I've done a bit of glue-ups. Most have been successful. Some have been
disastrous, but with each failure, I've been able to figure out what I
did wrong and not repeat it too many times. All have been with pine,
maple, or oak.
At this point, the glue-ups I find easiest to do are laminations or edge
gluing. If the surfaces are clean and planed smooth, and the clamping
pressure is enough, the joint will hold for me.
The other day I went to the kindling pile to get some wood for turning a
knob. I didn't have the size I needed, so I decided to take 2 pieces and
face-glue them together to give me the thickness I needed. I'm fairly
sure the pieces were walnut. The glue was Titebond III
The first two pieces fell apart by hand. I was in a hurry and used weak
clamps. I also didn't wait long enough for the glue to bond.
The second two pieces went better but fell apart when I was turning on
the lathe. Same for the third set. Both of the second sets had much
stronger clamps and I waited a full day.
In all cases, the faces were flat and smooth, planed by hand.
What am I doing wrong?
Tanus
Well, I'm mostly corn-fused about glue thickness and pressure. Fine
for a lab or industrial setting, but for me it seems reasonable to put
a smooth coating on both sides, them clamp "tightly." When I've tried
to break glue joints later, the wood separates indicating the glue was
strong enough.
In the OP, the one thing I noticed was the lack of time between gluing
and working. I think the Titebond label says something like "sets in
30 mins, full strength in 24 hours." I always wait 'bout an hour to
unclamp, then overnight before I trust the joint. And if I don't need
the clamps right away, they usually remain clamped overnight.
I think all of the above suggestions have merit, but the big factor
would seem to be the time between gluing and working.
Hope this helps.....
J. Clarke wrote:
> If one needs "very high pressures" to achieve 3-6 mil bond line
> thickness then one is applying too much glue. Note that the table of
> "recommended clamping pressures" in the Roman Rablej article in Fine
> Woodworking appears to have been pulled out of Rablej's ass. He gives
> no source for it at all.
It may not be the case that a 3-6 mil thickness is always ideal. If so,
then higher pressures may be better.
As "dpb" mentioned in this newsgroup when the FWW article came out, I'd
guess the pressures came from Rabiej's paper:
"The Effect of Clamping Pressure and Orthotropic Wood Structure on the
Strength of Glued Bonds", Wood and Fiber Science Vol. 24, No. 3, July 1992.
From the abstract at
"http://swst.metapress.com/content/1050536165217317/?p=8b5006db06be4640acd2801679e46c4e&pi=3"
"...Using this concept, the optimum clamping pressure for sugar maple
was found to be 0.3 times compression strength using U-F glue and 0.5
times using PVAc glue. This approach to determining reliable clamping
pressure data can lead to improved gluing practice and more precise
testing procedures."
Using the FPL tables, this gives a bit over 700psi for PVA glue.
Chris
On Tue, 27 May 2008 18:33:50 -0400, Tanus
<[email protected]> wrote:
>
>The glue hasn't frozen but it has been cold. I've used the glue recently
>and it's worked fine. Although I keep the glue in an unheated shop, the
>cabinet it's stored in is heated throughout the winter. Buying new glue
>is what I'll do next.
Howdy,
'Just curious...
How do you heat the cabinet?
Thanks,
--
Kenneth
If you email... Please remove the "SPAMLESS."
Did you do the "TV woodworker" type of glue up -- squirt a little glue on
one side and press together -- for the best bond, glue should be spread
evenly and lightly on both pieces and then clamped together. For working on
the final result, wait 24 hours, even though it looks glued, it may not be
set strong enough to withstand pressures and stresses.
"Tanus" <[email protected]> wrote in message news:[email protected]...
> I've done a bit of glue-ups. Most have been successful. Some have been
> disastrous, but with each failure, I've been able to figure out what I did
> wrong and not repeat it too many times. All have been with pine, maple, or
> oak.
>
> At this point, the glue-ups I find easiest to do are laminations or edge
> gluing. If the surfaces are clean and planed smooth, and the clamping
> pressure is enough, the joint will hold for me.
>
> The other day I went to the kindling pile to get some wood for turning a
> knob. I didn't have the size I needed, so I decided to take 2 pieces and
> face-glue them together to give me the thickness I needed. I'm fairly sure
> the pieces were walnut. The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on the
> lathe. Same for the third set. Both of the second sets had much stronger
> clamps and I waited a full day.
>
> In all cases, the faces were flat and smooth, planed by hand.
>
> What am I doing wrong?
>
> Tanus
On May 28, 4:39=A0pm, Kenneth <[email protected]> wrote:
> On Wed, 28 May 2008 15:37:56 -0700 (PDT), whit3rd
>
> <[email protected]> wrote:
> >(the pressure on a plane
> >blade can collapse the little cellulose tubes, and they
> >won't wick up the glue if they're not open).
> It seems to me that the comment would make sense only for
> end grain, so I suspect I am missing something.
The runup to D-day saw a massive effort to glue up plywood
into gliders, and the early batches didn't hold very well. The
trouble was traced to the platen presses (that held the
plies together to make loose bits into solid plywood).
(from _The New Science of Strong Materials_, J. E. Gordon)
"... a proportion of aircraft plywood was ungluable. The joints
in such plywood, made with all due care, looked like
any other joints but had no strength..."
The effect is sometimes called case-hardening, and is
due to microscopic damage that prevents the glue from
penetrating into the wood to make contact with
the subsurface (strong, intact) wood fibers.
Sandpaper is a good treatment for the problem.
On Mon, 26 May 2008 21:13:04 -0400, Tanus
<[email protected]> wrote:
>I've done a bit of glue-ups. Most have been successful. Some have been
>disastrous, but with each failure, I've been able to figure out what I
>did wrong and not repeat it too many times. All have been with pine,
>maple, or oak.
>
>At this point, the glue-ups I find easiest to do are laminations or edge
>gluing. If the surfaces are clean and planed smooth, and the clamping
>pressure is enough, the joint will hold for me.
>
>The other day I went to the kindling pile to get some wood for turning a
>knob. I didn't have the size I needed, so I decided to take 2 pieces and
>face-glue them together to give me the thickness I needed. I'm fairly
>sure the pieces were walnut. The glue was Titebond III
>
>The first two pieces fell apart by hand. I was in a hurry and used weak
>clamps. I also didn't wait long enough for the glue to bond.
>
>The second two pieces went better but fell apart when I was turning on
>the lathe. Same for the third set. Both of the second sets had much
>stronger clamps and I waited a full day.
>
>In all cases, the faces were flat and smooth, planed by hand.
>
>What am I doing wrong?
>
>Tanus
Howdy,
Is there any possibility that, at some point, the glue had
frozen?
All the best,
--
Kenneth
If you email... Please remove the "SPAMLESS."
"Tanus" wrote:
> I could have. That epoxy is stored inside and I'm sure it's fine.
> It's also expensive as hell, and I don't want to use it for ordinary
> glue-ups. I'm certainly a convert, Lew. The stuff is amazing in
> tough-to-fix jobs, but for this, if I had considered it, would have
> seemed a waste. I'm also sure that it would have worked well.
Prices vary widely for epoxy and amount purchased has a major impact
on pricing.
Not sure what "It's also expensive as hell" means price wise, but a 1
gallon kit is worth a look.
Lew
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
>
> Too much pressure will result in a glue-starved joint. I think many
> people go overboard on the clamping pressure with Titebond and the
> like.
No, it will not, that is an old wives tale. The only way you get glue
starvation is to not apply enough in the first place or scrape it all off
during insertion. A mortise and tennon joint that fits too tightly can
scrape all the glue off during assembly.
In article <bWR_j.5654$u7.3933@trnddc07>, [email protected]
says...
> > What am I doing wrong?
>
> Hard to say but it is obvious that either your glue is no good or the wood
> surfaces being glued were "dirty". I suspect the latter.
>
> Was the "kindling pile" inside or outside? Did you machine or sand the wood
> surfaces to be glued so that you had nice fresh, dry, unoxidized,
> unweathered wood for the glue?
>
My first thought at that sort of spectacular glue failure would
be 'wet wood'. Wet is not always obvious, but wood above a
certain moisture content does not seem to bond well with any
waterbased glues that I've used (I haven't used titebond, since
it's not commonly sold in these parts; but I understand it to
be a member of the 'white glue'/pva/aliphatic family, also).
-P.
--
=========================================
firstname dot lastname at gmail fullstop com
Tanus wrote:
> Leon wrote:
>
>>
>> Well, Walnut has nothing to do with it. The glue may not be fully
>> cured and with a joint spinning and pulling it could fail if not
>> properly cured.
>> Walnut is NOT incredibly strong, did the joint fail or did the wood
>> fail close to the joint?
>>
>
> Sorry guys.I should have given more information.
>
> All joints failed at the glue. In other words, the pieces pretty much
> fell apart with no wood breaking.
>
> The glue hasn't frozen but it has been cold. I've used the glue recently
> and it's worked fine. Although I keep the glue in an unheated shop, the
> cabinet it's stored in is heated throughout the winter. Buying new glue
> is what I'll do next.
>
> I liked the idea of staving the joint until more than a few of you said
> that likely wasn't the case, which is bringing me back to bad glue.
>
> The faces were hand planed and very smooth to the touch. No sanding
> after planing. I squeezed the glue in a zig zag along both surfaces and
> then smoothed with a finger so the glue was even on both.
>
> There is some doubt in my mind about the wood being walnut. I'll verify
> that later. However, the wood from the kindling pile was very dry. I get
> my kindling from a cabinet shop locally, and store it in a shed before
> and after sawing it to length.
>
> I'll get some more glue and try this thing again. In the interim, I made
> my knobs from other stock, but this idea of glue failing is not one I
> want to repeat.
>
> Thanks all of you for the replies. I didn't think this was going to
> generate so much. I'm glad I asked.
>
> Tanus
Some woods such as Hond. cherry have oil in them and the surface needs
to be wipe with Acetone just prior to gluing, otherwise it will just
seperate as I found out.
"Tanus" <[email protected]> wrote:
> What am I doing wrong?
Remember your experience with epoxy?
Patience is a virtue.
Neither epoxy or TiteBond like cold weather or being put to work
before they are ready.
Lew
J. Clarke wrote:
> For certain values of "scientifically". And hardly "old wives tale"
> when the glue manufacturers agree with years of serious research by
> the likes of Forest Products Laboratories that for each type of glue
> there is an optimal glue line thickness, the achievement of which
> depends on the type of wood, the grain orientation, the viscosity of
> the glue, and the clamping pressure.
Yep. And for hard maple and PVA the optimal glue line thickness
resulted from very high pressures...substantially more than the 250psi
that is at the upper end of Franklin's recommendations.
However, as "dpb" mentioned, optimal is not normally necessary, and
quite adequate joints can be made at much lower pressure.
> As for "the pressure generated by hand clamps", how much pressure is
> that? That depends on the joint geometry. Don't confuse "force" with
> "pressure".
Absolutely true. Common misconception.
Chris
Tanus wrote:
> The other day I went to the kindling pile to get some wood for turning a
> knob. I didn't have the size I needed, so I decided to take 2 pieces and
> face-glue them together to give me the thickness I needed. I'm fairly
> sure the pieces were walnut. The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on
> the lathe. Same for the third set. Both of the second sets had much
> stronger clamps and I waited a full day.
two things come to mind:
1 - bad glue - i'd consider this most likely - go to the borg and get a
new bottle of titebond and try again.
2 - oily wood? Don't know what your kindling pile is, so is it possible
your two pieces are not walnut, but a more tropical wood that has a high
oil content?
On Wed, 28 May 2008 15:37:56 -0700 (PDT), whit3rd
<[email protected]> wrote:
>(the pressure on a plane
>blade can collapse the little cellulose tubes, and they
>won't wick up the glue if they're not open).
Howdy,
Could you say a bit more about that...?
It seems to me that the comment would make sense only for
end grain, so I suspect I am missing something.
All the best,
--
Kenneth
If you email... Please remove the "SPAMLESS."
Tanus wrote:
> I've done a bit of glue-ups. Most have been successful. Some have been
> disastrous, but with each failure, I've been able to figure out what I
> did wrong and not repeat it too many times. All have been with pine,
> maple, or oak.
>
> At this point, the glue-ups I find easiest to do are laminations or
> edge gluing. If the surfaces are clean and planed smooth, and the
> clamping pressure is enough, the joint will hold for me.
>
> The other day I went to the kindling pile to get some wood for
> turning a knob. I didn't have the size I needed, so I decided to take
> 2 pieces and face-glue them together to give me the thickness I
> needed. I'm fairly sure the pieces were walnut. The glue was
> Titebond III
> The first two pieces fell apart by hand. I was in a hurry and used
> weak clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on
> the lathe. Same for the third set. Both of the second sets had much
> stronger clamps and I waited a full day.
>
> In all cases, the faces were flat and smooth, planed by hand.
>
> What am I doing wrong?
Hard to say but it is obvious that either your glue is no good or the wood
surfaces being glued were "dirty". I suspect the latter.
Was the "kindling pile" inside or outside? Did you machine or sand the wood
surfaces to be glued so that you had nice fresh, dry, unoxidized,
unweathered wood for the glue?
BTW, clamp pressure depends much on the hardness of the wood; butternut is
soft, doesn't need as much pressure as walnut which is harder and walnut
doesn't need as much as hickory which is very hard. Same thing for
planarity of surfaces...one can get a satisfactory glue job with two
relatively rough, non-matching butternut surfaces by increasing the clamp
pressure...can't do that with hickory - or at least I can't.
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
"Tanus" <[email protected]> wrote in message news:[email protected]...
> I've done a bit of glue-ups. Most have been successful. Some have been
> disastrous, but with each failure, I've been able to figure out what I did
> wrong and not repeat it too many times. All have been with pine, maple, or
> oak.
>
> At this point, the glue-ups I find easiest to do are laminations or edge
> gluing. If the surfaces are clean and planed smooth, and the clamping
> pressure is enough, the joint will hold for me.
>
> The other day I went to the kindling pile to get some wood for turning a
> knob. I didn't have the size I needed, so I decided to take 2 pieces and
> face-glue them together to give me the thickness I needed. I'm fairly sure
> the pieces were walnut. The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on the
> lathe. Same for the third set. Both of the second sets had much stronger
> clamps and I waited a full day.
>
> In all cases, the faces were flat and smooth, planed by hand.
>
> What am I doing wrong?
>
> Tanus
I think I see a problem here. Try this:
Go to the lumber yard and get a "pine" 1 x what ever( ask for a cull it is
cheaper and will work fine). Cut the board into 2 inch wide strips about 10
inches long. Get a NEW bottle of glue, I like Titebond ll but any white or
yellow glue will work, Try to stay away from Titebond lll for this. Now
take two strips and put glue on about 6 inches on the end of one of them and
put them together so that you have a unglued surface on each end and the
glue joint in the middle ( you should have a "handle" on each end of the
glued up wood). Clamp and set aside to dry. You should do this with
several samples, changing the amount of glue, clamping pressure etc with
each sample, one with a lot of glue so that is runs out of the joint, one
with very little glue, one with glue spread evenly on one surface, one with
glue spread on both surfaces etc etc.. You should vary your clamping
method, strong clamp, light clamp, tape for clamp etc. Allow to dry for a
least 4 hours the longer the better. When cured take one of the "handles"
and place in a vice and whack the other end with a hammer until the joint
breaks, Look at the broken joint and you will see which method is strongest
and best for you. All wood should act pretty much the same with what ever
gluing method and glue you used, some better some worse depending on the
glue and wood but similar. Now you have a gluing method to use. Next on
the faces of the boards you glued up, you hand planned them, are you sure
that you got them perfectly flat? I find it hard to get them perfectly flat
with a hand plane, it seems to work better with a planner or jointer when
doing face glue ups.
On Wed, 28 May 2008 05:30:29 -0400, Tanus <[email protected]> wrote:
>dpb wrote:
>> Tanus wrote:
>> ....
>>> ... I'll get some new glue and give it another whirl.
>>
>> Out of (more or less idle) curiosity, any idea how old what you used
>> actually is? IIRC, a year is the suggested shelf life for TB III, but
>> I've seen no change in gluing properties of that kept far longer.
>>
>> It does tend to thicken somewhat and get stringy, but as noted on the
>> container, a jarring of the container (not stirring, but vibrating) will
>> reconstitute its properties unless it is, indeed, too far gone. (It's a
>> very unusual-behaving material in that regard; I've never observed a
>> similar characteristic in any other material).
>>
>> Also iirc, the chalk temperature is 47 F, so if it is cool at night yet
>> still above freezing, even if the glue is warm enough being stored in
>> the heated cabinet, if the wood is colder than that, it will cool the
>> glue and the result could be the failure of the type you observe. Does
>> the glue surface appear to be dry and chalky after the failures? If so,
>> that would be a very suggestive indicator of low temperature. I had
>> forgotten to mention the wood temperature as well as glue before.
>>
>> --
>
>I bought my current Titebond in early 2008, Jan or Feb. All temps, glue,
>wood and environment,
>were above 60 when the glueing was done, but overnite temps may have
>dipped into the 40s. I bring glueups into the house in the winter, but
>don't in spring/summer. This piece was so small, it would have been easy
>to bring it inside to cure overnite, but it never entered my mind.
>
>You may have something here.
>
>I"m still going to get new glue.
Back in high school wood shop days we would glue poplar up for lathe
turnings. We would glue a sacrificial piece on the bottom of the stack
with a piece of newspaper between the good stuff and the sacrificial.
When we were done turning we would pop off the sacrificial piece. It
somehow survive turnings. I do not know how safe the practice was but
I do not recall any disasters. I would bet we let that glued up stuff
dry a few days in a 70 degree shop.
<[email protected]> wrote in message
news:6a60e575-b779-406c-aeae-b421b9615740@r66g2000hsg.googlegroups.com...
> >
>> Too much pressure will result in a glue-starved joint.
>
> I read some research that proved this to be an old wives tale. Joints
> can be glue starved, BUT not at the pressure generated by hand clamps.
> The study was scientifically done and reported in a woodworking mag.
Correct.
"Kenneth" <[email protected]> wrote in message
news:[email protected]...
> On Mon, 26 May 2008 21:13:04 -0400, Tanus
> <[email protected]> wrote:
>
>>I've done a bit of glue-ups. Most have been successful. Some have been
>>disastrous, but with each failure, I've been able to figure out what I
>>did wrong and not repeat it too many times. All have been with pine,
>>maple, or oak.
>>
>>At this point, the glue-ups I find easiest to do are laminations or edge
>>gluing. If the surfaces are clean and planed smooth, and the clamping
>>pressure is enough, the joint will hold for me.
>>
>>The other day I went to the kindling pile to get some wood for turning a
>>knob. I didn't have the size I needed, so I decided to take 2 pieces and
>>face-glue them together to give me the thickness I needed. I'm fairly
>>sure the pieces were walnut. The glue was Titebond III
>>
>>The first two pieces fell apart by hand. I was in a hurry and used weak
>>clamps. I also didn't wait long enough for the glue to bond.
>>
>>The second two pieces went better but fell apart when I was turning on
>>the lathe. Same for the third set. Both of the second sets had much
>>stronger clamps and I waited a full day.
>>
>>In all cases, the faces were flat and smooth, planed by hand.
>>
>>What am I doing wrong?
>>
>>Tanus
>
> Howdy,
>
> Is there any possibility that, at some point, the glue had
> frozen?
>
> All the best,
> --
> Kenneth
>
> If you email... Please remove the "SPAMLESS."
Maybe the glue was old???
On Mon, 26 May 2008 21:13:04 -0400, Tanus <[email protected]> wrote:
>I've done a bit of glue-ups. Most have been successful. Some have been
>disastrous, but with each failure, I've been able to figure out what I
>did wrong and not repeat it too many times. All have been with pine,
>maple, or oak.
>
>At this point, the glue-ups I find easiest to do are laminations or edge
>gluing. If the surfaces are clean and planed smooth, and the clamping
>pressure is enough, the joint will hold for me.
>
>The other day I went to the kindling pile to get some wood for turning a
>knob. I didn't have the size I needed, so I decided to take 2 pieces and
>face-glue them together to give me the thickness I needed. I'm fairly
>sure the pieces were walnut. The glue was Titebond III
>
>The first two pieces fell apart by hand. I was in a hurry and used weak
>clamps. I also didn't wait long enough for the glue to bond.
>
>The second two pieces went better but fell apart when I was turning on
>the lathe. Same for the third set. Both of the second sets had much
>stronger clamps and I waited a full day.
>
>In all cases, the faces were flat and smooth, planed by hand.
>
>What am I doing wrong?
>
>Tanus
Allow the glue to cure 2 days before working the piece, longer if the
piece is large. Make sure the mating surfaces fit well before you
apply glue.
On Wed, 28 May 2008 18:19:12 -0700 (PDT), whit3rd
<[email protected]> wrote:
>On May 28, 4:39 pm, Kenneth <[email protected]> wrote:
>> On Wed, 28 May 2008 15:37:56 -0700 (PDT), whit3rd
>>
>> <[email protected]> wrote:
>> >(the pressure on a plane
>> >blade can collapse the little cellulose tubes, and they
>> >won't wick up the glue if they're not open).
>
>> It seems to me that the comment would make sense only for
>> end grain, so I suspect I am missing something.
>
>The runup to D-day saw a massive effort to glue up plywood
>into gliders, and the early batches didn't hold very well. The
>trouble was traced to the platen presses (that held the
>plies together to make loose bits into solid plywood).
>
>(from _The New Science of Strong Materials_, J. E. Gordon)
>"... a proportion of aircraft plywood was ungluable. The joints
>in such plywood, made with all due care, looked like
>any other joints but had no strength..."
>
>The effect is sometimes called case-hardening, and is
>due to microscopic damage that prevents the glue from
>penetrating into the wood to make contact with
>the subsurface (strong, intact) wood fibers.
>
>Sandpaper is a good treatment for the problem.
Howdy,
Thanks for that interesting comment...
All the best,
--
Kenneth
If you email... Please remove the "SPAMLESS."
On May 26, 6:13=A0pm, Tanus <[email protected]> wrote:
>...I'm fairly
> sure the pieces were walnut. =A0The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on
> the lathe. Same for the third set.
> In all cases, the faces were flat and smooth, planed by hand.
Two good possibilities: the wood may be too wet, or
resinous, and the glue isn't 'taking'. Or, your plane
could need sharpening (the pressure on a plane
blade can collapse the little cellulose tubes, and they
won't wick up the glue if they're not open).
Scuff-sanding after flattening the wood will deal with possibility
number two. Epoxy or polyurethane or hide glue
might work better on resinous woods.
Lamination is in some senses an easier gluing task than
making glue-up chunks, because of the large glue area.
Tanus wrote:
...
> The other day I went to the kindling pile to get some wood for turning a
> knob. I didn't have the size I needed, so I decided to take 2 pieces and
> face-glue them together to give me the thickness I needed. I'm fairly
> sure the pieces were walnut. The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
Well, that's obvious enough...
> The second two pieces went better but fell apart when I was turning on
> the lathe. Same for the third set. Both of the second sets had much
> stronger clamps and I waited a full day.
>
> In all cases, the faces were flat and smooth, planed by hand.
>
> What am I doing wrong?
I don't really have a clue -- a glue joint of that type should be
possible to make hold stronger than the wood itself simply w/ a "rub
fit" even w/o clamping at all.
I have only a few guesses (and they're all simply that w/ no more data
or observation)...
1. The source of the material from the woodpile makes me wonder--was
this dry lumber or scrap firewood that could possibly be wet? Seems
unlikely, but we're searching here...
2. The glue is old or your simply not using sufficient amount to get
good glue surface. Since same symptom w/ "weak" or "stronger" clamps,
I'm assuming you're not clamping to the point of glue starvation, but
that's another possibility.
3. Surfaces aren't very flat or are excessively burnished so no
porosity for glue. Would be very difficult w/ walnut given it's
open-pored characteristics but again...
I can think of very few glue joints that didn't hold ever over 30 years
and virtually all of them could be attributed to either trying to make
ill-fitting pieces stick or pushing the envelope of temperature (cold)
on the glue.
--
dpb wrote:
> Tanus wrote:
> ...
>> The other day I went to the kindling pile to get some wood for
>> turning a knob. I didn't have the size I needed, so I decided to
>> take 2 pieces and face-glue them together to give me the thickness
>> I
>> needed. I'm fairly sure the pieces were walnut. The glue was
>> Titebond III
>>
>> The first two pieces fell apart by hand. I was in a hurry and used
>> weak clamps. I also didn't wait long enough for the glue to bond.
>
> Well, that's obvious enough...
>
>> The second two pieces went better but fell apart when I was turning
>> on the lathe. Same for the third set. Both of the second sets had
>> much stronger clamps and I waited a full day.
>>
>> In all cases, the faces were flat and smooth, planed by hand.
>>
>> What am I doing wrong?
>
> I don't really have a clue -- a glue joint of that type should be
> possible to make hold stronger than the wood itself simply w/ a "rub
> fit" even w/o clamping at all.
>
> I have only a few guesses (and they're all simply that w/ no more
> data
> or observation)...
>
> 1. The source of the material from the woodpile makes me
> wonder--was
> this dry lumber or scrap firewood that could possibly be wet? Seems
> unlikely, but we're searching here...
>
> 2. The glue is old or your simply not using sufficient amount to
> get
> good glue surface. Since same symptom w/ "weak" or "stronger"
> clamps,
> I'm assuming you're not clamping to the point of glue starvation,
> but
> that's another possibility.
>
> 3. Surfaces aren't very flat or are excessively burnished so no
> porosity for glue. Would be very difficult w/ walnut given it's
> open-pored characteristics but again...
>
> I can think of very few glue joints that didn't hold ever over 30
> years and virtually all of them could be attributed to either trying
> to make ill-fitting pieces stick or pushing the envelope of
> temperature (cold) on the glue.
Too much pressure will result in a glue-starved joint. I think many
people go overboard on the clamping pressure with Titebond and the
like.
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
[email protected] wrote:
>> Too much pressure will result in a glue-starved joint.
>
> I read some research that proved this to be an old wives tale. Joints
> can be glue starved, BUT not at the pressure generated by hand clamps.
> The study was scientifically done and reported in a woodworking mag.
That would have been Fine Woodworking (about 3-4 issues ago?).
Pretty incredible recommendations in it--if followed, we'd all need
hydraulic presses to meet the "optimum" clamping pressures... :)
Fortunately, experience has shown that far less clamping pressure than
those determined by the research reported therein is adequate for highly
reliable joints.
The likelihood of glue starvation by clamping pressure would be quite
low for OP's case I would think except for two possibilities that seem
present in his case--possibly not using sufficient to start with and a
small glue joint area means clamp pressure is concentrated and if he was
concerned in not clamping enough, could possibly have really torqued
down. Don't know what kind of clamps were used, either, of course...
The possibility posted elsewhere of the glue having been subject to
freezing over the winter is a most excellent one I hadn't thought
of...that would do it.
--
[email protected] wrote:
>> Too much pressure will result in a glue-starved joint.
>
> I read some research that proved this to be an old wives tale.
> Joints
> can be glue starved, BUT not at the pressure generated by hand
> clamps.
> The study was scientifically done and reported in a woodworking mag.
For certain values of "scientifically". And hardly "old wives tale"
when the glue manufacturers agree with years of serious research by
the likes of Forest Products Laboratories that for each type of glue
there is an optimal glue line thickness, the achievement of which
depends on the type of wood, the grain orientation, the viscosity of
the glue, and the clamping pressure.
As for "the pressure generated by hand clamps", how much pressure is
that? That depends on the joint geometry. Don't confuse "force" with
"pressure".
One test reported in the popular press is not definitive research.
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Chris Friesen wrote:
> J. Clarke wrote:
>
>> For certain values of "scientifically". And hardly "old wives
>> tale"
>> when the glue manufacturers agree with years of serious research by
>> the likes of Forest Products Laboratories that for each type of
>> glue
>> there is an optimal glue line thickness, the achievement of which
>> depends on the type of wood, the grain orientation, the viscosity
>> of
>> the glue, and the clamping pressure.
>
> Yep. And for hard maple and PVA the optimal glue line thickness
> resulted from very high pressures...substantially more than the
> 250psi
> that is at the upper end of Franklin's recommendations.
If one needs "very high pressures" to achieve 3-6 mil bond line
thickness then one is applying too much glue. Note that the table of
"recommended clamping pressures" in the Roman Rablej article in Fine
Woodworking appears to have been pulled out of Rablej's ass. He gives
no source for it at all.
> However, as "dpb" mentioned, optimal is not normally necessary, and
> quite adequate joints can be made at much lower pressure.
Which is beside the point.
>> As for "the pressure generated by hand clamps", how much pressure
>> is
>> that? That depends on the joint geometry. Don't confuse "force"
>> with "pressure".
>
> Absolutely true. Common misconception.
>
> Chris
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Chris Friesen wrote:
> J. Clarke wrote:
>
>> If one needs "very high pressures" to achieve 3-6 mil bond line
>> thickness then one is applying too much glue. Note that the table
>> of
>> "recommended clamping pressures" in the Roman Rablej article in
>> Fine
>> Woodworking appears to have been pulled out of Rablej's ass. He
>> gives no source for it at all.
>
> It may not be the case that a 3-6 mil thickness is always ideal.
Do you have evidence that it is not?
> If
> so,
> then higher pressures may be better.
How about just applying the right thickness to begin with instead of
glomming it on and trying to squeeze it out with clamps?
> As "dpb" mentioned in this newsgroup when the FWW article came out,
> I'd
> guess the pressures came from Rabiej's paper:
>
> "The Effect of Clamping Pressure and Orthotropic Wood Structure on
> the
> Strength of Glued Bonds", Wood and Fiber Science Vol. 24, No. 3,
> July
> 1992.
>
> From the abstract at
> "http://swst.metapress.com/content/1050536165217317/?p=8b5006db06be4640acd2801679e46c4e&pi=3"
>
> "...Using this concept, the optimum clamping pressure for sugar
> maple
> was found to be 0.3 times compression strength using U-F glue and
> 0.5
> times using PVAc glue. This approach to determining reliable
> clamping
> pressure data can lead to improved gluing practice and more precise
> testing procedures."
>
> Using the FPL tables, this gives a bit over 700psi for PVA glue.
But (a) how much difference does he see (I'm not really interesting in
paying 25 bucks to find out) and (b) has anybody replicated his
results?
Personally I'll take FPL's recommendations based on decades of
experience backed by research over one unreplicated paper.
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
J. Clarke wrote:
> Chris Friesen wrote:
>> J. Clarke wrote:
>>
>>> If one needs "very high pressures" to achieve 3-6 mil bond line
>>> thickness then one is applying too much glue. Note that the table
>>> of
>>> "recommended clamping pressures" in the Roman Rablej article in
>>> Fine
>>> Woodworking appears to have been pulled out of Rablej's ass. He
>>> gives no source for it at all.
>> It may not be the case that a 3-6 mil thickness is always ideal.
>
> Do you have evidence that it is not?
>
>> If
>> so,
>> then higher pressures may be better.
>
> How about just applying the right thickness to begin with instead of
> glomming it on and trying to squeeze it out with clamps?
>
>> As "dpb" mentioned in this newsgroup when the FWW article came out,
>> I'd
>> guess the pressures came from Rabiej's paper:
>>
>> "The Effect of Clamping Pressure and Orthotropic Wood Structure on
>> the
>> Strength of Glued Bonds", Wood and Fiber Science Vol. 24, No. 3,
>> July
>> 1992.
>>
>> From the abstract at
>> "http://swst.metapress.com/content/1050536165217317/?p=8b5006db06be4640acd2801679e46c4e&pi=3"
>>
>> "...Using this concept, the optimum clamping pressure for sugar
>> maple
>> was found to be 0.3 times compression strength using U-F glue and
>> 0.5
>> times using PVAc glue. This approach to determining reliable
>> clamping
>> pressure data can lead to improved gluing practice and more precise
>> testing procedures."
>>
>> Using the FPL tables, this gives a bit over 700psi for PVA glue.
>
> But (a) how much difference does he see (I'm not really interesting in
> paying 25 bucks to find out) and (b) has anybody replicated his
> results?
>
> Personally I'll take FPL's recommendations based on decades of
> experience backed by research over one unreplicated paper.
The guy is a prof in industrial processes at a university w/, it
appears, something like 20 years or so of experience and a fairly long
list of published and contract works from various sources including FPL
and wood manufacturing businesses. From that, I would presume his work
has been considered valuable or he wouldn't continue to hold the
position and find clients.
OTOH, it does appear that his work is mostly for large, automated
industrial processes so that I think his results aren't of great import
to most small shops or individuals as is the general readership of r.w
nor do I think most of FWW's readership is of the same type/style of
manufacturing as that to which his research is/was directed.
--
Leon wrote:
>
> Well, Walnut has nothing to do with it. The glue may not be fully cured and
> with a joint spinning and pulling it could fail if not properly cured.
> Walnut is NOT incredibly strong, did the joint fail or did the wood fail
> close to the joint?
>
>
Sorry guys.I should have given more information.
All joints failed at the glue. In other words, the pieces pretty much
fell apart with no wood breaking.
The glue hasn't frozen but it has been cold. I've used the glue recently
and it's worked fine. Although I keep the glue in an unheated shop, the
cabinet it's stored in is heated throughout the winter. Buying new glue
is what I'll do next.
I liked the idea of staving the joint until more than a few of you said
that likely wasn't the case, which is bringing me back to bad glue.
The faces were hand planed and very smooth to the touch. No sanding
after planing. I squeezed the glue in a zig zag along both surfaces and
then smoothed with a finger so the glue was even on both.
There is some doubt in my mind about the wood being walnut. I'll verify
that later. However, the wood from the kindling pile was very dry. I get
my kindling from a cabinet shop locally, and store it in a shed before
and after sawing it to length.
I'll get some more glue and try this thing again. In the interim, I made
my knobs from other stock, but this idea of glue failing is not one I
want to repeat.
Thanks all of you for the replies. I didn't think this was going to
generate so much. I'm glad I asked.
Tanus
Lew Hodgett wrote:
> "Tanus" <[email protected]> wrote:
>
>
>> What am I doing wrong?
>
> Remember your experience with epoxy?
>
> Patience is a virtue.
>
> Neither epoxy or TiteBond like cold weather or being put to work
> before they are ready.
>
>
> Lew
>
>
LOL. Lew, you have a memory like my wife's. What's worse, you and she
are right way too many times.
But, you have a point. The epoxy failed the first time precisely because
of the cold. This time, I really dunno. I'll get some new glue and give
it another whirl.
Tanus
Lew Hodgett wrote:
> "Tanus" wrote:
>
>> LOL. Lew, you have a memory like my wife's. What's worse, you and
>> she are right way too many times.
>>
>> But, you have a point.
>
> I know, but I comb my hair so it covers it<G>
>
>> I'll get some new glue and give it another whirl.
>
>
> Why not use the epoxy you already have?
It's old by now, too? :)
--
Kenneth wrote:
> On Tue, 27 May 2008 18:33:50 -0400, Tanus
> <[email protected]> wrote:
>
>> The glue hasn't frozen but it has been cold. I've used the glue recently
>> and it's worked fine. Although I keep the glue in an unheated shop, the
>> cabinet it's stored in is heated throughout the winter. Buying new glue
>> is what I'll do next.
>
> Howdy,
>
> 'Just curious...
>
> How do you heat the cabinet?
>
> Thanks,
Hi Ken,
I can't remember what these things are called, but they're sold as
copper line heaters to prevent the water line from freezing. I got mine
at the Borg. 120 volt with a simple bimetallic strip thermostat. They
look like extension cords and give off enough heat to keep the line from
freezing but are not too hot to handle with bare hands. Lengths vary
from 6' to 25' or more.
I've lined a cupboard with Styrofoam SM and put a couple of these line
heaters around the perimeter. It keeps the cabinet warm enough for my
glues, water stones and anything else I need to keep from freezing. The
rest of the shop can get down to about -30° C but the cabinet stays
above freezing.
Tanus
Tanus wrote:
...
> ... I'll get some new glue and give
> it another whirl.
Out of (more or less idle) curiosity, any idea how old what you used
actually is? IIRC, a year is the suggested shelf life for TB III, but
I've seen no change in gluing properties of that kept far longer.
It does tend to thicken somewhat and get stringy, but as noted on the
container, a jarring of the container (not stirring, but vibrating) will
reconstitute its properties unless it is, indeed, too far gone. (It's a
very unusual-behaving material in that regard; I've never observed a
similar characteristic in any other material).
Also iirc, the chalk temperature is 47 F, so if it is cool at night yet
still above freezing, even if the glue is warm enough being stored in
the heated cabinet, if the wood is colder than that, it will cool the
glue and the result could be the failure of the type you observe. Does
the glue surface appear to be dry and chalky after the failures? If so,
that would be a very suggestive indicator of low temperature. I had
forgotten to mention the wood temperature as well as glue before.
--
dpb wrote:
> Tanus wrote:
> ....
>> ... I'll get some new glue and give it another whirl.
>
> Out of (more or less idle) curiosity, any idea how old what you used
> actually is? IIRC, a year is the suggested shelf life for TB III, but
> I've seen no change in gluing properties of that kept far longer.
>
> It does tend to thicken somewhat and get stringy, but as noted on the
> container, a jarring of the container (not stirring, but vibrating) will
> reconstitute its properties unless it is, indeed, too far gone. (It's a
> very unusual-behaving material in that regard; I've never observed a
> similar characteristic in any other material).
>
> Also iirc, the chalk temperature is 47 F, so if it is cool at night yet
> still above freezing, even if the glue is warm enough being stored in
> the heated cabinet, if the wood is colder than that, it will cool the
> glue and the result could be the failure of the type you observe. Does
> the glue surface appear to be dry and chalky after the failures? If so,
> that would be a very suggestive indicator of low temperature. I had
> forgotten to mention the wood temperature as well as glue before.
>
> --
I bought my current Titebond in early 2008, Jan or Feb. All temps, glue,
wood and environment,
were above 60 when the glueing was done, but overnite temps may have
dipped into the 40s. I bring glueups into the house in the winter, but
don't in spring/summer. This piece was so small, it would have been easy
to bring it inside to cure overnite, but it never entered my mind.
You may have something here.
I"m still going to get new glue.
Lew Hodgett wrote:
> "Tanus" wrote:
>
>> LOL. Lew, you have a memory like my wife's. What's worse, you and
>> she are right way too many times.
>>
>> But, you have a point.
>
> I know, but I comb my hair so it covers it<G>
>
>> I'll get some new glue and give it another whirl.
>
>
> Why not use the epoxy you already have?
>
> Lew
>
>
>
I could have. That epoxy is stored inside and I'm sure it's fine. It's
also expensive as hell, and I don't want to use it for ordinary
glue-ups. I'm certainly a convert, Lew. The stuff is amazing in
tough-to-fix jobs, but for this, if I had considered it, would have
seemed a waste. I'm also sure that it would have worked well.
Tanus
rich wrote:
...
> In the OP, the one thing I noticed was the lack of time between gluing
> and working. I think the Titebond label says something like "sets in
> 30 mins, full strength in 24 hours." I always wait 'bout an hour to
> unclamp, then overnight before I trust the joint. And if I don't need
> the clamps right away, they usually remain clamped overnight.
>
> I think all of the above suggestions have merit, but the big factor
> would seem to be the time between gluing and working.
>
> Hope this helps.....
Quite possibly the key, particularly if it was cool as appears may have
been from followup. TB III is slower-drying than either I or II which
has advantages, but it does require longer before working. I guess I
may have overlooked that detail in initial reading.
--
Peter Huebner wrote:
> In article <bWR_j.5654$u7.3933@trnddc07>, [email protected]
> says...
>>> What am I doing wrong?
>> Hard to say but it is obvious that either your glue is no good or the wood
>> surfaces being glued were "dirty". I suspect the latter.
>>
>> Was the "kindling pile" inside or outside? Did you machine or sand the wood
>> surfaces to be glued so that you had nice fresh, dry, unoxidized,
>> unweathered wood for the glue?
>>
>
> My first thought at that sort of spectacular glue failure would
> be 'wet wood'. Wet is not always obvious, but wood above a
> certain moisture content does not seem to bond well with any
> waterbased glues that I've used (I haven't used titebond, since
> it's not commonly sold in these parts; but I understand it to
> be a member of the 'white glue'/pva/aliphatic family, also).
>
> -P.
>
It is in that family. And I'd tend to agree, but this wood was tinder
dry. I"m still not sure what the issue was here. I've not had a chance
to glue anymore of it, but will let you guys know when I do.
Tanus
Tanus <[email protected]> wrote:
> The faces were hand planed and very smooth to the touch. No sanding
> after planing. I squeezed the glue in a zig zag along both surfaces and
> then smoothed with a finger so the glue was even on both.
^^^^^^
Using your finger to smear the glue might have something to do with
your problem. It could be that whatever oils are on your hand don't
mix with the glue. Try using an acid brush to smooth the glue around
next time and see if that makes any difference.
[1]: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41338
--
If you want to reply via email, change the obvious words to numbers and
remove ".invalid".
"Tanus" <[email protected]> wrote in message news:[email protected]...
> I've done a bit of glue-ups. Most have been successful. Some have been
> disastrous, but with each failure, I've been able to figure out what I did
> wrong and not repeat it too many times. All have been with pine, maple, or
> oak.
>
> At this point, the glue-ups I find easiest to do are laminations or edge
> gluing. If the surfaces are clean and planed smooth, and the clamping
> pressure is enough, the joint will hold for me.
>
> The other day I went to the kindling pile to get some wood for turning a
> knob. I didn't have the size I needed, so I decided to take 2 pieces and
> face-glue them together to give me the thickness I needed. I'm fairly sure
> the pieces were walnut. The glue was Titebond III
>
> The first two pieces fell apart by hand. I was in a hurry and used weak
> clamps. I also didn't wait long enough for the glue to bond.
>
> The second two pieces went better but fell apart when I was turning on the
> lathe. Same for the third set. Both of the second sets had much stronger
> clamps and I waited a full day.
>
> In all cases, the faces were flat and smooth, planed by hand.
>
> What am I doing wrong?
>
> Tanus
Well, Walnut has nothing to do with it. The glue may not be fully cured and
with a joint spinning and pulling it could fail if not properly cured.
Walnut is NOT incredibly strong, did the joint fail or did the wood fail
close to the joint?