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Polyvinyl Alcohol with glycerol by Howard Webb (St. Louis, MO, USA) |
The following are some personal
comments on PVA-G. Walter Dioni has provided a good formula, but
there were a few surprises when I attempted to follow his
instructions. A bit of a "warning" may help others. I like
using this mountant, and would encourage others to try it.
My standard mountant has been jellied glycerine, but after the nice articles by Walter Dioni, I decided to try his polyvinyl alcohol and glycerol.
The supplies were all locally
available for only a few dollars. O'Glue was readily available at my favorite art supply
store. A small tube will make about four batches. Borax was
a bit harder to find, not being at my usual grocery or hardware
stores. It did however turn up as 20 Mule Team Boraxo at
Wal-Mart, though a box is definitely over-kill for the amount
needed. It took asking several pharmacies to find a small bottle
of glycerine.
The quantity of ingredients specified in the formula all fit
nicely into an empty plastic film canister, so I measured out some
water and marked "fill lines" for the various ingredients.
What Walter failed to mention is that
polyvinyl alcohol and borax are standard ingredients with another
purpose - "slime" (try a web search for "polyvinyl alcohol
borax"). And the amount of borax will change the consistency from
runny to almost solid rubber (before adding glycerine).
When I first tried mixing the
mountant, and added a saturated borax solution to the polyvinyl
alcohol, the contents turned into a solid block of rubber. I
thought I must have made a mistake (and started another batch).
For the second batch I mixed the polyvinyl alcohol and glycerol.
It lumped, then frothed when I shook it. I thought this must also
be a mistake. I then poured glycerol over the first mixture (the
rubber block), and tried chopping it in. In near despair, I set
both aside
in a warm place (on top of a flourescent light ballast), and left them
for the night. The next day, when I checked them, they had both
turned into the desired, clear thick syrup.
When I go to make another batch (years
from now with my current supply), I would add the PVA, glycerine and
borax (in that order) to a container, then shake them all together,
then gently warm it to remove any bubbles.
For a good article on the technical chemistry of polyvinyl alcohol and borax, check out:
http://www.ccmr.cornell.edu/education/modules/documents/ScienceofSlime_student.pdf.
Comments
to the
author Howard
Webb are welcomed.
Published in the November 2004 edition of Micscape Magazine.
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