Re: [BKARTS] reversible, archival glues

[Talas <info@xxxxxxxxxxxxxxx>]

This is both an interesting and endless discussion.  People always ask me,
should I buffer my wheat paste with calcium carbonate?  And my feeling is
no, which always takes us on an endless discussion as to why, since we
(Talas) openly state that it is acidic in its natural form.

The testing of pH on modern materials has been both a very useful and also a
difficult thing to manage.  The words archival, acid free, etc are used
quite recklessly these days, with few people really understanding what they
mean.  In theory having something that is pH neutral is beneficial, but this
is easily achieved through modification with chemicals, but would you rather
have a lesser quality base material modified to be pH neutral (acid-free);
or something that may not be pH neutral (acid-free) but made of a material
known to have great long term stability?

Just looking at the numbers, the first choice may seem better, but is it
really?  A good example of this is the Davey Acid Free Binders Board.  Here
you have a board that is technically pH neutral, but it is made from almost
100% recycled material, with lignin content commonly between 70-90%.  It's
acid free, but can you really consider it a product suitable for long term,
conservation quality work?  I would say not.  The same is true with most of
your common office paper now labeled as acid free, and so forth.

Getting back to the wheat paste, this is a product that has been in use for
certainly hundreds of years, and we understand through our own eyes how it
behaves over time.  Yes it's pH in a dissolved state is acidic, but it has
shown to be very stable, reversible, and effective from its history.  Is it
better to add a buffering agent to increase the pH?  Depends on who you ask,
many would say yes, but I would think most would say no.  Why disrupt the
natural balance of the product with an internal "struggle" if you will,
pushing the pH from its natural resting state.

I haven't even touched upon the PVA's, and not sure what else needs to be
said.  There are certainly MANY manufacturers out there of these adhesives,
and it is unfair to say that manufacturers don't care - they do about the
industry they serve - which is most of the time not ours.  The Jade 403 was
developed for the food packaging industry, but was uncovered by some
conservators many years ago who found it to be very favorable for their
needs as well.  However changes in this product have been dictated many
times by the FDA and out of the hands of the actual manufacturer.  So its
not as always clear as it seems who makes the decisions as to product
changes.

So to step down from my soap box I will say, just be careful, and do what
feels right.  Do as much research as possible, and share experiences both
with your peers as well as with your suppliers. 

Regards,
Aaron Salik
 
Talas
20 West 20th Street
New York, NY 10011
212-219-0770 Phone
212-219-0735 Fax
http://talasonline.com

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