Removing polyurethane foam from brick

Petra Nirmaier <petra.nirmaier [at] lu__ch> writes

>We have a part of a medieval brick wall that had been block-lifted
>using polyurethane foam about 30 years ago. ...

You may be able to expose the entire brick to accelerated UV aging.
The UV will decompose the crosslinks within the polyurethane foam,
causing it to essentially "dry rot".  At this point, the urethane
should become brittle enough to be mechanically removed.  Since you
are dealing with a foam, you may need to expose the brick to the UV
aging in stages, removing a little bit of material each time (the
nature of the foam is such that it will refract the UV and not allow
it to penetrate well to other cellular structures within the foam).

Jamie Talbert
Chemical Process Engineer
Archer Advanced Rubber Components
Winston Salem, NC


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                  Conservation DistList Instance 26:48
                    Distributed: Sunday, May 5, 2013
                       Message Id: cdl-26-48-002
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