Butcher's wax

Seoyoung Kim <seoyoung.kim [at] cls__glasgow__gov__uk> writes

>Has anyone experienced any problems with using Butcher's wax (also
>known as bowling alley wax), such as difficulty in removing,
>changing appearance over time etc? ...

I have used Butchers wax (carnauba wax, mostly) for years and have
always been happy with it.  I still keep Renaissance wax
(microcrystalline wax) available, but for putting a wax coating on
something, I prefer carnauba.  This is because in my experience, if
microcrystalline gets into a small crack, such as in craquelure, it
can dry white, and needs to be removed with something toxic such as
xylenes or toluene.  carnauba wax can do this also, but it seems to
do it to a lesser extent, and when it does, the lines are not as
white.  I think carnauba dissolves slowly in non-polar solvents, but
I fear that sometimes you might need to use solvents such as xylenes
or toluene to remove it, but this is little different than
microcrystalline.  I usually use microcrystalline wax to lubricate
mechanical metal fasteners, where visibility is less of a concern,
and where the longevity of microcrystalline wax may be superior.

One minor problem I have seen with carnauba wax is that it can cause
swelling to certain types of plastic, specifically polyethylene,
which I have seen warp when exposed to wax solvent vapors.   I have
seen this happen to sheets of clear polyethylene used in photo and
slide pages, and I have also seen it happen to Volara and Plastizote
foam.  As I understand, these plastics are considered by chemists to
be essentially a very had, insoluble waxes, so that would explain
why they might swell when exposed to wax solvents.  It is
reversible, and after a few days of fresh air, the warping of the
plastic will go down.  Regardless, I'm sure the solvents in
microcrystalline wax are similar and would probably have the same
effect on polyethylene.

Thomas J. Braun
Daniels Object Conservation Laboratory
Minnesota Historical Society


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                  Conservation DistList Instance 18:56
                  Distributed: Saturday, June 4, 2005
                       Message Id: cdl-18-56-006
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