[CAUT] glues, Poletti

[Porritt, David]

Diane:

 

I'm really sold on the Titebond Trim and Molding Wood glue.  It fills
gaps, doesn't run and I've had no problem with loose hammer heads.  The
doesn't run or drip thing is a real plus for me.

 

dave

 

David M. Porritt, RPT

dporritt at smu.edu

 

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Diane Hofstetter
Sent: Thursday, November 29, 2007 2:10 AM
To: College and University Technicians
Subject: Re: [CAUT] glues, Poletti

 

I'm interested in the question of glues, because I recently watched an
unsighted technician gluing grand hammers on with Titebond.  Most of his
glue joints were starved for glue and none had glue collars.  I always
used hot  hide glue, which I found easy to use, made great glue collars
and gave a nice, straight job.  But I can see where that is impractical
for this tech, so have been wondering what I might suggest to him in the
way of a better glue and better method. Ted, you mentioned fish glue for
key bushings, do you think it would be appropriate for hammers?  Does
anyone have any good ideas?
Thanks!
Diane

Diane Hofstetter

> From: edward.sambell at sympatico.ca
> To: caut at ptg.org
> Date: Wed, 28 Nov 2007 15:15:06 -0500
> Subject: Re: [CAUT] glues, Poletti
> 
> I read somewhere that all glues will creep to a greater or lesser
degree. 
> When I was teaching at George Brown College, it was impractical to
have a 
> large number of glue pots for hammer gluing, much as I would have
preferred 
> hide glue, so we used Titebond. It was much harder to extract hammers
from 
> the shanks with this than those glued with hide glue, though ten
minutes 
> with a heat gun let them be pulled off readily.The soundboard splits
we 
> commonly encounter in old pianos are mostly not true splits at all,
but are 
> separated joins, thus showing that creep has occured by shearing at
the 
> ribs. It can be assumed that most of these soundbards were glued with
hide 
> glue. It is just as well. as if the joints hold, there would be true
splits, 
> which would be very difficult to shim unless the grain is very
straight. I 
> enjoy working with hide glue, but it is more demanding. It must be
carefully 
> controlled in viscosity, though this is also an asset; large work such
as 
> cabinetry (and soundboards) should be heated, clamps prepared ahead of

> assembly and applied very quickly.I have taken to using fish glue for
key 
> re-bushing;, but found it necessary to prime coat the mortices first
with a 
> 50-50% dilute with water. It is slow setting, but will take hold
quickly. 
> Fish glue is easily reversible with the usual mix of warm water and a
little 
> wallpaper remover. It is availabele from Veritas. There is a small
bottle 
> with a brush in the lid which is ideal for light field repairs, and
refill 
> 17oz. bottles. I have seen failures with hide glue through lack of 
> understanding. One new grand I saw had a large number of loose
hammerheads. 
> The glue collars were all near black, indicating the glue had been
boiled. 
> Hide glue must not be heated above 150F. 140F to 145F is considered
the 
> proper range. Bill Spurlock recommends the use of a Rival Express Hot
Pot 
> and setting its temperature with the aid of a candy thermometer. I saw
these 
> recently in Wal-Mart, and think it a great idea. They cost around $15 
> compared to $100 or so for a dedicated glue pot.
> 
> Ted Sambell
> ----- Original Message ----- 
> From: "Richard Brekne" <ricb at pianostemmer.no>
> To: <pianotech at ptg.org>; <caut at ptg.org>
> Sent: Wednesday, November 28, 2007 2:40 AM
> Subject: [CAUT] glues, Poletti
> 
> 
> > Hi Anne
> >
> > Creep in conditions like you mention seem quite easy to understand.
There 
> > is a kind of shear stress on a hitch pin rail that is glued to a 
> > soundboard. But there is another point from his site I found very 
> > disturbing . The assertion that Titebond and similar glues never
really 
> > harden and impart (to some degree) kind of damping effect, absorbing
some 
> > of the vibration energy instead of either reflecting or
transmitting. This 
> > has immediate implications for modern piano building as well as
older 
> > instruments. I'm not so sure how much a problem Creep is in
situations 
> > where there is not immediate and significant levels of shear stress
on the 
> > glue. But I'd like very much to hear more in depth comments about
all this 
> > in general.
> >
> > I'm not sure I'd have a problem using Titebond to fix a broken shank
out 
> > on some field repair job. But thats not really what I was talking
about. 
> > When in a restoration shop one has a variety of choices at hand.
> >
> > Cheers
> > RicB
> >
> >
> > Ric wrote:
> >
> > Hi Folks
> >
> > Reading in one of Anne Ackers i found a reference to the website
> > of one
> > Paul Poletti who has a side dedicated to glue. Please look over the
> > following and provide comment.
> >
> > Thanks
> > RicB
> > ******************************
> >
> >
> >
> > He's absolutely right. Most harpsichords built with aliphatic glues
in 
> > the 1970's and 1980's demonstrate cold creep very nicely with the 
> > shrinking of the gap as the soundboard creeps forward, e.g.
> >
> > Besides, hide glue is so EASY to use. If it stinks, you're using bad

> > stuff.
> >
> > Anne 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/caut.php/attachments/20071129/1ee0e1e9/attachment.html