Joining plywood

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upspirate

Joining plywood

Post by upspirate » Sun Mar 16, 2008 12:52 pm

Interesting way to join plywood panels:

http://www.duckworksmagazine.com/06/how ... /index.htm

Anyone done this?I don't like the final pattern if you are finishing bright,but for paint it would be ok

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tsmitherman
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Post by tsmitherman » Mon Mar 24, 2008 11:15 am

I saw a similar method used for plywood canoe construction several years ago. The builder told me that he cut a finger joint pattern from 1/2" MDF, and used a router with a pattern bit to cut the plywood.

If I remember correctly, his fingers were about 3" long and spaced about 1" wide, with rounded tips. After cutting the joints, he epoxied the panels together. The canoe was then finished with FG.

The joints on his canoe really looked pretty good under a clear finish.

I am considering using this method for my Bo-Jest project.
Tom
------------------------------
36' 1969 Willard Aft-Pilothouse Trawler
Blog: www.genesisboat.blogspot.com


Knot-So-Fast (BoJest) SOLD

"It's amazing what one can do when one doesn't know what one can't do." - Garfield

basilkies
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Re: Joining plywood

Post by basilkies » Mon Mar 24, 2008 2:34 pm

upspirate wrote:Interesting way to join plywood panels:

http://www.duckworksmagazine.com/06/how ... /index.htm

Anyone done this?I don't like the final pattern if you are finishing bright,but for paint it would be ok
The question that comes to mind is: What is the shear strength of epoxy as opposed to the pulling away strength? The puzzle joint would break under a shearing type load and the scarf joint has both pulling and shear forces.

It also seems like the puzzle joint would also be spreading the load over a narrower area, so I would guess it would cause a funny flex in that spot. But, hey, who knows, all you can do is test it or find out from someone who has.

ED3
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Interesting

Post by ED3 » Wed Mar 26, 2008 5:38 pm

But I would not use that type of joint for anything structural. Besides, it is easier to do a regular scarf with epoxy. Just takes a little practice.

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BruceDow
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Post by BruceDow » Sun Apr 27, 2008 4:46 pm

Here is a variation on the "puzzle joint" that is a little more condusive to a bright finish.

(It took me a while to chime in on this, because I needed to get up to the lake to take the picture)

This is the fore-deck of a kayak I built from a kit. The pieces came pre-cut. With some patience, one could create something similar by hand or by using a router template.

The back of the joint is reinfoced with fiberglass cloth and epoxy.


Image
Bruce.

~~ Do what you love, and love what you do. ~~
~~ To me - only my boat is not yet perfect. Everybody else's is to be admired for I know the path they have walked (Dave Lott, 2010) ~~
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Jones
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Re: Interesting

Post by Jones » Sun Apr 27, 2008 7:58 pm

ED3 wrote:But I would not use that type of joint for anything structural. Besides, it is easier to do a regular scarf with epoxy. Just takes a little practice.
Wise words.
Avoid Haste.

John K
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Post by John K » Thu May 01, 2008 5:28 am

My first build in the 70's I was able to buy 16 ft marine plywood. No joints on that boat. Cannot find that anymore.

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Cec
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Post by Cec » Thu May 08, 2008 1:51 pm

John K wrote:My first build in the 70's I was able to buy 16 ft marine plywood. No joints on that boat. Cannot find that anymore.
I'm not sure I could afford it if I could find it
Some mornings it just doesn't seem worth it to gnaw through the leather straps.

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