[NHCOLL-L:5567] Consolidating a large rock

[Pellegrini, Rodrigo]

Dear colleagues,

Two large dinosaur footprints in separate, large, very fine grained sandstone blocks were put on display outdoors (against my recommendation and despite my protests) by my museum last year, with no roof or other protection from the elements above.
After the winter, and the currently exceedingly hot summer, it is painfully obvious that one of the blocks is flaking all over, as not only are there flakes actively developing on the surface, but many flakes can be found all around the block, varying in size but averaging about 1" square.

I was wondering if anybody here had any thoughts on ways to consolidate the block to prevent further flaking, which I am attributing to freezing and thawing over the seasons.
Given the size of the block (about 6 to 7" thick by 5 to 6' long by about 4' wide), I would think a cyanoacrylate glue would be ill suited, especially given the fumes that it would generate on that scale.

I am currently favoring Acryloid B72 mixed in with acetone to a low viscosity, brushed on, as a solution.

Can anyone here suggest a better solution for consolidating and coating this large rock to prevent further flaking?
Even if no better options can be provided, can anyone think of a reason not to use Acryloid?

Thank you all for your time and suggestions,

Rod

Rodrigo Pellegrini
Registrar, Natural History Bureau
New Jersey State Museum
PO Box 530
Trenton, NJ 08625-0530
USA

Rodrigo.Pellegrini at sos.state.nj.us<mailto:Rodrigo.Pellegrini at sos.state.nj.us>

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