[Nhcoll-l] Best repair glue for bone specimens

[Fran Ritchie]

Hi Kayla,

Joachim beat me to a response! High tack fish glue is great, and Paraloid
B-72 is an extremely versatile adhesive that we use frequently in objects
conservation. The one thing I want to add to his information is that
Paraloid B-72 can be reversible using the same solvents. Sometimes it takes
a longer dwelling time, but if the bones are placed in an acetone chamber,
it should do the trick to release the adhesive. I've performed that trick
many times on objects, particularly ceramic pieces. If anyone has further
questions on this, don't hesitate to reach out.

You can buy Paraloid B-72 premade in little containers that look like nail
polish containers. This makes it very easy to use and apply. The solution
is 20% in acetone, which might be a little dilute for your purposes (this
is ideal for consolidating areas, as Joachim mentioned, and also for
labeling objects). To thicken, you could keep the lid off of the container
for a few minutes to allow the acetone to evaporate. Conversely, if it
becomes too thick or stringy, you can add drops of acetone and wait a bit
for it to dissolve, creating a less viscous solution.

In the States, it's available here
<https://museumservicescorporation.com/products/marking-varnishes> and here
<https://www.talasonline.com/Paraloid-B-72-Lacquer>. And as he explained,
you can make your own solutions in glass jars (with a well-gasketed lid) by
buying your own pellets. They are available here
<https://www.talasonline.com/Paraloid-B-72>. If you would like more
step-by-step on how to make it, I'd be happy to walk you through it. I just
gave a presentation during this past SPNHC meeting on the exact topic.

I also strongly advise against superglue, as well as anything used in the
human dental industry.

Best,
Fran
Chair of the SPNHC Conservation Committee

On Tue, Jul 25, 2023 at 2:47 AM Joachim Händel <
Joachim.Haendel at zns.uni-halle.de> wrote:

> Dear Kayla,
>
> the question here is whether the bonding should be reversible or not.
> For reversible bonding, I recommend fish glue - an excellent adhesive. It
> sticks strongly and dries quickly. You can dissolve the bond again with
> warm water.
>
> For non-reversible bonding, I recommend Paraloid B72 dissolved in ethyl
> acetate or acetone. This can also be used to fill defects and consolidate
> crumbly parts.
> If it is absolutely necessary, the adhesive can be dissolved again by
> soaking it in solvent for a longer period of time.
>
> If necessary, nitrocellulose glue can also be used. However, it is not so
> durable and turns slightly yellow after a few years (decades).
>
> I strongly advise against superglue, because you have to press the pieces
> together hard when gluing, which can damage the objects.
> Moreover, you can never dissolve it again
> All the best
> Joachim
>
> --
> Joachim Haendel
>
>
> Center of Natural History Collections
> of the Martin Luther University (ZNS)
> - Entomological Collection -
>
> Domplatz 4
> D-06099 Halle (Saale)
> Germany
>
> Phone:  +49 345 - 55 26 447
> Fax:  +49 345 - 55 27 248
> Email: joachim.haendel at zns.uni-halle.de
>
>
>
> >>> Kayla Ott <kzott at ucsc.edu> 24.07.2023, 23:24 >>>
> Hello everyone,
>
> Does anyone have recommendations on the best glue to use to repair bone
> specimens that have been broken? Something that would work to repair teeth
> that have fallen out of mandibles, vertebral columns that have had some
> spinous processes broken off with use, etc.
>
> This is for specimens in our reference teaching collection for
> undergraduate zooarchaeology courses which students are very hands on with,
> so the more durable, the better.
>
> Thanks!
>
> --
> Kayla Ott
> Pronouns: They/Them/Theirs
> Laboratory Operations and Facilities Manager
> Department of Anthropology
> University of California, Santa Cruz
> Phone: 831-459-1481
>
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