On Wed, 16 Nov 1994, Allison Smith wrote:
 
> Hello all, remember that Whiteout discussion way way back?  What was the
> concensus on B-72?  Is it better to use than Nailpolish?  If so, what was the
> agreed best solvent to mix it in?  Acetone?
> By the way, I have all the whiteout messages from the archives, actually, I've
> been indexing the whole lot as part of a class project.  I was under the
> impression that using B-72 (without the whiteout) was the best  marking method
 .
> However, I wasn't sure about solutions, so emailed Carolyn Brady (remember the
> Victorian house museum with all the whiteout all over, I swear I know the whol
 e
> story by heart.,) Anyway, Carolyn is sticking to marking her objects with
> Nailpolish, being under the impression B-72 was too risky to use because of th
 e
> solvent factor.  Whats the deal, um, I mean the professional concensus out
> there?  I really need some professional opinions, since my registrar friend
> wants me to do a marking demonstration, and I want to do whats best for the
> objects.  Reply to me or to the list thank you thank you thank you!
> Allison
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ~~
>                                 Allison Smith
>                         University of Wisconsin Madison
>                    School of Library and Information Studies
>                             [log in to unmask]
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>
I'll try to clear this up.  Whiteout, nail polish, and Acryloid B-72 are
all something dissolved in a solvent.  I'll just skip whiteout because
that's been done to death.  However, nail polish is some polymer (and
some coloring agent if it's not clear) dissolved in a solvent.  The ones
I used to use smelled like they contained acetone and amyl acetate
(though lots of things might be used).  When the solvent evaporates you
are left with a "skin" of solid polymer (polymer being some plastic).
The problem with nail polish when compared with Acryloid B-72 is not the
solvent (which could be just the same thing) it is that the plastic that
are used are often not very stable.  They "dry out", peel, yellow, crack,
and after awhile you can lose you number.  Depending on your
environmental variables, after awhile could be one year and 30 years.
The reason conservators recommend Acryloid B-72 is because it has been
tested in the past and is known to be very stable compared to many
alternatives.  The phrase is "up to a hundred years in a museum
environment".  It's the best we know about.  You can buy Acryloid B-72
already dissolved in toluene, but toluene is a fairly toxic substance and
a suspected carcinogen.  Therefore, I recommend that people buy solid
beads and dissolve some in acetone (about a 10% solution) because acetone
is less toxic.  You can even buy small bottles with brushes so it can be
applied just like nail polish.  I think I gave some references during the
whiteout controversy before, that discussed how to mix it up.  If not,
I'll be glad to put them on the list.  I hope this clears up the
questions.
 
Jessie Johnson
Materials Conservation Lab
Texas Memorial Museum
University of Texas at Austin
PRC #122, 10100 Burnet Road
Austin, TX  78758
(512)471-6090