Injectable foam for furniture

Christian Imhoff <imhoff_c [at] hotmail__com> writes

>... Very accurate
>indications allowed us to build a transparent PMMA negative mould
>that represents the upholstery's original shape. Putting this
>negative mould on the conserved upholstery (= positive mould) results
>in voids in between, which we want to fill by injecting a foam that
>best fulfills conservational requirements.

To my knowledge injectable foams are polyurethane. The expansion of
the foam is exothermic and can generate a lot of heat which is
undesirable in proximity to objects. Several article have been
written on its use and failure in conjunction with Archeological
digs. However you are proposing pre-moulding and then using the form
in conjunction with the object. Polyurethane off gasses and becomes
acidic over time. Additionally in conjunction with high humidity it
can go through cycles of weeping and wetting, as it shrinks and
deforms.  This is detrimental to the item.

I would recommend using a bread knife to carve the correct
shape/form in polyethylene foam, commonly called ethafoam, and then
pad that with 'Dacron' or a needle punched polyester webbing, then a
flannelette cloth and the original conserved textile, ensuring there
is no tension on the original textile.

There are many documents on mannequin making, forming ethafoam, and
using ethafoam shapes for ethnographic support and storage. The
detailed instructions can be adapted for use in furniture use as you
are seeking to conserve the design and intent of the maker and the
item will no longer be in use.

Victoria Gill
Conservator
Heritage consultant
39 Ponce St
San Lorenzo
Makati Manila
+63 28402590


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                  Conservation DistList Instance 23:42
                 Distributed: Wednesday, April 28, 2010
                       Message Id: cdl-23-42-005
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