Microscope sample mounting resin

Tobit Curteis <tc [at] tcassociates__co__uk> writes

>I have been using a clear 2 part acrylic resin supplied by Trianti,
>for mounting paint cross sections, for many years. The material is
>extremely good, but has a relatively short shelf life. As I work
>with only a limited number of samples, the resin tends to set in the
>can and I end up throwing large amounts each time.
>
>Has anyone come across a clear mounting resin that has a long shelf
>life or is supplied in small sealed containers that can be opened
>one at a time (rather than all in one go as is the case with a 1kg
>can). If so names of UK suppliers/ importer would be very useful. In
>addition has anyone had any experience with a 2 part methyl
>methacrylate resin called Tensol 70?

I assume Tobit Curteis is referring to the 2-part polyester (rather
than acrylic) resin supplied by Alec Tiranti, which I know is widely
used in the UK. It does serve a lot of needs for embedding
cross-sections, but there are instances when it is not appropriate.
The formulation was changed a couple of years ago to one that gives
a much harder cure; this is not good for softer material and tends
to lead to 'scooping out' of the paint fragment during grinding. In
my experience the resin lasts perhaps 6 months in an open tin in the
cupboard; you can keep it chilled but will need a special
refrigerator to do this, so it is probably worth accepting the
relatively short life in return for the comparatively low price and
ready availability.

Tensol 70 is the resin used for 'EasySections' supplied by VW Fecit
<info [at] easysections__com>. It is quoted as having a lifetime of
"greater than one year" and comes in smaller quantities. I use it
from time-to-time, but find that it has a significant amount of
shrinkage during curing. It is also much softer than the Tiranti
resin, for which it preferable.

There are a number of other products available on the UK market that
are appropriate for preparing cross-sections, such as epoxy resins
(for example we recently used a product called EpoThin for mounting
dry pigment samples for EDX analysis) and light-curing acrylates
(Technovit 2000 LC from Heraeus Kulzer, Germany; this requires an
intense blue light source to trigger hardening). Each has pros and
cons and may still not fit your shelf-life criterion. You should,
however, probably consider making the decision of which is the most
appropriate resin for your work on other bases than shelf-life.
Factors such as if it affects (dissolves) material in your sample,
low viscosity, has the correct cured hardness, does not exhibit
fluorescence, has a long cured shelf life and so forth are far more
important.

Dr. Nicholas Eastaugh
5 Whitehorse Mews
Westminster Bridge Road
London SE1 7QD UK
+44 20 7928 8385


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                  Conservation DistList Instance 17:32
                  Distributed: Monday, October 6, 2003
                       Message Id: cdl-17-32-004
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