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Subject: Flooring


From: Ramona Duncan-Huse <rduncan>
Date: Thursday, August 27, 1998
Just some comments to confirm the info passed along on vinyl tile.
We recently performed Modified Oddy tests as specified in an article
written by GCI in  Studies in Conservation.  We tested Marmoleum
Dual made by Forbo Industries out of Hazelton, PA..  It is a vinyl
composition tile made from linseed oil, cork and 'rosins' mixed and
calendared onto a jute backing.  On day 2 of the test period the
copper and lead foils started to dull on the abraded side,
progressing slowly to a slight tarnish by day 10 through day 28.
Under 40X magnification both the abraded and polished sides of the
copper foil showed tiny areas of green corrosion, with some slight
discoloration to the silver test coupon at the end of the 28 day
test period.  We evaluated this reaction  to be consistent with a
temporary use rating as described by GCI; meaning for our purposes
it would not be used as flooring in our storage vault but could be
used in areas where collections temporarily reside: exhibit prep and
conservation lab areas.  We are waiting for a sample of the adhesive
to test, but the application will be in a new building as opposed to
renovation of an area where collections already reside and would be
affected by initial outgassing.

We tested Johnsonite vinyl 1/8" wall base made by Jonsonite Inc. out
of Chagrin Falls, OH.  It is a solid vinyl product, though flexible.
Their was no initial reaction to the vinyl product; after 28 days
the copper and lead foils each exhibited slight tarnish on the
abraded sides.  Under 40X magnification, the tarnish was identified
on the copper foil as barely visible green corrosion overall.  The
lead sample contained small, isolated green corrosion on the abraded
side, while the polished side exhibited a faint white tint overall.
We evaluated these reactions to be consistent with GCI's permanent
use rating - because the reaction was slight - and again the base
was not going to be used in our storage vault, but in labs and
offices.  We are waiting for an adhesive sample to test.

It might be significant to observe that for most of our tests, the
only place where tarnish was found was on  the abraded side of the
foils.  This might indicate that the oxidized surface of the foils,
however slight, prohibits corrosion to some extent.  It might be
similar with the oxidized surfaces of materials in our collections.

I know products change a great deal and performing the Oddy tests
can be time consuming- so hard data is difficult to come by.  It
would be great however, if there could be a register of sorts for
those products that have been tested by individual labs so people
who need recommendations fast (that's how it usually goes) can look
at a single source to see what products are being recommended for
specific applications.

By the way, we tested a new medium density fiberboard product called
Wheatboard out of Wahpeton ND  that is advertised as having low
formaldehyde emissions - made from wheatstraw and a 'non-toxic'
polymeric diphenylmethane diisocyanate MDI emission-free binding
agent.  After 3 days in the test chamber we had a dense black
tarnish on the polished and abraded sides of the copper and lead
coupons. The silver coupon did not show any reaction at all.  For
our purposes, we evaluated this reaction to be consistent with an
unsuitable rating identified by GCI .  We are using sealed and
laminated Medite II.  I have other products that we have tested if
people need information.

Ramona Duncan
Head of Conservation
Indiana Historical Society

                  Conservation DistList Instance 12:21
                 Distributed: Thursday, August 27, 1998
                       Message Id: cdl-12-21-002
Received on Thursday, 27 August, 1998

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