Fossils

Christine Ianna <christinei [at] qm__qld__gov__au> writes

>I have been approached by a member of our Vertebrate Fossils section
>requesting advice on alternatives to PVA for consolidating and
>adhering large fossil specimens even smaller ones for that matter.

As an object conservator (mainly furniture) I have always hated all
PVAs that have been inconsiderately used on furniture.  A close joint
adhered with PVA is practically impossible to reverse, it swells all
right but if there is no place to swell into.

I know that B72 is beloved by the conservation profession, and I am
probably going to be flamed for what I am about to write but I feel
it should be said. B72 does not yellow and does not shrink and I
believe is supposed to last forever. One could add it does not stick
and it gasses.

Its Tg is supposed to be 40 degree C. but I have had experience of
it dramatically failing at 32 degrees C. (when an air conditioning
system packed up). Also because of its softness, it attracts dust.
Besides all that it is marvelous.

I am looking for alternatives; waiting for them I am back to the
old cellulose nitrate that yellows, and will fail in 100 years or
animal glues that yellow shrink and will fail in 300 years given an
adverse environment but they stick and are easy to reverse!

I have successfully glued mammoth bones with cellulose nitrate it
will yellow and probably will fall apart eventually.


                                  ***
                  Conservation DistList Instance 15:30
                 Distributed: Tuesday, October 9, 2001
                       Message Id: cdl-15-30-006
                                  ***