Exhibit cases

It recently came to my attention that additional exhibition cases
were being constructed for Special Collections based on the 20
year old cases they already had.  Because I was not involved in
this project until the cases were almost complete, I have had
little imput in the design, and choice of wood, but have obtained
potentially useful information for one starting from scratch.  I
offer what I know, and encourage others to contribute whatever
they may to this very confusing, complicated, and little
explained (in practical terms) issue.

Harold Berndt, University of California, Forest Products Lab,
1301 S. 46th Street, Richmond California 94804  (415) 231-9488
welcomes questions and is VERY interested in the influenuce of
various gases on artifacts. He has just submitted an article to
the AIC journal and is interested in knowing whether or not
conservators would be interested in this type of research.
(Thanks to Robert Espinosa for giving me Dr. Berndt's name). He
talked about the difficulties in tracking deterioration in
cellulose (metals are easier because they change weight, and
something visual also occurs to the material being tested).  He
hypothesizes that conservators should be able to test their
exhibit cases in-house (by using some type of lead strip, and
track its weight).

Dr. Berndt alerted me to textile materials (for lining the case)
that might be treated.  If, for instance, it is 100% cotton, but
is wrinkle resistant, or flame resistant, it has been TREATED,
likely with something undesirable from a conservation point of
view (formaldehyde).  He recommends washing such fabrics if they
are selected.  If these materials hydrolyze, formic acid will
result.

Dr. Berndt is interested in CARASORB (also recommended by Robert
Espinosa) sold by Conservation Materials in Nevada.  Carasorb are
air cleaning pellets (potassium permaganate coated) and will
absorb the nasty materials in your case.  It starts out purple
and turns brown so it can be used as an indicator of how quickly
products in your cases may be outgassing.

Because most testing has been done for metals rather than organic
materials, it is hard to know exactly what should be done for
exhibiting books and papers.  The main concern of outgassing (for
scientists, at least) is with metals (bronze, zinc, and lead).  A
constant RH under 70% (!) and constant temperature should
eliminate some concern (according to Dr. Berndt).  As far as
choice of sealant, he feels that it might be better NOT to seal
(see below) as long as the case is kept dry.

I spoke with Bill Minter about a source for pure, stable textile
materials. Bill recommended Thomas Klaas at Test Fabrics, Inc.
(201) 469-6446 in Middlesex, New Jersey 08846 (P.O. Box 420, 200
Blackford Avenue).  Mr. Klaas is willing to send you sample
materials, and try to work with you in obtaining what you want.
He works with the dye house so that he can get you a specific
color that does not have resins, or finishes and has been water
rinsed. He goes after fabrics that have direct dyes which he
describes as "fairly benign."

I also spoke with Bonnie Jo Cullison (Newberry) about her
experience with exhibition cases.  They went with an interior
plastic laminate on the interior of their cases, but she doesn
not know how good or bad this is. (it was something the British
Standards Group was investigating at the time). The cases still
smell, which makes her suspicious.  She recommended that I speak
with Carol Turchin at the Chicago Historical Society because they
lined their cases with aluminum foil. (I have not pursued this
lead, but the number there iw (312) 642-4600 if someone wants to
check this out). Bonnie Jo said that ideally you would want a
mica-filled or metal flake paint, (Tim Padfield) but she couldn't
locate this.

Eleanore Stewart recommended I speak to William Ginell at the
Getty. Dr. Ginell told me that walnut was a poor choice for an
exhibition case. Walnut, and other hardwoods, like oak (which is
the worst) give off organic acids, and they are especially bad if
kiln dried.  Softwoods like spruce and pine are better.  He feels
the woods SHOULD be sealed, and the best sealants are polyester
or epoxy.  The worst sealants areq PVC paints, oil based paints,
urethanes.  Always use a water based sealant rather than oil
based.  Avoid alkids, urethanes.

Staining in general may not do harm.  Alcohol based stains are
ok, but make sure they dry thoroughly.  Avoid oil based stains.

Allow a case to dry thoroughly, open, with good air circulation.
This may take a matter of weeks.

He feels the worst situation is the use of a urethane because it
is KNOWN to give off formaldehyde.

Other materials to be cautious of: wool, it has sulfur, and you
will get corrosion with silver objects.  Also possibility of
forming SO2. You want to be sure the dye is free from sulfur.
silk, is not stable in light.

Good textile materials: cotton, linen (bleached and double
boiled).

Sorry this is so fragmented, but I wanted to get it out for
comments, before I lost the energy for it.  All comments are
welcomed and appreciated... Hilary

                                  ***
                  Conservation DistList Instance 2:15
                  Distributed: Saturday, April 1, 1989
                        Message Id: cdl-2-15-003
                                  ***