The wood used to make your boat , a question about the wood.

[oldsparkey]

I was answering a question a builder had on Matt's web site and decided it was better to bring it over here. Especially since we do kick things around a little more over here , actually we beat them to death at times. :lol:

Here is part of my answer over there........
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I am a boat builder with the idea of making a sandwich , the filling is just that , the filling or what you want to see or snack on.

The filing ( wood) is what determines the shape of the boat and in our case the looks of the craft and the fiberglass (Bread) is what gives it the body or strength.
Epoxyed plywood will increase up to 4 times in strength , depending on the saturation of it but it is the fiberglass that offers all of the protection and the additional strength to a wood boat.

Look at it this way , epoxy saturate the wood , what are you doing ? You are making wood into a epoxy saturated item. Now you add the glass , what are you doing , you are epoxy saturating the glass , the same thing you did to the wood.

What do you end up with , an epoxy saturated wood boat with an epoxy saturated fiberglass skin over it or an all epoxy boat that looks like wood. Very Happy
A sandwich where all you can see is the filling in it.:lol:

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I posted this in the SERIOUS SECTION to keep it that way...

The question I have is this.

1. Has anyone taken the expensive wood , cut it into a 1 inch by 24 inch strip and then done the same thing with some $9.95 Luann , epoxyed saturated them and tested them to see which broke 1st.

2. To make it a fair test using the same size pieces of wood tested there breaking point without any epoxy on the strips.

I know a plain strip of wood will break way before the epoxyed one , just wondering what the difference is when using the more expensive wood since most of us want to keep the cost down when making a boat.

When you can get 4 sheets for the price of one of the others , this is not rocket science.

Kit boats are the exception , they use the expensive wood because that is what the general public wants or thinks they want. Plus the designer/kit maker has to worry about liability and doesn't want any mismatched wood in there kits.

Some home builders actually go out of there way to find some panels that are not normal to make there boats with , it is what they want and it is definetly there boat the way they wanted it. The ones I have seen are works of art and definetly stand out demanding to be looked at and enjoyed.

Chuck.

 

[Kayak Jack]

I've never done the test. Likely a similar result. Until you get to a void, plug, or patch in the economy woods.

Using careful selection to get precisely what piece of cheaper wood to use, against a selection from anywhere in any sheet of the expensive wood, you should get similar results.

 

[FlaMike]

My main concern is not so much using a different type of wood, as it is a different thickness.

For my UJ designed Pirogue, the thickness seems to be more a question of weight, than anything else. The way it is designed, it invites "customization" by the builder. Even so, being a first-time builder, I ran every change I wanted to make past Uncle John, first.

Now with one of Matt's designs, where you have 6 to 8 panels making up a hull, (as opposed to UJ's 3,) I'd think the design would be a little "tighter," less open to too much re-thinking by me.

Since the design I'm about to start on calls for 4 mm ply, with 6 oz fg cloth on the outside, and 4 oz on the inside, I figured on locating 4mm Okoume.

Now, would I be taking a "risk" using Luan, instead? And is it produced in 4 mm?

What got me to asking about that was being told that for this design, the 1/4" exterior would really be thicker than needed, and using 1/8" luan (3 ply?) might save weight, but not be as strong as the 4mm marine ply.

To tell the truth, it may come down to what I can find around here. So far, I've only seen 1/4" exterior CDX available. I'll be making some phone calls Monday, to see what I can find.

The good news is that I'm still tied up in court (as a juror) for one more week, and the design probably won't be released until about then, as well. So, I've got a little time before I actually commit to one kind of wood or another.

And I am still open as to what I eventually do, provided I can find something suitable.

Mike S.
Spring Hill, FL

 

[JEM]

Since the design I'm about to start on calls for 4 mm ply, with 6 oz fg cloth on the outside, and 4 oz on the inside

not sure where you got that from. Perhaps you're thinking about our conversation about the fiberglass for the deck.

Hull: 6-ounce inside and out.
Deck: Can use 4-ounce inside and out.

 

[oldsparkey]

It is best to follow the designers suggested way of doing it. When the boat is done you will have a working knowledge of the process and then can deviate from it , to customize it the way you want the boat.

I always tell folks to make one 1st , then decide what you want to do differently with the next one , if anything. If you have questions then contact the designer about them. He knows the boat better then anyone.

You have made a Pirogue , all the other boats are the same , nothing more the some wood , epoxy , fiberglass and a little cussing in the process.

It just depends on what you want and how you want it , plain and simple. The key word here is ......... YOU.

Matt pulls his hair out everytime I build one we have been talking about , in fact he has gotten so he does not even send me the instructions , just the plans.
Simple reason , he knows I will build it the best way possible and add some thoughts of my own to it ( after checking with Matt) . That just comes from understanding boats and after building a couple of them. Besides Matt looks good with most of his hair missing :lol: :lol: :lol: and I like his designs.

Chuck.

 

[Kayak Jack]

Mike,

You will probably receive different answers to your question about risk. In my opinion, yes, you would be adding a risk factor. Others my find it acceptable.

I still consider myself only a medium skilled builder. I do not want to screw around trying to outguess the professional plywood manufacturers on where they hid voids (missing wood), patches, and other inconsistencies. I want a good, reliable piece of material with which to work. They'll have a broken interior and cover it with a thin veneer that looks good. I consider that to be shoddy merchandise. Just my opinion.

With a multi panel hull, the 4mm glassed inside and out, you will have a much more robust hull ht an in the pirogue. It is a fully monocoque construction. The strength is in the skin, rather than in a frame that is sheathed over like a house. It is an inverted arch; arches are self-supporting.

 

[FlaMike]

Hull: 6-ounce inside and out.
Deck: Can use 4-ounce inside and out.

Yes, I figured that out after I posted that 6 oz. outside, 4 oz. inside remark, and then re-read the email where you said I could use the 6 oz. stuff I have on-hand, and add 12 yards of the 4 oz, 30 in. wide.

You were quite clear enough, Matt. I was just thicker than usual.

As for exactly what I'll use, it's looking more and more like it will have to be whatever I can find. I tried the "local.com" search, and a few others. The only source I've turned up so far is Triton Marine in Homosassa, their web site says they have "Okumi marine plywood."

In the early AM, I'll crack open the old-fashioned Yellow Pages (if I can find the darned thing) and conduct a "manual search."

Mike S.
Spring Hill, FL

 

[FlaMike]

Update on my plywood search.

About 40 miles North of me, I found a source that normally carries 4mm Okhume ply, but he says he likely won't have it on-hand until December. (Not Acceptable!)

A bit further, about 60 some-odd miles, I found a place that has it, but the thinnest is 3/8". He thinks he can get some in for me and is going to email me when he finds out. He's sending me a price quote and availability date. His price for that 3/8" stuff is $65 a sheet, no idea what the thinner sheets will be, I asked about 4mm, he's looking for 3/16". Close enough, I think.

But the closer supplier did suggest something he does have, something called Ozigo. He says it isn't actually a "marine grade" ply, but with the epoxy building technique, it should do fine. Here is all I could find out about it, on-line:

Ozigo, aka: Dacryodes buettneri

Density 0.50 to 0.65
Medium-hard wood.
Used for plywood, inside joinery.
From Africa : Guinée, Gabon

Looks like this:

I'm thinking this is something that I might consider applying a water-based stain to. Oh yes, this would be $36 a sheet.

Any thoughts on this?

And just for the record, I'm NOT done looking just yet.

Mike S.
Spring Hill, FL

 

[oldsparkey]

It is my understanding the only difference between normal plywood and marine plywood is the glue they use.

" Plywood for indoor use generally uses the less expensive urea-formaldehyde glue which has limited water resistance, while outdoor and marine grade plywood are designed to withstand rot, and use a water resistant phenol-formaldehyde glue to prevent delamination and to retain strength in high humidity. "

The above was taken from a plywood manufacture explain the difference between the two. Which leads me to this question..............

If you epoxy saturate it and then glass it ... What would be the difference since both the epoxy and fiberglass waterproofs the wood ? One seals it and one covers it protecting the wood.

An good example is that the US Government pays $600.00 for a toilet and I get one for $75.00 , they both do the same thing and probably are the same one.

As I said , it is your boat do it the way you want and use the material which you think is the best or desire to use. Choices , they make this world turn on its axis everyday.

Chuck.
PS. Bad pun here , it is me stirring the pot. :lol: :lol: :lol:

 

[JEM]

look at the plies. The best quality will have even thickness plies. For 4mm, you'll most likely have 3 plies.

 

[swamprat]

Triton marine is who I went thru for my Okume on my last two builds. That was when I lived a bit closer than Naples.

 

[hairymick]

Mate,

ask the bloke if it is three ply or just two very thin veneers with some sort of filler in between.

A lot of the inferior, thin ply just has this filler and is not genuine 3 ply.

Marine Ply has three layers of ply and the glue bonding them is way superior .

A good boat can be built using the two outer veneers stuff but it is harder to work with. It will also absorb more moisture from the atmosphere if stored for long and can warp ( before it is used.)

Most of my boats have been built using this stuff and the problems dealing with warped ply are way more trouble than the the price of them is worth. I won't be using it anymore.

 

[FlaMike]

Many thanks, guys!

I'm waiting for an email from a shop in Lakeland about what he calls 3/16" Okhume. (All he had was 3/8" in stock.)

Now I know what to ask the man at Triton about that Ozigo plywood. And I will look at it before buying any. I think if it's only 2 ply with filler, I'll pass on it. I'm not certain, but I think he did say it was a 3 ply material. I'll also look for a dark glue line between the plys.

And I'll expand my search range out to say, 150 miles. (Man, I hate road trips!)

Mike S.
Spring Hill, FL

 

[JEM]

-3 even plies
-dark glue lines
-little to no voids

Those criteria will get you some nice wood. Ask if you can get a sample piece mailed. Probably not, but it doesn't hurt to ask.