md

"mttt"

15/04/2004 5:37 PM

Bowed Veneer Panels?

Been 'sperimenting with resawing and veneering. Resawed some 6" wide, 30"
long 4/4 Jatoba stock into 1/8" slices. Was flat after the cut. Believe the
stock to be dry - but lack a moisture meter.

Edge glued (Titebond) the veneers together to get a 12" wide, 30" long
sheet. Then a couple of days later, glued (Titebond Extend) the 1/8" thick
veneers to 1/8" thick baltic birch - aiming to end up with a 1/4" thick door
in the end.

Both panels bowed up - one much more than the other. Bow is cross grain -
across the 12" width for the Jatoba.


When I was experimenting with some 4/4 Maple a week earlier - same sizes,
same thicknesses - the bowing also occurred but with the grain - along the
30" length.

I don't recall whether how I oriented the Baltic Birch panels underneath -
but was thinking since they're more plywood-ish than not, they should be
relativley stable.

Can anyone help me understand (a) what I could have done to prevent the
bowing [e.g was the stock too wet; too thin; wrong glue] and (b) what might
explain why the Jatoba bowed cross grain and the Maple bowed with grain???

[ Head scratchin'... ]
Thank you!


This topic has 6 replies

dD

[email protected] (DarylRos)

in reply to "mttt" on 15/04/2004 5:37 PM

15/04/2004 7:11 PM

>Can anyone help me understand (a) what I could have done to prevent the
>bowing [e.g was the stock too wet; too thin; wrong glue] and (b) what might
>explain why the Jatoba bowed cross grain and the Maple bowed with grain???

Did you glue a backing sheet to the panel? If you didn't it will certainly bow
up.

Also, Titebond is not the glue to use for veneers. Eventually it will creep on
you. Unibond 800 is better for veneering.

I don't know why they bowed differently. Possibly the way moisture got in the
panels, or how the glue dired, don't know. But if you glued a 1/8" veneer
sheet, which is fairly thinck for vener onto a 1/8" panel, you will always get
bowing. That's why you need to glue the back as well.

md

"mttt"

in reply to "mttt" on 15/04/2004 5:37 PM

16/04/2004 3:36 PM


"Gary" <[email protected]> wrote in message
news:[email protected]...
>
>
> To reiterate what Daryl said:
> If you veneer a panel - do the same thing to BOTH sides of the panel.
> Otherwise you'll have unequal stress on each face of the panel and some
sort
> of bowing, curling, twisting is inevitable.

Thanks! All part of the learning experience.

> On a side note: Jatoba is pretty cheap around here (less than 4 bucks a
> foot).

S3S 4/4 was $7.50 a BF @ Paxton here in Denver. [ When I saw their Cherry
for $9.50 a BF (OK it was 4/4 *wide* stock, but still!) I started to wonder
if their prices are going a smidge out'a line. Might be time to try a Steve
Wall UPS bundle. ]


> Unless it's a highly figured piece of wood and all you're looking for
> is a 1/4" piece - why not just use solid wood?

Just looking to get in some practice. Am new at this and wanted to practice
resawing.

> Veneering and resawing is
> best saved for rarer woods and figured woods you want to get more out of
or
> do things like bookmatches with.

Am glad I'm practicing on more common and cheaper stock - cuz I seem to be
screwing it up! :)
Thanks again for the lesson.

KW

Kim Whitmyre

in reply to "mttt" on 15/04/2004 5:37 PM

15/04/2004 12:25 PM

In article <[email protected]>, do-not-
[email protected] says...
> Can anyone help me understand (a) what I could have done to prevent the
> bowing [e.g was the stock too wet; too thin; wrong glue] and (b) what might
> explain why the Jatoba bowed cross grain and the Maple bowed with grain???
>
>
From my reading, "Making Traditional English Furniture," the author uses
only hide glue, and he applies glue to both sides. He fixes it to the
substrate with the glue, hammers it out from the center, and then
applies glue to the top surface. He then uses a hot, moist towel (as hot
as you can manage to hold) to wipe down the surface, thereby removing
excess glue. Of course, you can't do that with titebond. . .

Kim

Gg

"Gary"

in reply to "mttt" on 15/04/2004 5:37 PM

16/04/2004 12:27 PM

To reiterate what Daryl said:
If you veneer a panel - do the same thing to BOTH sides of the panel.
Otherwise you'll have unequal stress on each face of the panel and some sort
of bowing, curling, twisting is inevitable.
When I veneer I always have some "cheaper" quality veneer handy to do the
back sides of panels. Just as long as it's the same relative thickness and I
glue it the same way (same glue type) and with same grain orientation.
One thing you'll note on plywood - it's almost always made up of an ODD
number of sheets of veneers - that's to balance out the stress in the panel.
On a side note: Jatoba is pretty cheap around here (less than 4 bucks a
foot). Unless it's a highly figured piece of wood and all you're looking for
is a 1/4" piece - why not just use solid wood? Veneering and resawing is
best saved for rarer woods and figured woods you want to get more out of or
do things like bookmatches with.

Gary


"mttt" <[email protected]> wrote in message
news:[email protected]...
> Been 'sperimenting with resawing and veneering. Resawed some 6" wide, 30"
> long 4/4 Jatoba stock into 1/8" slices. Was flat after the cut. Believe
the
> stock to be dry - but lack a moisture meter.
>
> Edge glued (Titebond) the veneers together to get a 12" wide, 30" long
> sheet. Then a couple of days later, glued (Titebond Extend) the 1/8" thick
> veneers to 1/8" thick baltic birch - aiming to end up with a 1/4" thick
door
> in the end.
>
> Both panels bowed up - one much more than the other. Bow is cross grain -
> across the 12" width for the Jatoba.
>
>
> When I was experimenting with some 4/4 Maple a week earlier - same sizes,
> same thicknesses - the bowing also occurred but with the grain - along the
> 30" length.
>
> I don't recall whether how I oriented the Baltic Birch panels underneath -
> but was thinking since they're more plywood-ish than not, they should be
> relativley stable.
>
> Can anyone help me understand (a) what I could have done to prevent the
> bowing [e.g was the stock too wet; too thin; wrong glue] and (b) what
might
> explain why the Jatoba bowed cross grain and the Maple bowed with grain???
>
> [ Head scratchin'... ]
> Thank you!
>
>

Gg

"Gary"

in reply to "mttt" on 15/04/2004 5:37 PM

16/04/2004 3:49 PM

MTTT,
I just bought a bunch of Jatoba at the Paxtons here in KC. Think it was
$3.90 a board foot. That's why I commented on using solid wood. Think cherry
is around 6 to 6.50 these days (which is why I switched to the Jatoba on my
last project). Can't believe they have they much of a price differential
between stores even if it is in a different region. Bet you could pick some
up cheaper via mail order from somewhere.

Next on my wish list is a decent bandsaw so I can practice on some resawing
as well. How did the Jatoba resaw? I enjoyed working with it on a table I
built, but the stuff is harder/denser than hell.

Good luck with the practicing!

Gary

"mttt" <[email protected]> wrote in message
news:[email protected]...
>
> "Gary" <[email protected]> wrote in message
> news:[email protected]...
> >
> >
> > To reiterate what Daryl said:
> > If you veneer a panel - do the same thing to BOTH sides of the panel.
> > Otherwise you'll have unequal stress on each face of the panel and some
> sort
> > of bowing, curling, twisting is inevitable.
>
> Thanks! All part of the learning experience.
>
> > On a side note: Jatoba is pretty cheap around here (less than 4 bucks a
> > foot).
>
> S3S 4/4 was $7.50 a BF @ Paxton here in Denver. [ When I saw their Cherry
> for $9.50 a BF (OK it was 4/4 *wide* stock, but still!) I started to
wonder
> if their prices are going a smidge out'a line. Might be time to try a
Steve
> Wall UPS bundle. ]
>
>
> > Unless it's a highly figured piece of wood and all you're looking for
> > is a 1/4" piece - why not just use solid wood?
>
> Just looking to get in some practice. Am new at this and wanted to
practice
> resawing.
>
> > Veneering and resawing is
> > best saved for rarer woods and figured woods you want to get more out of
> or
> > do things like bookmatches with.
>
> Am glad I'm practicing on more common and cheaper stock - cuz I seem to be
> screwing it up! :)
> Thanks again for the lesson.
>
>

md

"mttt"

in reply to "mttt" on 15/04/2004 5:37 PM

16/04/2004 7:36 PM


"Gary" <[email protected]> wrote in message
news:[email protected]...
>
>
> MTTT,
> last project). Can't believe they have they much of a price differential
> between stores even if it is in a different region. Bet you could pick
some

Me neither. On my to-do list to hit some of the other dealers in town and
compare prices.

>
> Next on my wish list is a decent bandsaw so I can practice on some
resawing
> as well. How did the Jatoba resaw? I enjoyed working with it on a table I
> built, but the stuff is harder/denser than hell.

Surprisinginly easier than I expected. Given it's Janka rating, I was
expecting a real battle. Perhaps if I had a riser block and was trying to
resaw 12" wide stock. But it went through with only moderate more (granted
subjective) pressure than the maple.

Blade was a Suffolk saw (AS 1/2 inch 3tpi, IIRC) . Had a WoodSlicer but
decided to try the Suffolk blade first since I had it tracked and tensioned.

On the table saw, it was only 4/4 stock, but that DeWalt 40 tooth Series 60
blade I picked up for $29 did a wonderful job. The only burns were my
fault, pausing to grasp for the push stick.

>
> Good luck with the practicing!

Thanks - I'm going to need it! ;->



>
> Gary
>
> "mttt" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "Gary" <[email protected]> wrote in message
> > news:[email protected]...
> > >
> > >
> > > To reiterate what Daryl said:
> > > If you veneer a panel - do the same thing to BOTH sides of the panel.
> > > Otherwise you'll have unequal stress on each face of the panel and
some
> > sort
> > > of bowing, curling, twisting is inevitable.
> >
> > Thanks! All part of the learning experience.
> >
> > > On a side note: Jatoba is pretty cheap around here (less than 4 bucks
a
> > > foot).
> >
> > S3S 4/4 was $7.50 a BF @ Paxton here in Denver. [ When I saw their
Cherry
> > for $9.50 a BF (OK it was 4/4 *wide* stock, but still!) I started to
> wonder
> > if their prices are going a smidge out'a line. Might be time to try a
> Steve
> > Wall UPS bundle. ]
> >
> >
> > > Unless it's a highly figured piece of wood and all you're looking for
> > > is a 1/4" piece - why not just use solid wood?
> >
> > Just looking to get in some practice. Am new at this and wanted to
> practice
> > resawing.
> >
> > > Veneering and resawing is
> > > best saved for rarer woods and figured woods you want to get more out
of
> > or
> > > do things like bookmatches with.
> >
> > Am glad I'm practicing on more common and cheaper stock - cuz I seem to
be
> > screwing it up! :)
> > Thanks again for the lesson.
> >
> >
>
>


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