Ply Soup

[gary porter]

There have been several posts and comments lately on the use of plywood
in boatbuilding. In a current post on the longevity of such boats one
person states that my boat will fail from my using LVL stringers. So,
what the heck, last night my wife was busy cooking up dinner and I decided
as long as the bunners were hot I might as well do a little cooking myself.
In pan of water I put a small block,, about 2"cube, of LVL/Versa-lam , a
small square of 1/4" marine ply and one of 1/2". I also threw in a 3"
circular cutout from the cabin of my boat that is coated with epoxy, fiberglass,
epoxy primer and crosslinked polyurethane paint and just for grins a small
block of just plain doug fir. I boiled this mixture for a good 30 minutes with
a lid on top just to add a bit of pressure. The water tainted a bit and the
doug fir swelled considerably but nothing came appart or even hinted of it.
My wife, though not overly happy with me at this point, was making some nice
cookies in the oven so when she was done I transfered the bits and pieces of
my brew to the oven and set it on 300 degrees for and hour. Again nothing
really happened other than the doug fir did check quite a bit. I did not bake
the cutout for fear of making a mess in the oven and having to sleep outside,
its cold up here at this time of the year you know. I also took a chisel to
some LVL and split it to look at the internal grain. The wood separated and
the glue joint held fast. I'm not really sure what if anything all this proves
but I can say that one could boil their boat at least once and bake it for an
hour without fail. I did notice that the fumes gave me a bit of a soar throat
and made my wife , well lets just say less than happy with me. I did check
with Boise and the glue used for the Versa-lam beams is what they call
phenol formaldehyde and isocyanate which comply with ASTM D2559, whatever that
means but it might explain the soar throat. They say its waterproof. I think I
won't burn my boat yet. All ears here,,,,
Gary Porter :D

[ 01-30-2003, 01:26 PM: Message edited by: gary porter ]

[Gresham CA]

Gary,

Thanks for the "Home brew" information. And in a language I can understand.

[George Roberts]

My comment was not that LVL would fail.

My comment was that LVL is not approved for wet/dry cycling. Because boats are subject to wet/dry cycling, the LVL will eventually fail.

There are wood/glue composites that are approved for wet/dry cycles. Some bridges around here have them. They are not the same as those sold for the usual building construction.

1 wet/dry boil cycle is a poor test unless failure occurs..

Feel free to use LVL in your application.

[Dave Wright]

My complements Gary. You have built a fine looking boat. The photos of it are great. You've used a material, LVL, that isn't commonly used in marine applications, but you have had success with it. It's readily available, reasonably priced, easy to work, and has describable and repeatable properties from sample to sample.

Further, you have taken just 30 minutes, roughly the time it takes to post an opinion to a forum, to complete a small and simple test on samples of material used in your boat.

You will get as many opinions on the test as you will on your boat. Some of these opinions may possibly come from folks who haven't had the equivalent experience as you have had with these particular materials. It would be nice to see contrary examples if they exist.

As far as the nature of your test, boil tests were done by plywood rating societies in the past. Yes, it's nice to have multiple test cycles to failure. I've personally tested products and materials to over 100,000 life cycles in a lab setting. Some items require many more cycles. In any case, you can objectively say that samples of material used in your boat have been boiled and baked to dry without any particular evidence of visible degradation. That gives you an indicator of "goodness" very much in excess of that of an opinion.

The boating hobby should be fun, and ideally we should be able to share our successful (and unsuccesful) personal experiences with products and processes. That's how the state of the boating hobby advances. Maybe I'm just cantankerous, but when I see a statement such as:

"the LVL will eventually fail"

I feel compelled to ask for just one related personal example, or perhaps a little good natured explanation. Otherwise the statement just dampens your successful use of the product. Maybe the statement is well intentioned, and the author simply doesn't want you to use a material that he feels will fail more often than not? That's fair. Or perhaps the statement is a variant of

"all materials will eventually fail"

This is as true a statement as "the LVL will eventually fail." But where does that leave us in our quest for reasonable building materials? I worked in a shipyard that built wooden minesweepers in the 1960's. The huge wooden frames were laminated up in big metal jigs and bonded with a hot glue. I think the material was douglas fir; I can't remember the specifics of glue, temperatures, clamping pressure, etc. But, I imagine some of those minesweepers are still in service in third world countries, or maybe sitting in moth balls some where. Yes, all material will eventually fail.

In another design group, and another naval project, we were faced with erosion and corrosion of shipboard components in service in hot tropical seawater. After multiple failures of various materials in succession, we specified commercially pure titanium to build those components. Very expensive yes, and yes, all materials will eventually fail, but those titanium parts survived the life of the ships, and would survive any of us and our progeny in any environment on earth, barring a volcano.

You did just fine Gary, and your boat will be around for a very long time to come.

Apologies for the long spout.

Dave Wright,
Seattle, WA

[gary porter]

Dave , just to keep things all straight and in fairness to everyone ,,the boat you see has doug fir stringers and transom beam. It was because of the difficulty in getting good material on that boat that I started looking at alternatives. I had built a jig for another boat using the LVLs and that promted me to investigate the use of them for the Tolmans.
The boat I have in the shop now has LVL stringers and transom beam and believe that the structural integrity of it is superior. Thanks again
Gary

[NormMessinger]

Okay, I give up. What the heck is LVL?

[Donn]

Laminated Veneer Lumber

[gary porter]

Norm, LVL just stands for Laminated Veneer Lumber.
Versa-lam is Boise's name for an LVL. A 1-3/4" x whatever has something like 18 laminations of 1/10th inch Doug Fir veneers. Unlike plywood all the laminations run parallel to each other lengthwise to the beam. They are also oriented vertically as compared to a glue-lam beam which is layed up horizontal. They are typically used for roof beams, floor beam, etc.
Hope this helps a bit.
Gary

[ 01-30-2003, 06:25 PM: Message edited by: gary porter ]

[TomMcKinney]

Gary-
Thanks for the explanation, from you are saying it sounds like a glue lam beam is made up of short height but wide veners stacked on top of each other while the LVL beam is made tall thin veners staked side by side. If that's not right can you correct me.
thanks
Tom

[gary porter]

Tom, thats pretty close except the gluelams are typically glued up , what looks like, 2x6s, 2x8s etc. etc., If you took a bunch of 2x10s for example and glued them together
face to face you would have a gluelam beam. They stack them quite high depending on the structural load requirements. The versa-lam is pretty much as you have it.
Gary

[George Roberts]

Dave Wright ---

The manufacturers have directions. The direction for the usual LVL include "keep the dry."

I stopped offering "proofs" of my statements a couple years ago.

Feel free to use LVLs where ever you want to. smile.gif

[wolfietuk]

I had a 3' piece pf lvl in my shop yard ( guess it fell off the truck on the way to the dumpster) It was under leaves for over a year, damp with one side against the dirt for over a year. there are also plenty of termites around. When it was moves it was dirty but unhurt, unwarped ect. Please do not confused this with a PSL or paralam. they look like a beam made of osb plywood. They are made of poplar, aspen or whatever fast growing trees are around. All are sealed in a waxy coating and use exterior glue. If kept well sealed I do not see why LVL s wouldnt be a fine boat building product. Giv us a report every year. The manufactures "keep dry" is a cya. I have seen some beams exposed for weeks in a house before it is dryed in. George dont get upset, I think this is one of those taste filling, less great issues.

Rick

[Dave Wright]

George,

I just wanted a little further explanation of your statement. You've got to admit, you didn't give us much to go on. I thought you might have used LVL, or perhaps seen it in a much degraded condition. I would have enjoyed hearing your commentary. Or, how about some info on the laminated woods you mention that are rated for wet/dry service?

Here's a little overview site for LVL (maybe there are some better ones?):

http://www.hochstrate.de/micha/reports/replvl.html

Figure 4 is a photo of LVL boards used as exterior siding on a building. Maybe we should worry that it will fail in a few years, just like the array of "composite" house sidings that have failed over the past few years?

I agree with you, LVL will fail eventually, all materials will fail eventually. If you want a few decades of service, maybe LVL will perform like the laminated wood in the navy minesweepers. If you want a few thousand years of service, use titanium or, better still, use gold.

Which materials do you build in? Do you have any thoughts on how long you like your projects to be functional?

Best regards,
Dave Wright

[George Roberts]

Dave ---

i am an engineer. I can write a sentence or two and make another engineer reconsider his position. He might or might not agree with me.

You are not an engineer. No mater what I write or how much I right. It will never be enough for you to admit you are wrong.

There are stupid questions. How stupid? Think about this. Without any knowledge of the constuction or maintainnce of the boat you would like an answer to the question: Which will fail first the LVL or the boat and when?

If you want to learn, most colleges charge a reasonable amount to show you how. I don't have the time.

(I really should check my spelling or fix my keyboard.)

[Dave Wright]

George,

I'm very sorry to have offended you. I won't do it again.

Best regards,
Dave Wright

[Wild Dingo]

Dave I see from reading that link that this stuff is now manufactured in Australia?... I know its gonna be a big ask but any ideas who? mmmmm maybe Id be best to ask TonyH or Skuthorp?

Great topic by the by Gary... very interesting... mind anything new is interesting... :cool: no no intention of building anything out of it just want to have a gander and a yarn to someone about it... interesting. ;)

[gary porter]

Thanks Rick , Dave, and Shane. I tried to find an Austrailian manufacture but no luck yet.

Dave , Thanks for finding those links, theres a lot of good info there. Your question does not warrant an appology on your part , it was not a stupid question and was much in the keeping with the spirit of this forum. If your question was stupid based on your lack of knowledge of the situation then then statement put forth by that individual was even more stupid. I'm more than confidant that niether the boat nor its stringers will fail in any reasonably expected lifetime. Anyway, enough of that ,,thanks all again..
Gary smile.gif

[pjwalsh]

I've used LVL in house construction and by dint of doing structural work in inclement conditions have seen the effects of wetting/drying on them.

The phenol formaldehyde glue is waterproof, same type of chemistry as has been used in exterior and marine plywood for a very long time (actually it is one our oldest polymer materials, Leo Baekeland's Bakelite is one permutation of this).

The LVL's I have used (13/4" x 14" mostly) are often made of poplar, sometimes douglas fir, and when subjected to the wet a few times they tend to cup quite badly. The stresses imparted by uneven across grain expansion of the laminations must be quite large because even when several LVL are through bolted together with 1/2" bolts they will move even in the immediate area of a fastener. That said, I have never seen a glue line fail.

I would think that if you are using a fir LVL the durability would be no worse than fir plywood. Of course these things are not laminated with the same level of quality as marine ply, and voids may be present to some degree.

What the hell, see how well it works - lots of stranger things have been done - I once found a ping pong table top incorporated into the house of small lobster boat.

[gary porter]

pj, thanks for your info and insight. The LVLs that I'm using are by Boise and are Doug Fir only.
They do expand with moisture as with any wood but are a bit more stable than straight Doug Fir. I'd be hard pressed to ever get much in the way of moisture in the location where I'm using them except for that which one would normally expect from being around or on the water. No direct contact.
Like you say I went for it and feel pretty good with it. Thanks again.
Gary tongue.gif