Microballoon mixture for wood

Recent discussion on the DistList regarding Araldite 1253 bulked
epoxy filler material addresses in part the issues of its
removability from wooden objects at a future date. For thick fills,
I apply a substantial barrier coat of hide glue on all wood surfaces
to be filled. When this is dry, I sometimes apply over this a length
of fine-gauge electrical resistance wire and tack it down in a
meandering-line pattern with drops of glue. The Araldite epoxy
filler is then applied over this, embedding the wire in the epoxy,
but allowing the two ends of the wire to project out beyond the
Araldite.

To remove the hardened Araldite with ease, apply a low voltage, low
amperage electrical current to the wires, completing a circuit and
generating low heat. I use an adjustable rectifier normally used for
electroplating. The electrical current causes the wire to heat up
gradually, which will slowly soften both the hide glue and the
epoxy, allowing it to be easily tooled out of the fill cavity. Some
experimentation is required to get the right diameter and resistance
of wire, the correct amperage and voltage for that specific
resistance wire, and the length of time current is applied.
Different thicknesses of fills require different times of current
application to soften the entire fill.

This will only work if a detailed treatment report accompanies the
object so that a future conservator or restorer understands the
function of the wires. And it is only appropriate if the projecting
wires are not visible on a primary surface. In recent experiments
in our studio, I have found Araldite to be easily removable as long
as 5 years after original application.

Robert Mussey, Furniture Conservator
Robert Mussey Associates
1415 Hyde Park Avenue, Suite 302
Boston, MA 02136-2648
617-364-4054
Fax: 617-361-4105


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                  Conservation DistList Instance 19:48
                  Distributed: Friday, March 31, 2006
                       Message Id: cdl-19-48-004
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