Regalrez

Ewa Bjordell <ewa [at] konservering__se> writes

>We have heard of the hydrocarbon resin Regalrez which theoretically
>appears to suit our purposes. Regalrez, however, has so far very
>limited use in Sweden. Therefore we would be very grateful for any
>advice from colleagues with experience from working with Regalrez.

Regalrez worked very well as a protective coating but with the
addition of  "Cosmolloid 80H" (a blend of microcrystalline waxes,
added in proportion of 10% to 20% of the dry resin weight).
Cosmolloid helps reduce the high gloss of Regalrez. It also makes it
less brittle.

Note that in this example the original surfaces were mat, but not
lean, and their texture was very smooth (the plaster underneath the
paint layer was not sandy or "grainy"). Regalrez-Cosmolloid did not
noticeably change the appearance, the colour or the surface finish.
It may be less advisable on a very lean surface, which may tend to
irreversibly absorb the medium and change its appearance and optical
properties.

I found that the method of application made a big difference. In
this case, we wiped the surface with an absorbent soft cloth after
brushing on the varnish, to even-out and remove the excess before it
dried. We wanted to avoid creating a thick impermeable layer, so it
worked well this way and was just enough to protect original
water-sensitive finishes or watercolor retouchings.

I was concerned with the possibility of future dust adhering to the
surface (due to the presence of wax in the mixture) but the surface
after drying did not feel tacky to the touch. The drying time was
quite slow however (Stoddard being used for the solvent).  This
layer was easily removable after drying. Some conservators prefer
adding Tinuvin to Regalrez because, although it is believed to be
stable,  its natural long-term ageing properties are not really
known yet.

Would "Soluvar" be a possible alternative ? (a "Liquitex" brand
acrylic varnish which is said to be stable and soluble in low-polar
solvents)  ?...   I have not used it myself, but it may be worth a
try. It is sold ready-mixed, in either mat or glossy form, and
already contains a stabilizer.

Anne Lapointe
Easel Painting / Wall painting conservator
CAPC-ACRP Member (Paintings and Architectural finishes)
Montreal, Quebec, Canada


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                  Conservation DistList Instance 18:40
                 Distributed: Monday, February 28, 2005
                       Message Id: cdl-18-40-004
                                  ***