Prospective Study on Plywood characteristics.

Todd Painton

Todd Painton

Member
This thread is a result of the conversations in other threads which have been addressing the values both economically and structurally of various types of plywood, both BS1088 Marine grade and Non-Marine grade. The method will be a blinded prospective comparson of the plywoods of various manufacturers. I am wanting to study several varieties and will be attempting to get samples from the suppliers but if anyone wants to donate scraps I will be willing to test those as well.

Background: Various plywoods and manufacturers are available for small boat building (<18ft). They vary considerably in cost and characteristics. In addition to expensive grades some non-marine grades have been considered by some to economical alternatives.

Objective: To determine the various characteristics felt important in boat building of the various types of wood. Specifially tested will be Okoume, Baltic Birch, and Meranti. (other varieties may be added provided I receive adequate samples.

Design: Will be a 30 day, blinded, randomized trial. Wood will be subjugated to boil testing, strength to weight ratio, Mildew/rot resistance, cold/heat resistance

Setting: My house :)

Measurements: Thus far include; Boil the wood for 20 minutes, then stick it in the freezer until frozen, boil, freeze, etc. for three of four cycles. Compare the samples for deterioration. Take some samples and put them in the oven at about 150 degrees and compare samples. Mildew test will take wet samples and store them in a cool dark place for one week and then compare outcomes. I am still looking for quantitative ways to measure some of these. Obviously delamination can be compared based on logitudinal measurements from the board edge. Mildew growth might be more difficult if the samples are similar in appearance. Weight differnce change might be worth something but I don't think I have a scale that is sensitive enough, would need to be digital and sensitve to probably the thousandth of a gram. Even that seems crude when measuring mildew mass. I'll look into it. Strenth to weight testing might be hard with small sample size but I'll look into it. Density testing will look at the woods resisance to a weight dropped onto it. And lastly of course is the coaster test. Which piece looks the best as a coaster on my coffee table. (just kidding).

First, will be the search for any tests already done that resemble mine. If anyone knows of any please link them. In the meantime, I'll scour scribd.com and see what I can find.

No commitment on timelines. I am about to move houses and that might throw everything back. I will keep you all posted however.
 
Last edited:
Boil test? I think that is unnecassary, because I won't be hunting hell until it freezes over. Birds just don't decoy well when it is too hot.
 
Search...Google to find plywood manufacturing tests .....possibly ASTM tests...... I think that there is an ASTM standard test for everything up to and even possibly including 4 day old underwear worn by a hunter sitting in a swamp.
 
Search...Google to find plywood manufacturing tests .....possibly ASTM tests...... I think that there is an ASTM standard test for everything up to and even possibly including 4 day old underwear worn by a hunter sitting in a swamp.
Click to expand...
Thanks! Will do.

Boil test is for the texas hunters.
 
I think a search under wood technology would get some info. College students at forestry programs have been studying this stuff since the 40's.
I attended a very good seminar that covered the characteristics of balsa core fiberglass boat hulls in reguards to loss of strength when the core was rotten or wet. Very good info. Ill try to find the papers from it.
I do remember that the loss of strength for wet core was under 25% and that is well within the typical design failure parameters. If experience holds, most wet boats I see are still in service and although heavier are still running.
I think the biggest question is weather or not you are working with a boat where the ply is intended to act as a core for two FRP skins or the wood is the structure and the glass is just for keeping the water off.
Also, dont forget the many(100's ) of plywood skiffs still providing service to watermen that only have latex paint for protection over fir AB plywood.
 
http://www.epoxyworks.com/
Epoxy Works online magazine is from the folks at WEST Systems. They have a few tests done over the years. Some are listed separately from the magazine and others are buried within the various issues.

http://www.westsystem.com/
They have some info but most of it is in the Epoxy Works.

After reading through the other thread I googled "birch plywood boat building" and came up with some interesting hits.

Thread on Boat Design dot Net.
http://www.boatdesign.net/forums/materials/what-best-marine-plywood-23543.html
Based on the comments from one Euro engineer in this thread our Okoume boats have no value in France since Okoume rots easily. Many mentions of Okoume being very rot susceptible across the postings. The one thing that stood out is the use of Finnish and Russian manufactured Birch marine plywoods. Might be hard to find in the US.


http://www.simplicityboats.com/boil.html
A boil test documented for you to review.

http://www.clcboats.com/shoptips/stitch_glue/lauan_plywood.html
CLC opinion on Lauan door skins

http://www.woodenboat.com/forum/showthread.php?t=68001&highlight=birch+plywood
Birch plywood question asked and some good Euro comments about Finnish birch marine plywoods.

http://koti.kapsi.fi/hvartial/white/white.htm
Boat made from Finnish Birch plywood no epoxy just paint. Looks better than most Fir boats half its age.
http://koti.kapsi.fi/hvartial/ Hannu's Boat yard for all your Euro plywood boat needs!

http://www.woodenboat.com/forum/showthread.php?t=5084&highlight=birch+plywood
more WB forum birch blah blah blah, but a couple of posters have built and own non tropical wood boats that are older than most of our duck boats on this forum. There is a 27 year old aircraft birch no epoxy boat mentioned.

http://www.woodenboat.com/forum/showthread.php?t=4421&highlight=birch+plywood
"Proply birch underlayment" boil test results and a follow up with testing okoume and sapele. A must read post for all users of "underlayment" plywoods. Waxed carboard might have an edge on this stuff in the boat building world.
 
http://www.epoxyworks.com/
Epoxy Works online magazine is from the folks at WEST Systems. They have a few tests done over the years. Some are listed separately from the magazine and others are buried within the various issues.

http://www.westsystem.com/
They have some info but most of it is in the Epoxy Works.

After reading through the other thread I googled "birch plywood boat building" and came up with some interesting hits.

Thread on Boat Design dot Net.
http://www.boatdesign.net/...e-plywood-23543.html
Based on the comments from one Euro engineer in this thread our Okoume boats have no value in France since Okoume rots easily. Many mentions of Okoume being very rot susceptible across the postings. The one thing that stood out is the use of Finnish and Russian manufactured Birch marine plywoods. Might be hard to find in the US.


http://www.simplicityboats.com/boil.html
A boil test documented for you to review.

http://www.clcboats.com/...e/lauan_plywood.html
CLC opinion on Lauan door skins

http://www.woodenboat.com/...hlight=birch+plywood
Birch plywood question asked and some good Euro comments about Finnish birch marine plywoods.

http://koti.kapsi.fi/...tial/white/white.htm
Boat made from Finnish Birch plywood no epoxy just paint. Looks better than most Fir boats half its age.
http://koti.kapsi.fi/hvartial/ Hannu's Boat yard for all your Euro plywood boat needs!

http://www.woodenboat.com/...hlight=birch+plywood
more WB forum birch blah blah blah, but a couple of posters have built and own non tropical wood boats that are older than most of our duck boats on this forum. There is a 27 year old aircraft birch no epoxy boat mentioned.

http://www.woodenboat.com/...hlight=birch+plywood
"Proply birch underlayment" boil test results and a follow up with testing okoume and sapele. A must read post for all users of "underlayment" plywoods. Waxed carboard might have an edge on this stuff in the boat building world.
Click to expand...
I found many of those same threads.. The french hate okoume. I think the quote was "Okoume is for building crates" Thanks so much for your efforts. Maybe I could slap together a meta-analysis as a seperate and include my findings. The internet is amazing. The data you dug up would have taken all day in a library 20 years ago. God I'm getting old.
 
Maybe I missed it but what are you using for control ?

Sure would hate to figure out a chi sqared goodness of fit test for this one.

Best,
Harry
 
Ray,
I love the part where the guy lights the row boat on fire after 13 years of service. A proper way to send a boat back to the elements and appropriate, only, for paint/ply building.

I think most guys would be ready to build again after 13 years.
 
If you swing up to Green Bay, I have some Marine Grade Doug Fir and some BS1088 and I believe some Meranti you can have for testing.

How big of a piece do you want?

The other type I would try is CDX, I am curious how it will hold up. I had an old piece in the bottome of my trailer that held up great, then I decided I wanted a tougher bottom, so I replaced it. But just for studying purposes, I left the piece outside. That was over five years ago, still not delamanated. Checked all over the place, but a coat of epoxy or paint may have prevented that.

Another thing to concerned is bending properties. The BS1088 I used for my last boat bent fairly easily, the Doug Fir at the same curve broke. Something you may want to study.
 
Maybe I missed it but what are you using for control ?

Sure would hate to figure out a chi sqared goodness of fit test for this one.

Best,
Harry
Click to expand...

No controls. It's a side by side comparison study. We subjugate all the samples to the same tests and then record the outcomes. Pretty straight forward. No meta-analysis as I have not been able to find any other side by side comparisons of what we are looking for. They are out there, but I'm not going to the library.. Well not yet. I would not include my data with those if I did.. I don't have the measurement sensitivy. It sounded good but it's not realistic. I think the best way to look at this is similar to a hardware review you read on a tech site comparing RAM memory or Graphic CPU's. We are going to take several products and expose them to the same tests and see what happens. Based on that, anyone can make their own conclusions.
 
I have stalled on this. I found out a month or so again that I had a really very potential buyer for my house so I did not want to start a big project if I was going to move. I accepted an offer 2 weeks ago and I am moving to a new house on Feb 10. Once there, I have a ton to do to get the place up to my standards so I see this project probably starting after I stain the deck, which will be when the snow melts and the sun comes out to warm things up. That said, I found out that shipping on Okoume to Neenah, WI is dirt cheap so I will likely, after all this debate and indecision go with Okoume simply because it's suddenly easier to get for me. There really isn't a need to worry about an alternative. This will likely dampen my enthusiasm for pursuing the endeaver.
 
I have stalled on this. I found out a month or so again that I had a really very potential buyer for my house so I did not want to start a big project if I was going to move. I accepted an offer 2 weeks ago and I am moving to a new house on Feb 10. Once there, I have a ton to do to get the place up to my standards so I see this project probably starting after I stain the deck, which will be when the snow melts and the sun comes out to warm things up. That said, I found out that shipping on Okoume to Neenah, WI is dirt cheap so I will likely, after all this debate and indecision go with Okoume simply because it's suddenly easier to get for me. There really isn't a need to worry about an alternative. This will likely dampen my enthusiasm for pursuing the endeaver.
Click to expand...


Thanks Todd for getting back on that. Freight puts marine plywood in reach of everyone. The nice thing about buying BS plywood, is that you know what you are ordering and dont' have to actually take a look at it.
 
Sounds like you are pretty knowledgable about statistical methods. Statistics is the course that damn near flunked me out of grad school. I agree with some of the others that a boil test might be taking it to extremes.

I'm real interested to see what your blind study shows,
Best,
Harry
 
That said, I found out that shipping on Okoume to Neenah, WI is dirt cheap so I will likely, after all this debate and indecision go with Okoume simply because it's suddenly easier to get for me.
Click to expand...
Todd, where are you obtaining you ply from? And what do you consider dirt cheap for shipping? Congrats on the new house and damn it get building already!!! IF you ever do the test that you initially proposed, I would also suggest adding MDO to the equation since that is often used in other areas/countries with great success. I would be happy to bring the beer and the turkey cooker over to help you with the tests.
 
What is dirt cheap and where are you getting it? In my experience, shipping Okume to Wisconsin has never been dirt cheap. In fact when I built my BB3 I drove my suburban to Florida and picked it up for about the same price as shipping it would have been. Of course gas was a little cheaper then.

Also, when you have that plywood tesing party with the deep fried turkey, root beer, etc. - call me, I'll bring something.
 
What is dirt cheap and where are you getting it? In my experience, shipping Okume to Wisconsin has never been dirt cheap. In fact when I built my BB3 I drove my suburban to Florida and picked it up for about the same price as shipping it would have been. Of course gas was a little cheaper then.

Also, when you have that plywood tesing party with the deep fried turkey, root beer, etc. - call me, I'll bring something.
Click to expand...
 
You must log in or register to reply here.
Back
Top