Araldite or wood glue ?

[JimT]

Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.

Many thanks

JimT

[Mattia Valente]

Post by JimT
Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.

Um, I wouldn't want to even consider using epoxy on something that will
be taking string tension. Most of the stuff I've used, and particularly
Araldite, isn't that strong, often stays a bit gummy, and may very well
creep under tension. In addition, you want a good strong wood-wood joint
for the bridge, and really don't want any gaps in there. The bridge
footprint isn't that huge, and you want good, full contact between the
surfaces.

If you can't flatten the bridge by heating, clamping, whatever, then
consider biting the bullet, sanding through the decorative stuff,
replacing it (if it's a veneer or veneer sandwich, it can't be that
complicated to do). I wouldn't sacrifice looks for structure, ever.

Mattia

[JimT]

On Thu, 16 Sep 2004 19:15:42 +0200, Mattia Valente

Post by Mattia Valente
Um, I wouldn't want to even consider using epoxy on something that will
be taking string tension. Most of the stuff I've used, and particularly
Araldite, isn't that strong, often stays a bit gummy, and may very well
creep under tension.

HI Mattia, I've heard a few arguments against Araldite before, but
never the ones you cited. I think Araldite is an extremely strong
adhesive for many applications.

Post by Mattia Valente
In addition, you want a good strong wood-wood joint
for the bridge, and really don't want any gaps in there. The bridge
footprint isn't that huge, and you want good, full contact between the
surfaces.

I would get that, using Araldite. But whether its the best choice of
adhesive is still in question. Someone else suggested Cascamite
(formaldehide glue?) mixed with sawdust...

Post by Mattia Valente
If you can't flatten the bridge by heating, clamping, whatever, then
consider biting the bullet, sanding through the decorative stuff,
replacing it (if it's a veneer or veneer sandwich, it can't be that
complicated to do).

I guess a skilled wood carver could replace it; but I don't posess
that skill nor the time required to do it.

Post by Mattia Valente
I wouldn't sacrifice looks for structure, ever.

Nor would I on a modern instrument, I guess. However this is an
antique instrument and I don't want to start replacing parts with
non-original ones. I have no qualms about using modern adhesives
though, since they won't be visible.

Jim T

[Mattia Valente]

Post by JimT
On Thu, 16 Sep 2004 19:15:42 +0200, Mattia Valente

Post by Mattia Valente
Um, I wouldn't want to even consider using epoxy on something that will
be taking string tension. Most of the stuff I've used, and particularly
Araldite, isn't that strong, often stays a bit gummy, and may very well
creep under tension.

HI Mattia, I've heard a few arguments against Araldite before, but
never the ones you cited. I think Araldite is an extremely strong
adhesive for many applications.

OK, possibly being overdramatic a bit ;-)

The 'gummy' is probably my less-than-perfect measuring and mixing
skills. By 'isn't that strong' I mean for wood-wood joints: wood glues
will give you a better joint, and the creep is a fairly commonly cited
effect. I've only use epoxy for non-wood to wood joints (carbon fibre,
inlay materials) and it works well there, although I've switched to
Polyutherane and CA, respectively.

Post by JimT

Post by Mattia Valente
In addition, you want a good strong wood-wood joint
for the bridge, and really don't want any gaps in there. The bridge
footprint isn't that huge, and you want good, full contact between the
surfaces.

I would get that, using Araldite. But whether its the best choice of
adhesive is still in question. Someone else suggested Cascamite
(formaldehide glue?) mixed with sawdust...

Additional issue: It's a bridge, it may very well need removing and
replacing at some point in the future. Epoxy makes that a bit more
difficult. Again, while you're filling the gaps, the glue's bonding to
itself isn't as strong as wood-wood bonding. You won't get an optimum
grab, possibly slightly better than unfilled gaps, though.

Post by JimT

Post by Mattia Valente
If you can't flatten the bridge by heating, clamping, whatever, then
consider biting the bullet, sanding through the decorative stuff,
replacing it (if it's a veneer or veneer sandwich, it can't be that
complicated to do).

I guess a skilled wood carver could replace it; but I don't posess
that skill nor the time required to do it.

Tried heating and clamping flat? It can work.

Post by JimT

Post by Mattia Valente
I wouldn't sacrifice looks for structure, ever.

Nor would I on a modern instrument, I guess. However this is an
antique instrument and I don't want to start replacing parts with
non-original ones. I have no qualms about using modern adhesives
though, since they won't be visible.

Yes, but they will affect it's later value and repairability. I'd
personally be tempted to stick with Hide Glue for work on antiques. Or
rather, send it to someone with more experience with antiques, 'cause I
don't have enough repair experience to trust myself with the stuff.

Mattia

[Jake]

On Fri, 17 Sep 2004 09:09:14 +0200, Mattia Valente

Post by Mattia Valente

Post by JimT
On Thu, 16 Sep 2004 19:15:42 +0200, Mattia Valente

Post by Mattia Valente
Um, I wouldn't want to even consider using epoxy on something that will
be taking string tension. Most of the stuff I've used, and particularly
Araldite, isn't that strong, often stays a bit gummy, and may very well
creep under tension.

HI Mattia, I've heard a few arguments against Araldite before, but
never the ones you cited. I think Araldite is an extremely strong
adhesive for many applications.

OK, possibly being overdramatic a bit ;-)
The 'gummy' is probably my less-than-perfect measuring and mixing
skills.

You certainly must have been doing something *very* wrong! Sounds more
like you forgot to add any hardner at all! The ratio of hadner to
resin doesn't need to be "perfect". If it's even close, the joint
between wood and wood, will be stronger than the wood itself, in every
case I've ever known.

Jake

[Mattia Valente]

Post by Jake
On Fri, 17 Sep 2004 09:09:14 +0200, Mattia Valente

Post by Mattia Valente
OK, possibly being overdramatic a bit ;-)
The 'gummy' is probably my less-than-perfect measuring and mixing
skills.

You certainly must have been doing something *very* wrong! Sounds more
like you forgot to add any hardner at all! The ratio of hadner to
resin doesn't need to be "perfect". If it's even close, the joint
between wood and wood, will be stronger than the wood itself, in every
case I've ever known.

Well, no. I've used it for inlay, and it dries hard, but not as brittly
hard as titebond does. It's just..different.

We're talking about an imperfect joint here, thought, where the
comparison to a nicely mated test piece doesn't quite apply. You gotta
compare equivalent situations.

Mattia

[Jens]

Post by Mattia Valente

Post by JimT
Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.

Um, I wouldn't want to even consider using epoxy on something that will
be taking string tension. Most of the stuff I've used, and particularly
Araldite, isn't that strong, often stays a bit gummy, and may very well
creep under tension. In addition, you want a good strong wood-wood joint
for the bridge, and really don't want any gaps in there. The bridge
footprint isn't that huge, and you want good, full contact between the
surfaces.
If you can't flatten the bridge by heating, clamping, whatever, then
consider biting the bullet, sanding through the decorative stuff,
replacing it (if it's a veneer or veneer sandwich, it can't be that
complicated to do). I wouldn't sacrifice looks for structure, ever.
Mattia

I'm no expert, but on my first, and only, home made solid body mahogany
set-neck guitar, I used rapid epoxy for the neck joint. The reason was that
I couldn't make the joint a complete fit - I did the tap and pocket as good
as possiple with a wood chisel and used a couple of wood slices to fill the
worst gabs. The expoxy did the job very well - no shrink and it's as strong
as the wood it self (I did an experiment on same kind of wood and when
putting force to the joint, the wood cracked - not the glue-joint). The use
of wood glue requires a perfect fit of the two pieces of wood as it will
shrink.

My guitar is now three years old and is 100% stable regarding tuning - so
the neck joint is perfect.

One drawback is of cause that it cannot be dismantled again.

Rgds

Jens

[JimT]

Post by Jens
I'm no expert, but on my first, and only, home made solid body mahogany
set-neck guitar, I used rapid epoxy for the neck joint. The reason was that
I couldn't make the joint a complete fit - I did the tap and pocket as good
as possiple with a wood chisel and used a couple of wood slices to fill the
worst gabs. The expoxy did the job very well - no shrink and it's as strong
as the wood it self (I did an experiment on same kind of wood and when
putting force to the joint, the wood cracked - not the glue-joint). The use
of wood glue requires a perfect fit of the two pieces of wood as it will
shrink.
My guitar is now three years old and is 100% stable regarding tuning - so
the neck joint is perfect.
One drawback is of cause that it cannot be dismantled again.

Hi Jens,
Thank you for your input. What you said is encouraging! Looks like I
might use epoxy, then.

Rgards,
JimT

[Mattia Valente]

Post by Jens
I'm no expert, but on my first, and only, home made solid body mahogany
set-neck guitar, I used rapid epoxy for the neck joint. The reason was that
I couldn't make the joint a complete fit - I did the tap and pocket as good
as possiple with a wood chisel and used a couple of wood slices to fill the
worst gabs. The expoxy did the job very well - no shrink and it's as strong
as the wood it self (I did an experiment on same kind of wood and when
putting force to the joint, the wood cracked - not the glue-joint). The use
of wood glue requires a perfect fit of the two pieces of wood as it will
shrink.
My guitar is now three years old and is 100% stable regarding tuning - so
the neck joint is perfect.

I'm sure it is.

A neck joint is a completely different kind of joint, under totally
different stresses, and even if gaps are filled with glue, there's wood
pushing against wood in the direction most of the tension's going and in
several others to boot. It's in a neck pocket, and it's the sections
where the gaps not too huge that are bearing the load. Neck joints also
have a relatively large amount of glue surface area to deal with the
tension in addition to the mechanical support. There's absolutely
nowhere for the neck to creep to, so for a set neck joint, it's a fine
option. String tension is trying to shear the bridge in the direction of
string tension, and the glue joint, the bonded wood, is what's
preventing that. It's like gluing a neck onto a board, with no tenon.

Epoxy will adhere to itself, unlike hide or titebond, and thus fill
gaps. It's less strong if it's filling gaps than if you've got a good
fit; so if you test the glue on a tight-fitting joint, it's really not
translateable to a gappy joint. We're also talking about the creep
factor: whether it'll move under constant (high) tension, over time.
I've read enough reports of epoxy doing that that I believe it.

Post by Jens
One drawback is of cause that it cannot be dismantled again.

Always can be. Most epoxies do release with enough heat. Enough people
use epoxy for fingerboards without problems. Certainly not the easiest
way to do things, but in theory it could be done.

Mattia

[Clifford Heath]

Araldite... often stays a bit gummy

All epoxies are like that if the mixing ratio is imperfect.
The reaction is stochiometric, so any extra part A or part B
remains unreacted. Could that explain your experience?

[Mattia Valente]

Post by Clifford Heath

Araldite... often stays a bit gummy

All epoxies are like that if the mixing ratio is imperfect.
The reaction is stochiometric, so any extra part A or part B
remains unreacted. Could that explain your experience?

With Araldite, it's limited to inlay, to be honest. Never quite seemed
to get as rock hard as dry titebond does. I know the kind in those
two-in-one syringes. For structural work, I'd want to invest in a better
epoxy and measuring system (System 3 by West or something like that).
But I still wouldn't want to use it for a bridge.

Mattia

[Jake]

Post by JimT
Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.
Many thanks
JimT

Look at:

http://www.frets.com/FRETSPages/Luthier/Data/Materials/gluechart.html

Jake

[Mattia Valente]

Post by Jake
http://www.frets.com/FRETSPages/Luthier/Data/Materials/gluechart.html

Trust Frank Ford. He's the repair wise man of them all.

Note Epoxy and CA listed as 'OK', hide glue as 'best' and yellow glue as
'good' for bridge gluing repairs. Note the section that mentions epoxy
losing strengths at temperatures reached in parked cars, and not being
the best choice for stressed applicaitions such as birdge/neck.

For me, for a bridge, I'd want a good, positive tight fit, regardless of
the glue used.

Mattia

[Jim T]

On Fri, 17 Sep 2004 14:15:04 +0200, Mattia Valente

Post by Mattia Valente

Post by Jake
http://www.frets.com/FRETSPages/Luthier/Data/Materials/gluechart.html

Trust Frank Ford. He's the repair wise man of them all.
Note Epoxy and CA listed as 'OK', hide glue as 'best' and yellow glue as
'good' for bridge gluing repairs. Note the section that mentions epoxy
losing strengths at temperatures reached in parked cars, and not being
the best choice for stressed applicaitions such as birdge/neck.
For me, for a bridge, I'd want a good, positive tight fit, regardless of
the glue used.
Mattia

I've heard a few people say they recommend the old traditional hide
glue for bridges. But that is the one glue I've seen pull apart at the
bridge without damaging the wood! And both pieces (the bridge and the
top) were well-scored to maximise adhesion. After seing that, I'm more
inclined to use ordinary white glue for a bridge. Especially now that
I've succeeded in flattening the bottom. The secret there was to
flatten the main part of the bridge while the two protruding fancy
ends were left untouched. That's OK because those buts can flex
downwards when gluing takes place. Everyone tells me that everyday
white wood glue makes a stronger joint than the sood ityself, so what
more could I ask for?

Jim T

[Mattia Valente]

Post by Jim T
I've heard a few people say they recommend the old traditional hide
glue for bridges. But that is the one glue I've seen pull apart at the
bridge without damaging the wood! And both pieces (the bridge and the
top) were well-scored to maximise adhesion.

Um, that might be the problem then. Hide glue is unforgiving; it
requires a perfect fit, clean, scraped or planed surfances are ideal.
Scoring's not gonna help any. Hide glue's got the history to prove it'll
do the job; none of the other adhesives we use have been around for
centuries.

Post by Jim T
After seing that, I'm more
inclined to use ordinary white glue for a bridge. Especially now that
I've succeeded in flattening the bottom. The secret there was to
flatten the main part of the bridge while the two protruding fancy
ends were left untouched. That's OK because those buts can flex
downwards when gluing takes place. Everyone tells me that everyday
white wood glue makes a stronger joint than the sood ityself, so what
more could I ask for?

I'd go with that. Although I'd reccomend yellow glue (titebond,
original, not II) over white. It's my number 1 used woodworking glue,
and works just great.

Mattia

[Jim T]

On Fri, 17 Sep 2004 20:04:46 +0200, Mattia Valente

Post by Mattia Valente
I'd go with that. Although I'd reccomend yellow glue (titebond,
original, not II) over white. It's my number 1 used woodworking glue,
and works just great.

Thanks for the tip. I'll try some of that next time I buy glue.

Jim T

[Cyberserf]

Post by Jim T
On Fri, 17 Sep 2004 14:15:04 +0200, Mattia Valente

Post by Mattia Valente

Post by Jake
http://www.frets.com/FRETSPages/Luthier/Data/Materials/gluechart.html

Trust Frank Ford. He's the repair wise man of them all.
Note Epoxy and CA listed as 'OK', hide glue as 'best' and yellow
glue as 'good' for bridge gluing repairs. Note the section that
mentions epoxy losing strengths at temperatures reached in parked
cars, and not being the best choice for stressed applicaitions such
as birdge/neck.
For me, for a bridge, I'd want a good, positive tight fit,
regardless of the glue used.
Mattia

I've heard a few people say they recommend the old traditional hide
glue for bridges. But that is the one glue I've seen pull apart at the
bridge without damaging the wood! And both pieces (the bridge and the
top) were well-scored to maximise adhesion. After seing that, I'm more
inclined to use ordinary white glue for a bridge. Especially now that
I've succeeded in flattening the bottom. The secret there was to
flatten the main part of the bridge while the two protruding fancy
ends were left untouched. That's OK because those buts can flex
downwards when gluing takes place. Everyone tells me that everyday
white wood glue makes a stronger joint than the sood ityself, so what
more could I ask for?
Jim T

It will do that if exposed to high heat...but then, it's very easy to clean
the surfaces and reaply the bridge...nope, sorry, you'll never turn me off
wood glue...I've seen it work for too long and there is museum evidence of
wood glue joints thousands of years old (on egyptian furniture IIRC).

White glue (white PVA) is good for paper. For wood, you need carpenter
quality yellow PVA (Titebond is tried and true)...that joint is stronger
than the wood (as is hide glue), unless the glue is stressed beyond it's
specifications, for Yellow PVA and Hide Glue, with abundant moisture or heat
(that's at about 140F-160F...so we are talking, the enterior of a car in
summer or too close to the campfire for too long...not your everyday
comfortable, wish I had a beer, temperature).

-CS

[Cyberserf]

Post by Cyberserf

Post by Jim T
On Fri, 17 Sep 2004 14:15:04 +0200, Mattia Valente

Post by Mattia Valente

Post by Jake
http://www.frets.com/FRETSPages/Luthier/Data/Materials/gluechart.html

Trust Frank Ford. He's the repair wise man of them all.
Note Epoxy and CA listed as 'OK', hide glue as 'best' and yellow
glue as 'good' for bridge gluing repairs. Note the section that
mentions epoxy losing strengths at temperatures reached in parked
cars, and not being the best choice for stressed applicaitions such
as birdge/neck.
For me, for a bridge, I'd want a good, positive tight fit,
regardless of the glue used.
Mattia

I've heard a few people say they recommend the old traditional hide
glue for bridges. But that is the one glue I've seen pull apart at
the bridge without damaging the wood! And both pieces (the bridge
and the top) were well-scored to maximise adhesion. After seing
that, I'm more inclined to use ordinary white glue for a bridge.
Especially now that I've succeeded in flattening the bottom. The
secret there was to flatten the main part of the bridge while the
two protruding fancy ends were left untouched. That's OK because
those buts can flex downwards when gluing takes place. Everyone
tells me that everyday white wood glue makes a stronger joint than
the sood ityself, so what more could I ask for?
Jim T

It will do that if exposed to high heat...but then, it's very easy to
clean the surfaces and reaply the bridge...nope, sorry, you'll never
turn me off wood glue...I've seen it work for too long and there is
museum evidence of wood glue joints thousands of years old (on
egyptian furniture IIRC).

Crap...dunno what I'm thinking, that was supposed to be an impassioned plea
for Hide Glue...please replace all mentions of "wood" glue (whatever that
means) in the above paragraph with Hide glue.

Cheers, CS

[Cyberserf]

Post by JimT
Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.
Many thanks
JimT

Jim,

My 2 cents worth, and perhaps these have been mentioned. Notwithstanding
creep and other issues, Araldite is an epoxy...epoxies are hard to clean
once applied...it's a lifetime thing. Bridges sometimes need repair.
Araldite, as an adhesive, will make that process more difficult than
bnecessary. Wood glue (Yellow PVA, aka Aliphatic Resin) is easy to clean and
easy to use...it works and that's why it has replaced, in many luthery
applications, the more traditional hide glue (which is truly the best in my
books). Frankly I ask myself, when you already have a solution that is
already proven effective and easy to use, why mess with tradition? So, out
of curiosity, what are the perceived benefits of Araldite?

True, Wood glue and hide glue are not typically "great" gap filler and, if
you have large voids, perhaps you should mix a bit up with some sawdust with
the glue to even the surface. Conversely, if you have a perverse affinity to
epoxy, use some putty epoxy (Qwik wood comes to mind) to fill in the gaps
and build up an even surface (it sands super nice), then use wood glue
(Titebond or some such) to secure the bridge to the top.

Again, just my .02 worth...I haven't followed the whole thread so have no
idea if I am repeating the obvious.

Cheers, CS

[Jim T]

On Fri, 17 Sep 2004 15:49:47 -0400, "Cyberserf"

Post by Cyberserf

Post by JimT
Can anyone tell me if Araldite would be as strong as wood glue for the
following application? It's a lguitar restoration job; I need to glue
a rosewood bridge onto the spruce top. Why am I
thinking of using Araldite, instead of wood glue?... The bridge is
somewhat distorted, i.e., not flat on the bottom, whereas the top of
the instrument is almost flat. If I use araldite, the glue will fill
out the spaces betwen the warped bridge and the top's surface, whereas
wood glue won't. Wood glue shrinks as it dries out and therefore won't
fill out those spaces. I can't sand the bottom of the bridge flat
because there's a thin decirative bit protruding from each end.
Sanding the bottom flat would effectively mean sanding right through
those bits.
Many thanks
JimT

Jim,
My 2 cents worth, and perhaps these have been mentioned. Notwithstanding
creep and other issues, Araldite is an epoxy...epoxies are hard to clean
once applied...it's a lifetime thing. Bridges sometimes need repair.
Araldite, as an adhesive, will make that process more difficult than
bnecessary. Wood glue (Yellow PVA, aka Aliphatic Resin) is easy to clean and
easy to use...it works and that's why it has replaced, in many luthery
applications, the more traditional hide glue (which is truly the best in my
books). Frankly I ask myself, when you already have a solution that is
already proven effective and easy to use, why mess with tradition? So, out
of curiosity, what are the perceived benefits of Araldite?
True, Wood glue and hide glue are not typically "great" gap filler and, if
you have large voids, perhaps you should mix a bit up with some sawdust with
the glue to even the surface. Conversely, if you have a perverse affinity to
epoxy, use some putty epoxy (Qwik wood comes to mind) to fill in the gaps
and build up an even surface (it sands super nice), then use wood glue
(Titebond or some such) to secure the bridge to the top.
Again, just my .02 worth...I haven't followed the whole thread so have no
idea if I am repeating the obvious.
Cheers, CS

CS,
Thanks for your suggestions. I ended up doing it with white wood glue.
That was before I read your post saying it is only good for paper! ;-)

Ifeel sure it will be OK because the instrument only has nylong
strings. I did a drednought bridge with white wood glue and it has
been fine for two years now. I'm intder the very strong impression
that the white glue is a lot stronger than the spruce top the bridge
is stuck to, so I guess it will suffice.

Regards hide glue, I don;t have great confidence in it, because that
was what the bridge was originally stuck on with and it had pulled
off! What's more, it was the glue that pulled apart - not the wood.
And... both mating surfaces had been scored to maximise ashesion. It
was my first encounter with hide glue. It led me to belive that the
stuff was not as strong as the wood it was joining. It's only a form
of gelatine, I understand... I may be wrong about that; the bridge
might have come unstuck due to heat or damp or something, and the fact
that the instrument had been strung with steel strings. Perhaps it was
inferior hide glue.

Anyway, thats to everyone for the input on that one.

Jim T

[Cyberserf]

Post by Jim T
Regards hide glue, I don;t have great confidence in it, because that
was what the bridge was originally stuck on with and it had pulled
off! What's more, it was the glue that pulled apart - not the wood.
And... both mating surfaces had been scored to maximise ashesion. It
was my first encounter with hide glue. It led me to belive that the
stuff was not as strong as the wood it was joining. It's only a form
of gelatine, I understand... I may be wrong about that; the bridge
might have come unstuck due to heat or damp or something, and the fact
that the instrument had been strung with steel strings. Perhaps it was
inferior hide glue.
Anyway, thats to everyone for the input on that one.
Jim T

Jim,

Glad it worked out, but seriously, hide glue is the sh*t. You need two very
well mated and unscored surfaces...it is not a good gap filler, but it dries
in a particular fashion. The glue forms a molecular bond that is self
clamping (it gets tigher as the moisture leaves the glue). Do some googles
on the stuff (or drop me a line and I'll send you some links). If it fell
apart then either 1) the glue was badly prepared or 2) the joint was moved
after it had gelled or 3) it was exposed to high heat/humidity. It will
dissasemble very well under those influences. It is indeed a gelatin and it
is mega strong with very little creep...it crystalized and pulls everything
towards it (I install interior cleats with my fingers, over time, the cleat
clamps itself to the top)...very strong. However, if you disturb the joint
after the glue has gelled (cooled), but before it has set, the molecules
will all be broken and the joint will be weakened. In my opinion, Hide glue
is extremelly strong and as a traditional luthiers glue, well worth getting
to know. It does take some getting used to and needs to be properly handled,
but it is kick ass at what it does. I wasn't kidding about those thousand
year joints in egyptian museum furniture still holding strong with Hide
glue.

White glue is simply not a good glue for any woodworking (unless it is a
quality PVA like Lee Valleys 2000G). Next time, go with some yellow PVA (aka
Aliphatic Resin)...much better...but still, IMHO, not as good as Hide Glue
;-)

Cheers, CS