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Mammoth Tusk Prep


Ptychodus04

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@StevenJDennis brought me quite the project. It's a central Texas mammoth tusk that is in terrible shape! Texas tusks are as close to the complete opposite in preservation as compared to Siberian or Alaskan tusks. They are always brittle, broken, and just looking for an excuse to fall apart. Props to Steven for rescuing this monster from a terrible fate in the back of an old man's shed!

 

The pics below show the tusk in the sate of preservation as they arrived to me. I have spent the last week with the fragments on end literally pouring medium viscosity PVA solution (about as thick as 20w 20 motor oil) into the cracks in an effort to stabilize them. 1 gallon later and they are beginning to toughen up a bit. PVA application will continue until the fragments will no longer absorb the solution. Then, I will attempt reassembly of the fragments. Unfortunately, there has been serious degradation of the fragments in many places. More to come!

 

 

IMG_3690.JPG

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Your description of tusk material found in Texas is accurate.  You only left out that you can look at it with the 'wrong expression' and it will crumble even more.  :D   They drink a lot...of consolidant.

 

:popcorn:

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35 minutes ago, JohnJ said:

Your description of tusk material found in Texas is accurate.  You only left out that you can look at it with the 'wrong expression' and it will crumble even more.  :D   They drink a lot...of consolidant.

 

:popcorn:

 

Very true! I looked sourly at another fossil and the tusk assumed my glare was directed at it and a piece fell off! This stuff drinks more than a sailor on shore leave.

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I have, unfortunately, seen all too many Texas proboscidean tusks that look just like that one!  When they're in that condition, they're almost past saving!  Trying to consolidate using PVA can be a downright expensive chore!

 

Good luck!

 

-Joe

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1 hour ago, Fruitbat said:

I have, unfortunately, seen all too many Texas proboscidean tusks that look just like that one!  When they're in that condition, they're almost past saving!  Trying to consolidate using PVA can be a downright expensive chore!

 

Good luck!

 

-Joe

 

I agree Joe, it can get out of hand. Thankfully, these pieces seem to be consolidating well and are beginning to solidify. I'm about to switch to a thick solution to pour into the big cracks. Then, I'm planning to mix up some PVA glue to assemble the pieces. This should tie everything together well since there will be about as much plastic inside as there is tusk when I'm finished. I'll have to build one heck of an armature to hold the tusk while the PVA dries!

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Looks like the ultimate jigsaw puzzle to me

 

I am looking forward to seeing your end result, best of luck ! :)

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The smaller bits are pretty well consolidated now. Last night, the construction began. Of course none of the 10kyo jigsaw puzzle pieces fit together correctly. With the large amount of plastic inside this tusk, I feel that Paleobond is the best option for adhesive. There's plenty for it to grab onto and make a good bond and the fast set allows me to strategically employ Apoxie Sculpt on the areas where the fragments don't make contact at all. For smaller gaps, I'm applying some VERY thick (think cold honey) PVA solution to lock it all together.

 

It's not going to win any beauty contests but it's going to become a tusk again!

IMG_3697.JPG

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Wow!  Your a braver man than I.  I wish you the best of luck.  I can also see that you are the man for the job.

 

RB

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Know what you mean, that is a monster job that onlly an expert like you should tackle.  This a portion of a Mastodon from the Sulphur many, many years ago before I had means to properly keep it from flaking into a million pieces. Back in the day, clear varnish was used, which is now turning an unnatural yellow color. Thought about using a mild stripper to remove what I can but not sure if I need to re-coat or leave as is hoping the varnish has penetrated any cracks and will be good to go? 

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I've seen this many times. I worked on a slab from the Sulphur that had a bunch of mosasaur verts and ribs where varnish had been applied 20 years prior. It was doing the same thing. I employed rubbing alcohol in large quantities and a stiff brush to dissolve and remove the surface varnish and then re-consolidated with PVA. It took a long time but turned out well.

 

A few more hours on the bench last night found me with another large section of tusk together with Apoxie Sculpt in strategic places for support. All said and done, this thing is going to be about 6 feet long! I'm going to have to rearrange my prep station for this thing to fit on the bench!! Notice the paint rollers providing support for the curvature of the tusk. Rats ate through my sandbags at my old house and I have never gotten around to replacing them. The rollers crush just enough to provide good point support.

Tusk 2.jpg

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Finished up the mammoth tusk prep today. Unfortunately, the middle section was so damaged on both ends that there's no good surface to adhere to. So, this guy is going to stay in 3 pieces... better than the 7 it was in originally and we saved it from the landfill!

 

Next up is a nice tooth and jaw piece from the same mammoth that is covered in a conglomerate that is like concrete!!IMG_3701.JPG

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Now, the jaw fragment with the big tooth... Concrete hard matrix, Fun. I'm attacking the sand around the gravel one stone at a time with my CP9361. Unfortunately, the matrix is WAY harder than the tooth. 

 

Slow and steady will definitely win this race.

 

IMG_3702.JPG

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Uncle Siphuncle

That's pretty dang cool looking.  I'd be tempted to leave the matrix in place, at least on one side.  I'm just a fan of pebble conglomerate on Pleistocene bones.  I've scribed bones exploded inside sandstone clumps as found.  At times I had to expose half a square inch, stop, wick superglue into the cracks, wait, then proceed.

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8 hours ago, Uncle Siphuncle said:

That's pretty dang cool looking.  I'd be tempted to leave the matrix in place, at least on one side.  I'm just a fan of pebble conglomerate on Pleistocene bones.  I've scribed bones exploded inside sandstone clumps as found.  At times I had to expose half a square inch, stop, wick superglue into the cracks, wait, then proceed.

 

Those kinds of preps are always fun, in a masochistic way. I've had a few like that where you spend more time consolidating and keeping it from falling apart than you do removing matrix. This one shouldn't be that bad since it appears to be fairly stable.

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Wow!  You sure do tackle the 'hard' projects.  Pun intended.  Im also with Uncle Syphuncle, I like his idea of leaving some rock on the piece.  Good luck

 

RB

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1 hour ago, RJB said:

Wow!  You sure do tackle the 'hard' projects.  Pun intended.  Im also with Uncle Syphuncle, I like his idea of leaving some rock on the piece.  Good luck

 

RB

 

Hee hee. Don't go into comedy... stick to the crab prepping. :D

 

I personally can't stand matrix left on a fossil unless it is required for stability or makes a really cool mounting surface. To each his own as they say.

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Uncle Siphuncle

I make matrix decisions on a per case basis.  I'm much more likely to leave matrix on a Pleistocene specimen of an extant form, like horse or bison, to serve as a "proof seal" of age to appease any doubters.

 

I'm attaching photos of a few things laying around my office.  The first is a Bison (?) axis.  The bone was pretty weak and flaky, so I didn't prep out the whole bone.

image.jpeg

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Uncle Siphuncle

Next is what I'm guessing is a Paramylodon thoracic.  This thing had just an inch of spinous process jutting out of a 10 lb ball of hard clay, sandstone and conglomerate. The bone was very weak, and essentually pulverized in place, supported by said matrix.  This one required exposing just a little at a time.  It had a "superglue drinking problem" and sucked down 10-12 tubes.  In the end I removed most of the matrix and left just a small pedestal because I don't see many complete sloth verts.  Rugged and gnarly, it fills its own niche in my collection.

image.jpeg

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Uncle Siphuncle

Here's an ugly dorsal view of the same vert...almost as painful to see as a Danny Trejo movie in HD...

image.jpeg

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Uncle Siphuncle

Finally, here is a horse mandible that was completely covered with hard matrix.  I cleaned off one side and left it "framed" with remaining matrix as much as I could.  

 

As you mentioned, Kris, to each his own, and I always enjoy seeing your preps.  Keep 'em coming!

image.jpeg

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Very nice specimens. Good point on the extant species front. That makes total sense.

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Hi @Ptychodus04

 

Quoted from @RJB "  I can also see that you are the man for the job. " amazing work and very well done indeed. 

 

I’m especially pleased for your post as I’m hoping to return to this straight-tusked elephant (Palaeoloxodon antiquus) tusk some time later in the year.

 

straight-tusked elephant (Palaeoloxodon antiquus) 1a.jpgstraight-tusked elephant (Palaeoloxodon antiquus) 1b.jpg

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