Microclimate frames

David Frank Bugeja <david-frank.bugeja [at] gov__mt> writes

>There is considerable literature on microclimate frames, where the
>majority of the studies are carried out by conservation scientists
>and are mainly focused on theoretical aspects. Unfortunately,
>however, there is little information on how microclimate frames are
>actually made and which materials are being used. I am particularly
>finding it very difficult to obtain a list of sealing materials that
>are currently considered for microclimate frames.

For context I am in the USA, a conservator in a regional center,
familiar, interested, and focused with all parts of your inquiry. I
believe there are a multitude of methods for achieving microclimate
enclosures. I use three in the circumstances you describe, no, I use
two, and I look for the opportunity of using the third. For me it
all depends on the condition of the rebate and back of frame, the
width of the rebate, plus the shape of aperture, since not all are
rectangular.

1. In my context some micro-climates are for short loans to
different climate places and I might use Marvelseal bonded to the
the glazing (often Tru-Vue Optium Museum acrylic) with hot-melt glue
(3-M, I do not have the grade handy). It is a bit more complex of a
process, but you get the gist. The flaps of Marvelseal are heat
sealed onto another Marvelseal sheet placed over the back of the
object. Credit to Hugh Phelps (Nat Gal.DC.).

A build-up on the back of the frame is usually required with all
methods described to increase the depth of the rebate (rabbit, how
ever you say it): I use sugar pine for build-ups, a USA wood that is
clear, straight, and light-weight, mitered at the corners, glued
with yellow glue, then joined with splines into table sawn slots,
using yellow glue again. Everything yellow glued (a PVA aliphatic
resin), is clamped [cramped?]. The vocabulary is variable to me.

2. I use gaskets of Volara, not strips that have corner gaps, I cut
the Volara from whole sheets. A rectangle of black Volara goes
against the rebate, install the glazing, fit mitered wood and
painted spacers (I have given up on acrylic spacers), fit felt
strips on the spacers, and fit the art. A build-up has already been
fitted with a rectangle Volara (not strips) between the build-up and
frame back. The back is sealed with an aluminum panel that seats
into a rebate cut in the build-up back, and a rectangular gasket of
Volara is fitted between the aluminum and build-up. I hope you get
the gist on that method.

3. In my next method I look forward to using a Z shaped bent steel
sheet with corner welds to fit a given rebate, plus gasket,
build-up, gasket, aluminum back panel secured into a gasketed rebate
cut into the build-up.

I hope some of these suggestions may help your situation and open
the subject up, though I find the small specifics are difficult to
describe in short messages.

Hugh Glover
Williamstown Art Conservation Center, MA. USA


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                  Conservation DistList Instance 25:4
                   Distributed: Monday, June 27, 2011
                        Message Id: cdl-25-4-005
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