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264784 "Joseph Sullivan" <joe@j...> 2018‑01‑22 Crotch wood construction
John:

That crotch panel cabinet is lovely, as your work always is.  

As you have obviously worked with walnut crotch, maybe you can guide me.  I
have about 8 sizeable book-matched panels (four pair), plus some more
un-re-sawn slabs of crotch in the wood shed.  The panels range from 2 to 3
feet long, and from 1/8 to 3/8 in thickness.  You may recall that a week or
so ago I was asking about how crotch grain, wild as it is, expands and
contracts.  I am still pondering that.

Meanwhile, though, I have these panels and slabs.  Seems to me that 1/8
crotch is not inherently all that strong.  Do you think that at 1/8 I can
treat it as veneer and hard-glue it to a substrate?  I am under the
impression that some old sawn veneer (as opposed to sliced) was about that
thick if not more so.  How about the 3/8?  If so, how would you or any
galoot reading this orient the grain of the substrate?

Of course, with 3/8, I could certainly do as you have done and mount the
panels in frames.  It is just that A) I worry about the strength of the 1/8
if struck or shoved (grandchildren don't you know); and B) I have a concept
for a clock door panel in which the book matched panels are butted at the
bottom -- the wide part of the pattern -- and tapered each way up and down
vertically.  That would not be as effective a design if there were a frame
bar in between.

I have two half-ellipses of crotch wood with heavy figure that I intend to
make into t coffee table top by butting the two, joining underneath with
butterfly keys, and then cutting an actual elliptical shape.  In that case,
the mechanical joints would be the butterfly keys, and the understructure
would give solid support.  However, those slabs are now planed to
full-dimensional 4/4.  They have the heft to take the butterfly keys and to
support their own weight.  Obviously a different approach is required for
1/8 or even 3/8 stock.

Any thoughts?

Joe

Joseph Sullivan
264786 William Ghio <bghio@m...> 2018‑01‑23 Re: Crotch wood construction
> On Jan 22, 2018, at 5:38 PM, Joseph Sullivan  wrote:
> 
> Meanwhile, though, I have these panels and slabs.  Seems to me that 1/8
> crotch is not inherently all that strong.  Do you think that at 1/8 I can
> treat it as veneer and hard-glue it to a substrate?  I am under the
> impression that some old sawn veneer (as opposed to sliced) was about that
> thick if not more so.  How about the 3/8?  If so, how would you or any
> galoot reading this orient the grain of the substrate?
> 
> Any thoughts?

I have worked with some Sycamore burl. It was cut on a bandsaw mill and then run
thru a wide belt sander till it was flat and 5/16” thick.

Here are the tables I made:
https://www.flickr.com/photos/77280442@N.../17151098276/in/album-721576
51948412996/">https://www.flickr.com/photos/77280442@N.../17151098276/in/album-7
2157651948412996/
Album here: https://www.flickr.com/photos/77280442@N.../albums/72157651
948412996/with/17176432911/">https://www.flickr.com/photos/77280442@N.../albums/
72157651948412996/with/17176432911/

Later I made a box using some leftover material:
https://www.flickr.com/photos/77280442@N.../albums/72157656333193606

This is burl and the grain runs every which way. About 50% of what you see in
the pics is end grain. Very brittle stuff. For the tables I glued it to 3/8”
plywood, then planed it down to about 3/16” thickness of burl, i.e., a thick
veneer. Almost three years and the tops have held up well.

The box was done a short time later. I glued the burl to the ply, then re-sawed
them so they were balanced at about 3/16 of each. I planed the veneer off the
edges to make the ply a tongue and inserted that into a groove ploughed into the
sides of the box. I know you are supposed to veneer both sides but what is ply
if not a veneer already? It has worked fine.

Hope some ideas here may help.

Bill
264788 "Joseph Sullivan" <joe@j...> 2018‑01‑23 Re: Crotch wood construction
SNIP:

I have worked with some Sycamore burl. It was cut on a bandsaw mill and then run
thru a wide belt sander till it was flat and 5/16” thick.


SNIP
This is burl and the grain runs every which way. About 50% of what you see in
the pics is end grain. Very brittle stuff. For the tables I glued it to 3/8”
plywood, then planed it down to about 3/16” thickness of burl, i.e., a thick
veneer. Almost three years and the tops have held up well.

END SMIP

Very interesting.  Beautiful stuff, too.  I was considering using ply as well.
At 3/16ths, it is very close to my +- 1/8 stock.  What glue did you use?  I have
heard people who swear that veneers need special glue, but as I have never
worked with it, I am in the dark.  My inclination would have been to use
Tightbond II but the last thing I want to do is mess up a painstakingly built
piece by using the wrong glue.

Joe
264789 Don Schwartz <dks@t...> 2018‑01‑23 Re: Crotch wood construction
On 2018-01-22 8:48 PM, Joseph Sullivan wrote:
> Very interesting.  Beautiful stuff, too.  I was considering using ply as well.
At 3/16ths, it is very close to my +- 1/8 stock.  What glue did you use?  I have
heard people who swear that veneers need special glue, but as I have never
worked with it, I am in the dark.  My inclination would have been to use
Tightbond II but the last thing I want to do is mess up a painstakingly built
piece by using the wrong glue.
>
> Joe

The traditional adhesive is a form of hide glue. with low Bloom 
strength. See Lee Valley for a bit of info. It is used where great 
strength isn't needed. Because it it is relatively slow to gel, it gives 
you time to position the veneer. The great advantage of hide glue is 
that it can readily be softened with heat should things go south, and 
you need to lift the veneer for a second try. And you don't need to 
scrape it off should that happen! It will stick to itself. I wold not 
use Titebond.

FWIW

Don

-- 
"You can tell a man that boozes by the company he chooses"
The Famous Pig Song, Clarke Van Ness

The harder they come, the bigger they fall." Ry Cooder

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