Clicky

Plwood

funbun

Well-Known Member
Sep 11, 2007
214
1
Alabama
I went to Lowe's earlier this week. They had 1/4 inch hardwood plywood -- three layers of oak. Would this be good for a canoe hull?
 

oldsparkey

Well-Known Member
Aug 25, 2003
10,409
109
78
Central , Florida
www.southernpaddler.com
Might make a heavy boat being Oak but since I have never used it I am just guessing. On the other hand there have been a lot of boats made from Oak. Some of the experts on here would be able to offer more information.

Personally if the wood has a good grain to it and very few voids I use it , never paid any attention to what it was. Now remember I am not a sophisticated boat builder , I just make them the way I like them.

Chuck.
 

Steve

Well-Known Member
SHeena and I used oak ply on her boat build. . . avoid it if you can. . . the boat was heavy and like Matt said soaked up lots of epoxy. . . with the epoxy, the checking was minimal but it had started before the saturation coat. . .Does make a good lookin' boat tho'
 

gbinga

Well-Known Member
Nov 7, 2008
736
2
Hoschton, GA
Since you are shopping at Lowes I will assume you are trying to keep the price moderate, since they aren't going to have any high class marine plywood in there.

That being the case, see if they have a "premium underlayment" called "Ultraply XL"

Should be about twenty dollars per sheet. Will look like good clear luan on the good side, and will be a swirly grained blond looking wood on the back side. What I bought was uniform, relatively light, remarkably void free. Supposedly with waterPROOF glues, whereas the regular 10-12 dollar luan says water RESISTANT.

When I bought it (at a Lowes here in Georgia) they had it on the back wall in a bin by itself, not in the aisle with the rest of the plywood.

Now you can absolutely get better plywood than that, and a lot of the guys will tell you that you should, and they could be right. But if your budget or your own personal judgement says moderately priced plywood is the way to go, I can tell you that this stuff seems to have worked well for me. I feel confident that it is the best product you will get in a Lowes or a Home Depot, anyhow.

George
 

tx river rat

Well-Known Member
Feb 23, 2007
3,043
2
Waco Tx
I am going to add a little note to this,I have built 9 boats 8 out of laun and never had a problem ,and Chuck will testify that I use the heck out of my boats and they are not babied.
One note and I think this is important with any ply but the cheaper ply especially MAKE SURE THE PLY IS COMPLETELY COVERED AND ENCAPULATED IN GLASS.
Ron

Mine have been built from the 10.00 a sheet stuff
 

oldsparkey

Well-Known Member
Aug 25, 2003
10,409
109
78
Central , Florida
www.southernpaddler.com
All but two of my boats have been made from the $9.95 a sheet Luann ( 1/8th inch thick) and they are still being used and in as good of shape as when I made them , the numbers ... 8 out of 10 boats. The two without Luann were kits I purchased and the wood was with the kit. The lightest boat is 30 pounds and the heaviest is 40.
I epoxy saturate the wood and then glass it for protection.

Chuck.
 

bluegrasslover

Well-Known Member
Feb 18, 2009
202
0
52
Willow Springs, NC
oldsparkey said:
I epoxy saturate the wood and then glass it for protection.
Chuck,
I'm using the same luan. Do you saturate the inside and outside or just one side? I did the outside but wasn't sure if I needed to do the inside as well. On the bottom, one half was from a darker sheet and man did it soak up the epoxy. You could barely tell I had applied anything at all. The bottom is very distinctively 2 different colors but since I'll be either using graphite or painting the bottom it doesn't really matter.
 

oldsparkey

Well-Known Member
Aug 25, 2003
10,409
109
78
Central , Florida
www.southernpaddler.com
I saturate both sides , besides adding some strength to the wood it offers the epoxy when you glass it something extra to bond to. Especially since the saturation coat has soaked into the wood.

Using the Luann when cutting out the panels you need to pay attention to which side of the wood you are using and when doing one side of the boat have the side of the wood you want facing out corresponding to the way the panels are cut from it , the same with the other side of the boat.
In plain language the outside ( which ever side you like the best) of the Luann will be on the outside of the hull when the panels are cut out.

Chuck.
 

Steve

Well-Known Member
oldsparkey said:
I saturate both sides , besides adding some strength to the wood it offers the epoxy when you glass it something extra to bond to. Especially since the saturation coat has soaked into the wood. . .
I use epoxy on my furniture projects, especially when I am using mortise and tenon joinery where I spread glue inside of the mortise and on the tenon, letting the resin soak in, then after a light hit on hte sandin' I'll apply the glue up expoxy to the mortise and then clamp things together. . . It makes it hard to fit the joints sometimes as things get mighty tight but that saturation coat really helps the epoxy hold things permanently. . . I have never had a joint I put together like that come apart on me. . . Even when I use cherry, where it LOVES to gap itself at the joints.
 

gbinga

Well-Known Member
Nov 7, 2008
736
2
Hoschton, GA
tx river rat said:
I am going to add a little note to this,I have built 9 boats 8 out of laun and never had a problem ,and Chuck will testify that I use the heck out of my boats and they are not babied.
One note and I think this is important with any ply but the cheaper ply especially MAKE SURE THE PLY IS COMPLETELY COVERED AND ENCAPULATED IN GLASS.
Ron

Mine have been built from the 10.00 a sheet stuff
I wouldn't hesitate to use the 10.00 per sheet, if I could find a couple of good clean sheets, which you usually can if you are patient and flip through the stack and maybe go to a couple of different stores if you have to. Lots of guys that build more boats than me use it and have great results.

I just figured that whether I spent $20 on plywood or whether I spent $40 on plywood was not a big deal considering the cost of epoxy and glass, which is going to dwarf the plywood cost either way. And the "ultraply" seemed cleaner, straighter, and claimed to be waterproof, which I feel is meaningful even if you encapsulate.

But if you don't see the Ultraply, and they do have good clean straight luan, then go for it.

GBinGA
 

Steve

Well-Known Member
GB, the thing about the waterproof/water resistant bit. . . actually all the makers of ply are using basically the same glues, and the quality of the glue in our cases to be total honest, while important for the plywood initially, (some of the guys may disagree with me on this, but it is how I see it) once the boat is given a GOOD saturation coat before applying the glass, the epoxy basically overrides the glue already there. And the GOOD saturation coat helps in the prevention of dry rot later on down the road, if the boat is cared for properly. So, the waterproof vs water resistant, in my book anyway, is not an issue. A thorough saturation coat , inside and out, will be the answer for all ply. . . cheap or expensive.
 

Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
168
84
Okemos / East Lansing Michigan
Steve said:
. . . actually all the makers of ply are using basically the same glues, ... and the epoxy basically overrides the glue already there. ... A thorough saturation coat , inside and out, will be the answer for all ply. . . cheap or expensive.
Steve, the manufacturers of plywood - so far, in all countries where its made - have definite standards of manufacture. They contradict your statements here. There are definitely different types and grades of wood and glues, designed for different uses and applications.

Builders can choose to flaunt - or use - those manufacturer standards and recommendations, and that may, or may not, work for individual builders.
 

oldsparkey

Well-Known Member
Aug 25, 2003
10,409
109
78
Central , Florida
www.southernpaddler.com
Steve said:
(some of the guys may disagree with me on this, but it is how I see it) once the boat is given a GOOD saturation coat before applying the glass, the epoxy basically overrides the glue already there.
Steve ...

I would have to agree with you since we are on the same page with that thought. When a good saturation coat is applied it does just that ... saturates the wood. In my humble way of thinking the epoxy replaces or modifies the glue that is there making it a lot stronger on the bond to the wood. Besides sealing and protecting the wood from dry rot and adding some strength to it.

Heck if some dry rot shows ( something I have not had happen to any of my boats) up a good epoxy saturation cures it and make everything solid again. I know this for a fact since some wood here at the house got some dry rot in it and I mixed up some of the Smiths penetrating epoxy and the soft wood is brick hard. Some folks on the forum have done the same with soft spots using the same epoxy we make the boats with.

Even Smiths advise using the epoxy for repairing soft spots in large boats without having to replace the wood, guess that is why they sell it. :lol: I haven't tried saturating a panel with it but I would bet it would saturate all the way through the panel. Some folks think that the epoxy we use doesn't go all the way to the inside , even when doing both side of the panel , I think it does.

Chuck.
 

Steve

Well-Known Member
I can give you that one, Jack. . .as I am not an expert. . .but it is my opinion. . . I look at my "epoxy overrides the glue" and realize that I coulda used better words 'cause "override" is the wrong word. . . I do know when I give my plys a GOOD and THOROUGH saturation, I've been able to submerge it and when I take it out the water beads up and rolls off with no hard to the layers . . . but expoxy like so many things will not last forever so give it proper loving care and yer granchillun's granchillun can use dat boat
 

Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
168
84
Okemos / East Lansing Michigan
Epoxy overlays the wood and glue sandwich wherever it's applied. It soaks into the wood and adds strength to whatever strength is already there. Since a boat made of just plywood without any glass or epoxy can be quite strong, the added strength is a definite positive. Epoxy will not replace the internal original glue used to bond the plys together. And, as long as the epoxy encapsulation holds its integrity, the internal wood will remain dry.

Since, however, our boats are made to travel in a wet environment, and Nature being what it is, and Murphy's Law being still in effect - most builders prefer to protect their boat - and themselves - as much as they can. IE: waterproof glue to start out with. Both the plywood industry, and the boat building industry recommend that. Can we get away with violating that recommendation? Yep. Should we? That's an individual decision. Like all of our decisions, it is based on personal values.
 

gbinga

Well-Known Member
Nov 7, 2008
736
2
Hoschton, GA
One of us has got to do an experiment with the saturation coats on plywood.

I remain skeptical about whether anything is going to saturate past the glue line under the face ply. I just suspect that the glue line is going to stop anything from soaking past it. Can't prove it though, because I haven't run a test.

-IF- I am right, the epoxy isn't going very deep on luan because that surface ply is paper thin. Of course if you encapsulate inside and out, that should still be OK, but remember Murphy's law.

In any case lot's of people build boats out of cheap ply and epoxy, and use them hard, and have great results. Heck, I haven't ever spent more than $20 per sheet, so I'm not arguing. I just think it makes sense to stick with exterior product. It isn't like it costs that much more.

If I spent $40 on plywood for a pirogue and another guy spent $20, does that really add up to anything? Look at what the 'glass and resin costs!! Not to mention the value of your time and labor.

George