Consolidants and reversibility

A consolidant soaks into crumbly matrix or bone and hardens it; an adhesive joins two pieces. The conservation principle that matters most to a collector is reversibility: whatever you add should be removable later by someone with the right solvent, without taking the fossil with it.

Paraloid B-72 is an ethyl methacrylate co-polymer dissolved in acetone (or ethanol for slower work). At 2–5 % it is a penetrating consolidant; at 25–50 % it is a gap-filling adhesive. It stays clear, does not yellow, and dissolves again in acetone years later. It is the default choice in museum preparation labs for good reason.

Butvar B-76 is a polyvinyl butyral dissolved in ethanol or acetone. It is slightly more flexible than B-72 and is favoured for field consolidation of wet bone; it too is reversible in its solvent. Vinac B-15 (polyvinyl acetate) was the older standard and is still found on legacy specimens.

PaleoBond and other cyanoacrylates (“super glue”) cure fast and hold hard, which is why field crews use them. They are not practically reversible: acetone and commercial debonders soften them slowly and can stain porous matrix. Use them where speed matters and note it on the record; do not use them as a consolidant on a piece that might be prepared further or studied.

Epoxies and putties (Apoxie Sculpt, Magic-Sculpt) are fillers, not consolidants, and are permanent. Their extent is what the restoration percentage on your record describes.

Whatever you use, write it down. Stratum's Preparation tab lists consolidants by name so the disclosure, the certificate and the next preparator all read the same thing.