Stabilizing Small Fragment of Mastodon Tusk

[darrow]

This is a Mastodon tusk fragment I found this in a fresh water environment in early November.  It seemed relatively stable after cleaning, but over the past four months the uniform dark brown has taken on this mottled pattern.  I haven’t detected any instability, no flaking or crumbling, but it no longer sounds solid when tapped with a finger,  I assume cracks and fractures are propagating with progressive drying and differential shrinking. 

I know modern elephant ivory can develop cracks as it ages. So I assume it’s only a matter of time before this fragment starts to fall apart.  I have a couple pounds of Butvar B-98 but I have little experience with fossil ivory.  Should something like this be given time (months) to dry thoroughly before being consolidated?   is it okay to just dunk something like this in Butvar after the initial cleaning and 24 hours to dry?  I would have liked to retain the more attractive rich uniform brown color.

Darrow

[Harry Pristis]

Consolidate now!  The original color may be restored to a large degree.

There are extensive suggestions for consolidation in many threads on the forum.  Do a search.

[StevenJD]

@Ptychodus04 would probably know the best course of action.

[Ptychodus04]

I would suggest immediate consolidation. My preferred method is pouring on a thin solution of butvar and acetone.

 

if you are already experiencing cracking, I would not soak the specimen as this may loosen poorly cemented pieces.

[darrow]

It survived a 24 hr soak in a 5% wt/vol solution Butvar B-98 and 99.5% isopropanol.  

I put a mammoth tooth in over an hour ago and it's still outgassing a few steady streams of bubbles.  

[Harry Pristis]

2 hours ago, darrow said:

It survived a 24 hr soak in a 5% wt/vol solution Butvar B-98 and 99.5% isopropanol.  

I put a mammoth tooth in over an hour ago and it's still outgassing a few steady streams of bubbles.  

 

 

Good images.  Let us know how the alcohol works as a vehicle for the B-98.  I've never tried alcohol and am curious about how it mixes, how it dries, and if it produces drip-beads where it drains.  What does the proportion 5% wt/vol mean in terms of fluid ounces or other simple measure? 

[darrow]

On ‎2‎/‎22‎/‎2017 at 10:53 PM, Harry Pristis said:

 

Good images.  Let us know how the alcohol works as a vehicle for the B-98.  I've never tried alcohol and am curious about how it mixes, how it dries, and if it produces drip-beads where it drains.  What does the proportion 5% wt/vol mean in terms of fluid ounces or other simple measure? 

NOTE:  99.5% alcohol is typically only available from chemical supply company or electronics supply stores like Fry's.  Do not use the alcohol on the shelves at the local drugstore as it's only 70% or 91% pure, the balance being mostly water.

 

5% wt/vol solution is...

5 grams / 100 mL 

0.17637 oz / 3.3814 fl-oz

about 3.5 oz / 0.5 gal

 

I mixed this in a new clean empty 1 gal paint can with a lid so I could seal it.  The B-98 fully and completely dissolved in the alcohol resulting in a crystal clear solution, but the process can't not be rushed.  Mixing speeds things up a little, but I ended up periodically sprinkling a spoon full of the B-98 on the surface of the alcohol and just letting it dissolve on its own.  It probably took a couple hours to mix all the B-98 in, then I sealed the can and left it over night to make sure it was completely dissolved.  I think next time I might try just dumping in all the B-98 at once letting it clump in bottom then seal the can and have them put it on the shaker at the paint store.

 

The solution was easy to work with.  Dry time was slow enough that I could handle the pieces wet for five or ten minutes without them becoming tacky.  I could find no drips or beads anywhere although I suspect one could increase the solution % to the point where that would become a problem.  I was happy with the results.  These are "bottom" edges when they were drying where drips would have formed...

Darrow