Unibond 800

[Ron Nossaman]

If any of you are using Unibond 800 in the shop, I have a question.

I usually turn out the lights on wet glue, so everything is dried and
stable by morning and I'm not working around clamped assemblies all day
in my pocket shop, but today, I glued up some stuff early in the day.
Checking the consistency of the glue a while ago, I judged it solid
enough to take out of the clamps and trim up for assembly tomorrow.

Trimming the squeeze out, the stench was overpowering, and I gave up
that idea pretty quickly. I've done this with the old formulation, but
the recent formula change has made a much nastier stuff, at least before
it's fully cured. It hasn't been a problem with previous projects and
this same batch, but I haven't tried to trim it early until now.

So the question: Is my nose hallucinating (as it does now and then), or
has anyone else run into this? The pitch is that the new mix contains
10% the formaldehyde the original version had, and should smell less bad
as a result. So far - no.

It's still pretty first rate stuff, and by tomorrow, it may quit
stinking altogether (I hope), but for now, WOW!

Ron N

[Douglas Gregg]

Ron,
Formaldehyde will degrade with the fixing process. It reacts quickly
with amino acids in proteins esp. with lysine. If there is less amino
acid to react with, it will last longer and outgas longer. The
formulation of the glue or the type of wood glued will affect the
speed of the reaction. Less amono acid, more smell.

Doug Gregg

[Douglas Gregg]

Ron,
After thinking about this a little more, I came up with this thought.
Hide glue is a very concentrated source of relatively pure collagen
protein (from hides) that is very high in lysine. Formaldehyde would
quickly fix hide glue and the hide glue would be inactivated as an
adhesive through the cross-linking of the lysine (that is needed for
the glue strength). Also, the rapid inactivation of the formaldehyde
would reduce the available formaldehyde to react with urea or whatever
there is in Unibond 800. For both reasons, that would make Unibond 800
a poor choice for surfaces that are being re-glued after having had
hide glue on them. A water based glue such as titebond would more
likely re-activate the hide glue and bond with it. Of course, more
hide glue would re-active it too.

Can you correlate the formaldehyde smell with use on new wood, or with
previously glued wood? My guess is that new wood would outgas more
formaldehyde since there is not much protein present in new wood to
inactivate the formaldehyde in the Unibond 800 glue other than what is
included in the Unibond formula. I am curious if this was the case.

I worked a great deal with formaldehyde fixation of tissues in my
pathology career, so this is not new to me. Failure of tissue fixation
is usually due to an excess of protein (ie tissue) in the
formaldehyde. We tried to keep the amount of tissue down to about 10%
of the volume of formaldehyde fixative.

Doug Gregg

[Terry Farrell]

Hi Ron - As you know, I use Unibond 800 for most all my laminating. I think the last gallon I bought was the first one of the updated formulation - I made several slabs of ribs with it. Unfortunately though, each time I made it I do as you usually do - glue 'em up in the evening and let it cure overnight - plus I vacuum bag them, so even if it did get stinky, I don't think I'd get much of it anyway.

I'll have my warning flags up though next time I laminate up a bridge or cut-off, as I clamp those into position - especially if I have some reason to take it out of clamps early. They say that you can safely take clamps off when it gets rubbery. I really feel so much better if I wait until it gets hard - perhaps to no true advantage other than sleeping better.

As a side note, have you tried the whitener they have available now for Unibond 800? As I'm sure you are aware, the untinted "light" colored Unibond 800 is kind of a medium-dark brown - much darker than spruce. If you max out the permissible amount of whitener in it, it gets almost as light as titebond. You still don't get quite as invisible a glue joint as Titebond, but it comes fairly close. I like it.

I thought you were using Titebond for all your laminating - no?

Will I see you in Atlanta? Loui (sp?)? My wife was almost able to go, but can't because she has a class to attend that conflicts. My wife and yours would have fun together - they could hit all the resale shops in the area - in many other ways, except for the fossil and rock hunting interests, they seem like two birds of a feather (and lovely ones at that)! ;-)

Terry Farrell

[Ron Nossaman]

On 7/7/2014 12:29 PM, Terry Farrell wrote:
>
> I'll have my warning flags up though next time I laminate up a bridge
> or cut-off, as I clamp those into position - especially if I have
> some reason to take it out of clamps early. They say that you can
> safely take clamps off when it gets rubbery. I really feel so much
> better if I wait until it gets hard - perhaps to no true advantage
> other than sleeping better.

If the assembly is stressed, as with laminated curved ribs or cutoff
bars, absolutely. I might take the clamps off temporarily after the glue
firms up to trim excess squeeze out so the glue that actually belongs
there will dry more completely overnight (Titebond), but it goes right
back on the caul until it's more thoroughly cured to eliminate spring
back. So it is to a real and true advantage if the dependability of the
laminated curve is of interest to you. With Titebond, I leave rib stock
in the cauls for maybe three days. With Unibond, overnight would be
plenty as it doesn't have all that moisture to get rid of before it's
stable.

> As a side note, have you tried the whitener they have available now
> for Unibond 800? As I'm sure you are aware, the untinted "light"
> colored Unibond 800 is kind of a medium-dark brown - much darker than
> spruce. If you max out the permissible amount of whitener in it, it
> gets almost as light as titebond. You still don't get quite as
> invisible a glue joint as Titebond, but it comes fairly close. I like
> it.

I haven't tried it. The new formulation looks darker to me than the
original, so I may end up trying it yet.

> I thought you were using Titebond for all your laminating - no?

Generally, yes. I typically use Unibond 800 just for assembling my
pinblocks. It works as well as epoxy, at considerably less cost and is
easier to clean up. The last bridge capping I made up, I used Unibond
800, and it seemed to work as well as epoxy there too, again at
considerably less cost. Since my notcher cuts to a depth of slightly
over the thickness of the capping material, I back the capping with
about 4mm of hard maple so the cut doesn't go into the root. Although it
might make an interesting looking bridge, I prefer having the structure
of full coverage.

> Will I see you in Atlanta? Loui (sp?)?

Nope, unfortunately. I suspect Loui wouldn't mind too much being forced
into a Thrift store or 12 with a partner in crime, but it's not in the
cards this deal.
Ron N

[Will Truitt]

I've been using Unibond 800 to glue up my bridge cap laminations also. I have also used it to glue up hybrid pinblocks. It's cheaper than the epoxy and maybe a little less hassle to use. I have a gallon that is almost empty. It's close to 2 years old, and I have kept it refrigerated the whole time when not out to be warmed up to be used. It doesn't stink, and the just in case test glue ups seemed fine a month ago when I glued up a laminae, as has proven the finished cap. It is lighter than the epoxy, and the glue lines are thin and near invisible from the side. It looks like a straight grain in the notch.

It is my habit to let the piece stay clamped overnight.

Will Truitt

I'll be ordering some more shortly. When did the new formulation come out?

[Ron Nossaman]

On 7/7/2014 2:46 PM, Will Truitt wrote:
>
>
> I'll be ordering some more shortly. When did the new formulation come out?

I'm not sure exactly. First of the year or thereabouts.

Throw away your left over catalyst, incidentally. It won't work with the
new mix.

Ron N

[Will Truitt]

Thanks for the heads up.

-----Original Message-----
From: pian...@googlegroups.com [mailto:pian...@googlegroups.com] On Behalf Of Ron Nossaman
Sent: Monday, July 07, 2014 4:09 PM
To: pian...@googlegroups.com
Subject: Re: [pianotech] Unibond 800

[Terry Farrell]

Could that be the cause of that new 1/4-sawn pinblock I made up tuning like the tuning pin is planted in a hard rubber ball?    Boing!

;-)

Terry Farrell

[Ron Nossaman]

On 7/7/2014 4:36 PM, Terry Farrell wrote:
> Could that be the cause of that new 1/4-sawn pinblock I made up
> tuning like the tuning pin is planted in a hard rubber ball?
> Boing! ;-)

No, but that's exactly why you shouldn't be tinting your glues in bright
colors and storing them in Play-Doh cans.

Splatt ._.
Ron N

[Terry Farrell]

You got some sort of sick twisted perverse problem with Play-Doh? Well, except that the lids just don't seal all that well?

Terry Farrell

[Will Truitt]

I tripped over this posting this morning about troubles with the new Unibond 800 formulation for someone. I'll just pass this on. http://www.woodweb.com/cgi-bin/forums/veneer.pl?read=730808

FWIW, great or small.

Will

-----Original Message-----
From: pian...@googlegroups.com [mailto:pian...@googlegroups.com] On Behalf Of Ron Nossaman
Sent: Monday, July 07, 2014 3:09 PM
To: pian...@googlegroups.com
Subject: Re: [pianotech] Unibond 800