Sturgeon glue and matte paint

Anne Apalnes Ornhoi <anne.ornhoi<-a t->niku< . >no> writes

>At the moment we are interested in making contact with others who
>are using/have been using sturgeon glue in conservation of matte
>paint and any current information regarding experience/problems
>using sturgeon glue.
>
>We would also like to make contact with institutions presently
>researching the use of sturgeon glue on matte paint.

For 4-5 years, I have been experimenting with the preparation and
use of isinglass from raw sturgeon air bladders obtained from a
fishery in New Brunswick, Canada.  See

    <URL:https://www.acadian-sturgeon.com>

Due to dwindling supplies of both dried collagen and fully processed
isinglass sheets obtained through European sources, and recent
legislation that has banned the import of this material into Canada,
conservators here can no longer obtain it easily, even at high cost.
We need to investigate alternative sources of the glue from our own
waters.  My own interest in this began through a colleague from New
Brunswick who made contact with the owner of the above fishery a few
years ago.  He was seeking a source of sturgeon glue for the
construction of Turkish bows.  Around the same time, I was starting
to learn the method of repairing tears in canvas paintings using
Heiber's thread-by-thread method, assembling the various necessary
tools and materials.  I obtained a few European samples (German,
Finnish) from US companies and from other colleagues here, but also
began to experiment with extracting the glue from the bladders from
Canada's east coast, sent to me both frozen and low-temperature
dried.

While formal adhesives testing and research has yet to determine
whether glue from any of our native sources is as reliable a
performer as Salianski or other European isinglass for the myriad of
conservation treatment purposes, I have used it combined with wheat
starch paste in Heiber's proportions to repair a few small tears,
and on its own for consolidating cracked and flaking oil paint in a
few cases.   I have so far observed its treatment properties to be
comparable to glue extracted from European sources, similarly
prepared.  Glue properties--no matter the species/source--are also
very dependent on preparation method, ie. collagen separation from
skin, extent of fat removal (amount of fat varies from bladder
specimen to specimen and is determined by time of fish harvest;
early to late season), temperature range and duration of extraction,
drying conditions of gelatin solution, to mention a few.  Collagen
from the bladders can also be effectively bleached, and the
extracted glue clarified using a variety of filtering methods.

By no means do I claim to be an expert either in the preparation or
use of isinglass as I still have much to learn about its optimal
preparation for our purposes, but my sense is that local--as in
native--sources of this natural adhesive could likely be sought in
any part of the world from fisheries that harvest sturgeon for meat
and caviar, despite variable species.  The processing of bladders
into glue takes some time and involves handling the raw fish organ
(it's not that bad!), but on average, a supply of dried processed
sheets that last for several treatments can be prepared in one
session.

If anyone wishes to contact me with their thoughts, suggestions or
experiences preparing and applying this glue, I would be very
interested to hear from you.

Jennifer Cheney, BSc., MAC, CAPC
Paintings Conservator, Private Practice
Toronto, Canada


                                  ***
                  Conservation DistList Instance 27:40
                  Distributed: Friday, April 18, 2014
                       Message Id: cdl-27-40-001
                                  ***