on the exterior surfaces that are exposed to the elements.

With that said, a proper cover to store the boats under when not in use goes a long way to longevity and reduced maintenance. It just has to keep the sun and rain out, and allow air circulation. But I don't think I should advocate this as a substitute for using good materials as it doesn't compensate for the problems caused by voids, sap inclusions, and the use of interior grade materials.


That was pretty much my point. It wasn't as serious to point any inadequacies of those that had used it. I had used it as well. Just after seeing it firsthand,thought I would share the results amongst those that have the choice and that I didn't save any $ after it was all said and done. I hadn't considered that sandpaper cost 45.00/roll or the difference in cost of 2 extra coats of epoxy and fillers had saved me any $ or not.

There hasn't been much mention of the use of meranti, which is a decently priced material that carries the bs1088 designation. I only ever hear about Okume which is more expensive.I really didn't expect there to be such a great difference between the meranti over the fir but after seeing with my own eyes,there seems to be a great difference. I am also convinced that the reason that there isn't a bs1088 or even a bs6566 D-fir plywood is because it can't be made out of that type of wood.

Overall,I didn't enjoy working with the fir.I did enjoy working with the meranti.For those new to building a boat,I think it would make a difference in the overall experience,just from not being discouraged from all the fairing/sanding.I really didn't expect to ruffle any feathers. It was just an observation.

[pipefitter]

This test dosnt really simulate marine conditions. How about nailing a few plywood samples to the wharf just below the high tide mark? That way the ply gets a dose of salt water two times a day, simulating really heavy use. That would be a real Extreme Marine Plywood Test.
You also get to test out your fasteners. (does stainless steel really rust?:D :D)

It doesn't similate marine conditions but it does depict which is a more suitable food for things that eat wood.I would suspect that the appetites are about the same or that they eat wood for the same benefit to their life cycle and I imagine that dryrot is the same at the waterfront as it is inland.

After what I have seen and experienced,I won't use fir again.If the meranti was ignored by termites, who rarely pass up anything here in the South of wood or even paper, I am shocked that the meranti even survived as it did.

Stainless steel does rust but I work with that often enough(daily) to know how and why. I also know how to keep it from rusting.

[Audasea]

Room for more?

http://i112.photobucket.com/albums/n165/haudsley/Picture239.jpg

http://i112.photobucket.com/albums/n165/haudsley/Picture241.jpg

http://i112.photobucket.com/albums/n165/haudsley/Picture255.jpg

This is scrap luan I used about 2 or 3 years ago as a practice glue up. Half painted with System 3 paint, the other an even split of polyurethane varnish (Interlux Clipper Clear) and clear LPU (System 3 clear). The back was not painted or covered at all. Just epoxy. Globs hanging over the bottom was epoxy that ran off the back and setup. I just left it to find out the affects of UV on epoxy. Rough stuff on the part of the paint is non-skid....a real dirt magnet....you can't scrub it clean.

This has been outside, finish side up, for the past 2 or 3 years. Rain, snow, sun, etc. Cloth on the back is olefin. Tough stuff, but hard to wet out and takes a lot of epoxy to cover. I'm not using it for anything.

All I can say about the test is exposes the danger of rot with sealed and finished plywood on the edges. All edges were coated with epoxy, but that didn't do it. Moisture is getting past. The varnish and clear coats are lifting along the edges. Same is probably true of the paint, but you can't see it. A false sense of security?

As for the Meranti/Fir issue. I've never used Meranti, but have used Fir. It checked and I'm sure moisture is getting in and rot is at work, just like in these photos. If I was after longevity, I wouldn't use fir. You make your own choice.

[brad9798]

My best plywood test is my 1964 Chris Craft, 35' aft-cabin ...

She has had proper maintenance throughout her life ... and about 80% of her ORIGINAL hull is still there!

Good stuff. IMO. :)

[brad9798]

Nothing recent ... let me find something ...

[NuSKcalB]

Every boat I have been involved in over the last few years has used DF plywood - mostly on decks, sometimes in cabinetry and at least one had 100% DF construction.

In EVERY case, the results (in varying degrees of seriousness) of using this inferior material have been the same. This wood is not suitable for boatbuilding. No matter how it is prepared, treated, covered or whatever, in the marine environment, it fails. This could be from simple checking through to full delamination and rot.

Even boards used as berth supports, in my 1970's Folkboat (which are not exposed to 'direct' UV or moisture/water exposure/ingress) are showing signs of checking and laminate breakaway on the edges.

Every DF underlayed deck I have had the pleasure of working on has either crumbled away in parts of come away in separate laminate sheets!

The boat I mentioned that was 100% DF plywood - a simple skiff - had not had a very hard life but the inferior strength of this poor material choice, was very evident when the bronze 2 bow eyes (heavily backed) had pulled out completely whilst at her mooring/dock.

I should add that I didn't build these boats and having seen the unsuitability of this material, though 'possibly tempting' for fiscal/availability reasons, I wouldn't ever use this material for anything that I was going to put into the water. It really is a false economy and I have to question anyone in an 'official/proffessional' capacity, that advocates its use over 'standardized' materials, when they are available, or suggests that DFP in an acceptable and therefore suitable, material.

I live In Nova Scotia, supply/demand makes much of the materials that I need/want, harder (i.e expensive) to come by, however, if I am putting my life and that of my family, friends etc. on the line, in one of my boats I know what I'll be spending my money on. (Yes Ted, the Deck is coming off!)

Your mileage may vary........

NuS

[pipefitter]

The thread wasn't to disapprove anyone elses choices. It was to show a basic difference.The initial basic difference of materials. I am sure they could be made to be more environmentally sound as I am sure some have but I still feel it is false economy. It was questions I had when choosing materials. Moderately durable wood species. Meranti is classed as moderately durable along with DF. But I found that the DF used in plywood is not really moderately durable in plywood form. I thought that some would like to know about the meranti vs the DF or new builders not to be afraid of it just because it doesn't cost as much as okume. I know what I would choose and will choose from now on. Anyone else that can see the benefit of the minor evidence of the pictures posted,will have room for more consideration when choosing materials for their own boats or not.I thought it was a decent time study.

[Nick C]

I saw a dory for sale on a web site, it was a 1985, was built with doug fir and had recently had a been more or less refurbished. I know they build those things out of doug fir and as you can see so far it has only lasted 21 years. That's with a paint job, not encapsulation!!

I am curious, how do you know you really use douglas fir for your experiment? Many places will bait and switch on that product.

Here's another experiment for you, ,try the same thing with some mahogany ( I don't know which flavor). I've hear mahogany actually benefits from being in salt water and lasts longer.

Say, what do you do for a boat with termites?

[pipefitter]

I saw a dory for sale on a web site, it was a 1985, was built with doug fir and had recently had a been more or less refurbished. I know they build those things out of doug fir and as you can see so far it has only lasted 21 years. That's with a paint job, not encapsulation!!

I am curious, how do you know you really use douglas fir for your experiment? Many places will bait and switch on that product.

Here's another experiment for you, ,try the same thing with some mahogany ( I don't know which flavor). I've hear mahogany actually benefits from being in salt water and lasts longer.

Say, what do you do for a boat with termites?

Here you go. I well know what DF is. If by some remote chance there is a twin that they use and label as such, then that would be yet another thing to consider could happen to anyone buying it.Here is a piece from the same sheet that the rotted wood came from.

http://i99.photobucket.com/albums/l309/tigmaster/P5080053.jpg

I bought DF marine exterior ply. It smells the same as the DF I used to frame houses with out west and the boats i worked on years ago,although the wood in the ply doesn't look as good as the framing lumber. I also acknowledged that the DF ply isn't the same as the older stuff which was more reddish colored and had tighter grain and more plies. The newer DF marine exterior ply is crap,especially the thinner plywood now compared to what used to be available.
Wasn't just termites in the DF ply. There was also dry rot,roots of small plants and some other fungus looking stuff and mold. The ply also delaminated before the bugs and such ate it whereas the meranti did not. The meranti is obviously a more stable lumber species to build plywood from.
Termites? Same as a house I suppose. Tent it and give them a dose of methyl bromide gas.
I am getting a scrap of okume tomorrow just for the heck of it.

Build all the boats you want from DF ply today and compare the sanding and epoxy needed to bring it to the same level of finish as the meranti. Even if it lasted as long as the bs1088 materials,I still wouldn't use it. Better yet,since all the exterior plies use the same glue,save even more money and use cdx.It has about the same exposure life as the Df give or take a few months and about the same amount of knots on the bad side.Another point with being that both sides of the meranti were good,one is able to use more of the irregular drops.