Dd

Dan

14/09/2007 2:10 PM

Edge joining thin plywood?

Folks --

This question came up while looking at some old project plans. They
were done up using cardboard mockups to get ideas of proportion and
space.

Lots of these used the "sliding card" principle of assembly Notches in
components would all slide and click together and you would get a
useful object from a set of flat parts. The sliding method can wait
for some other day......

What I found was that one idea for a basket/Tub involved joining thin
( 1/4 inch plywood ) I had thought that perhaps it would be better
to fetch in some sheet metal and just pop rivet the edges together.
However, a trip today thru the book store ( we have the school for
american craftsman on the RIT campus ) I noticed one of the displays
had been done using a nice grade of plywood butt jointed together and
fastened with staples.

Any know of a good way to join thin plywood pieces?

--dan


This topic has 7 replies

Rd

Robatoy

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 3:43 PM

On Sep 14, 5:10 pm, Dan <[email protected]> wrote:
> Folks --
>
> This question came up while looking at some old project plans. They
> were done up using cardboard mockups to get ideas of proportion and
> space.
>
> Lots of these used the "sliding card" principle of assembly Notches in
> components would all slide and click together and you would get a
> useful object from a set of flat parts. The sliding method can wait
> for some other day......
>
> What I found was that one idea for a basket/Tub involved joining thin
> ( 1/4 inch plywood ) I had thought that perhaps it would be better
> to fetch in some sheet metal and just pop rivet the edges together.
> However, a trip today thru the book store ( we have the school for
> american craftsman on the RIT campus ) I noticed one of the displays
> had been done using a nice grade of plywood butt jointed together and
> fastened with staples.
>
> Any know of a good way to join thin plywood pieces?
>

Luthiers butt-join pieces much thinner than that. As Chris pointed
out, you'd want a good fit.
A single pass with a 1/4" router bit (straight) along a fence, which
cuts through both pieces at the same time (sometimes called a
'dutchman') will give you a perfect fit.

The joint will be stronger than the wood, if done properly.

FH

Father Haskell

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 8:00 PM

On Sep 14, 6:43 pm, Robatoy <[email protected]> wrote:
> On Sep 14, 5:10 pm, Dan <[email protected]> wrote:
>
>
>
> > Folks --
>
> > This question came up while looking at some old project plans. They
> > were done up using cardboard mockups to get ideas of proportion and
> > space.
>
> > Lots of these used the "sliding card" principle of assembly Notches in
> > components would all slide and click together and you would get a
> > useful object from a set of flat parts. The sliding method can wait
> > for some other day......
>
> > What I found was that one idea for a basket/Tub involved joining thin
> > ( 1/4 inch plywood ) I had thought that perhaps it would be better
> > to fetch in some sheet metal and just pop rivet the edges together.
> > However, a trip today thru the book store ( we have the school for
> > american craftsman on the RIT campus ) I noticed one of the displays
> > had been done using a nice grade of plywood butt jointed together and
> > fastened with staples.
>
> > Any know of a good way to join thin plywood pieces?
>
> Luthiers butt-join pieces much thinner than that. As Chris pointed
> out, you'd want a good fit.
> A single pass with a 1/4" router bit (straight) along a fence, which
> cuts through both pieces at the same time (sometimes called a
> 'dutchman') will give you a perfect fit.
>
> The joint will be stronger than the wood, if done properly.

Traditionally done with a shooting board and plane. Fit is
close enough that the pieces don't even need to be clamped,
just rubbed and pressed together until the horse glue cools.

Joints in guitar bodies are usually reinforced by cleats or braces.

FH

Father Haskell

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 8:15 PM

On Sep 14, 5:10 pm, Dan <[email protected]> wrote:
> Folks --
>
> This question came up while looking at some old project plans. They
> were done up using cardboard mockups to get ideas of proportion and
> space.
>
> Lots of these used the "sliding card" principle of assembly Notches in
> components would all slide and click together and you would get a
> useful object from a set of flat parts. The sliding method can wait
> for some other day......
>
> What I found was that one idea for a basket/Tub involved joining thin
> ( 1/4 inch plywood ) I had thought that perhaps it would be better
> to fetch in some sheet metal and just pop rivet the edges together.
> However, a trip today thru the book store ( we have the school for
> american craftsman on the RIT campus ) I noticed one of the displays
> had been done using a nice grade of plywood butt jointed together and
> fastened with staples.
>
> Any know of a good way to join thin plywood pieces?

Cut the joints straight and use yellow glue. The joints will
flex before they snap. Clamp the panels together with a "mold,"
that is, a sheet of 3/4" ply with tacks around the panels
less an eighth of an inch so that pressing down on the joint will
force the panels together -- if your finished glueup is 12" wide,
you'll have two rows of tacks on your mold board set 11-7/8"
apart. Masking tape under the joint will keep the panels from
gluing themselves to the mold.

SC

"Scott Cox"

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 4:38 PM

"Scarf" join them with opposing rabbets.



"Dan" <[email protected]> wrote in message
news:[email protected]...
> Folks --
>
> This question came up while looking at some old project plans. They
> were done up using cardboard mockups to get ideas of proportion and
> space.
>
> Lots of these used the "sliding card" principle of assembly Notches in
> components would all slide and click together and you would get a
> useful object from a set of flat parts. The sliding method can wait
> for some other day......
>
> What I found was that one idea for a basket/Tub involved joining thin
> ( 1/4 inch plywood ) I had thought that perhaps it would be better
> to fetch in some sheet metal and just pop rivet the edges together.
> However, a trip today thru the book store ( we have the school for
> american craftsman on the RIT campus ) I noticed one of the displays
> had been done using a nice grade of plywood butt jointed together and
> fastened with staples.
>
> Any know of a good way to join thin plywood pieces?
>
> --dan
>

CF

Chris Friesen

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 3:41 PM

Dan wrote:

> Any know of a good way to join thin plywood pieces?

How about glue? 1/4" is a reasonable width, but you'd want to have
fairly accurate cuts.

Chris

DG

"Dave Gordon"

in reply to Dan on 14/09/2007 2:10 PM

15/09/2007 3:53 PM


"Scott Cox" <[email protected]> wrote in message news:[email protected]...
> "Scarf" join them with opposing rabbets.
>

Thats a stepped scarf. Better would be a tapered scarf

http://en.wikipedia.org/wiki/Scarf_joint

Modern glues make this a pretty strong joint.

>
> "Dan" <[email protected]> wrote in message
> news:[email protected]...
>> Folks --
>>
>> This question came up while looking at some old project plans. They
>> were done up using cardboard mockups to get ideas of proportion and
>> space.
>>
>> Lots of these used the "sliding card" principle of assembly Notches in
>> components would all slide and click together and you would get a
>> useful object from a set of flat parts. The sliding method can wait
>> for some other day......
>>
>> What I found was that one idea for a basket/Tub involved joining thin
>> ( 1/4 inch plywood ) I had thought that perhaps it would be better
>> to fetch in some sheet metal and just pop rivet the edges together.
>> However, a trip today thru the book store ( we have the school for
>> american craftsman on the RIT campus ) I noticed one of the displays
>> had been done using a nice grade of plywood butt jointed together and
>> fastened with staples.
>>
>> Any know of a good way to join thin plywood pieces?
>>
>> --dan
>>
>
>

Ll

Leuf

in reply to Dan on 14/09/2007 2:10 PM

14/09/2007 10:49 PM

On Fri, 14 Sep 2007 14:10:18 -0700, Dan <[email protected]> wrote:

>Folks --
>
>This question came up while looking at some old project plans. They
>were done up using cardboard mockups to get ideas of proportion and
>space.
>
>Lots of these used the "sliding card" principle of assembly Notches in
>components would all slide and click together and you would get a
>useful object from a set of flat parts. The sliding method can wait
>for some other day......
>
>What I found was that one idea for a basket/Tub involved joining thin
>( 1/4 inch plywood ) I had thought that perhaps it would be better
>to fetch in some sheet metal and just pop rivet the edges together.
>However, a trip today thru the book store ( we have the school for
>american craftsman on the RIT campus ) I noticed one of the displays
>had been done using a nice grade of plywood butt jointed together and
>fastened with staples.
>
>Any know of a good way to join thin plywood pieces?

What kind of 1/4" ply? If it's 3 ply with thin outer plies and a
thick center then you can make a decent glue joint so long as you have
the grain of the outer plies perpendicular to the joint. If you've
got 5 ply baltic birch with all the plies the same thickness then
you'll get a better glue joint with the outer plies parallel to the
joint.

Usually you have some kind of a back or bottom on the piece which
provides a lot of strength to keep those joints from racking.

For something like a basket/tub, well I would probably make it like a
drawer. Dovetail the corners and the bottom sits in a groove. But I
wouldn't be using ply for the sides.


-Leuf


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