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Mosasaur prep, jaw section


snolly50

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PART 1, acquisition 

 

This piece was acquired via the "for sale" section of the Forum. The seller, @Fitch1979, Dries offered several jaw specimens, which were clearly superior to the mostly spurious Internet auction site examples. Dries provided some provenance on the fossil. It had resided in his family's private collection for over 26 years. It had been purchased at a gem and mineral show in Ghent from a collector who acquired the specimen in 1978. 

 

After a pleasant exchange with Dries, a bargain was struck and the specimen shipped on December 9, 2017. Since the piece was located in Belgium, arrival involved a seemingly interminable wait. Finally, the tracking indicated arrival at US Customs on December 29th. Then the real wait ensued. The tracking was not updated until January 22, 2018. At that time notice was given that the package had been turned over to the "postal operator." Curiously, it arrived on my SC doorstep that very day! It was a surprise to open the door and find the huge (shipping weight 28 lbs.) shipping box resting there.

 

Here is the image posted to the Forum offering the fossil for sale.

 

mosaBelgium.jpg.03d8c1d28dc52c176f4a03b1f61ef2cd.jpg

 

...to be continued

 

 

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VERY nice!  Personally, I would be very tempted to leave it just the way it IS!  It gives it a certain extra aura of authenticity.

 

-Joe

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Illigitimati non carborundum

Fruitbat's PDF Library

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Part 2, unboxing, initial impression and prep planning

 

Here is the large box that made the overseas journey.

 

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Opening, revealed boxes within boxes

 

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The fossil was well protected by a variety of packing materials. Notably wooden slats were employed as rigid protectors.

 

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Here is the specimen revealed

 

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The "bottom"

 

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The "back"

 

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A quick glance revealed a wonderful replacement tooth on display under a fractured section of bone. The piece on initial inspection was very exciting.

 

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The specimen weighs approximately 19 lbs. It is about 23" long and 8" in height. It varies in thickness but is roughly 4" thick. It is the left mandible. The already exposed side, which will be the ultimate display, is seen in the lingual aspect. Now, a plan for prepping must be formulated. My opinion was, the piece would best present, if the existing matrix between and behind the teeth was removed. I visualized the jaw section with its toothy surface freed, but with the supporting matrix left behind the mandible itself.

 

...to be continued

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15 minutes ago, Fruitbat said:

I would be very tempted to leave it just the way it IS!

Indeed, your comment is greatly appreciated. It reflects my view in part and I almost chose the "leave it be" option. As you will see, I could not help but meddle, I am satisfied I have left enough of the "out of the ground" appearance. However, this is certainly a project that will evoke a variety of opinion as to how to move forward - from "leave it alone" to "remove all matrix and attempt reconstruction."  

Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Part 3, Weapons of mass destruction, the prep begins

 

I needed a way to transport the matrix block safely, as I would be working outside due to the mess. I cobbled together a platform, cardboard stapled to some pieces of wood for rigidity. To make a cushy work surface, I filled a birdseed bag (plastic with reinforcing mesh) with sand. The sand I had available was very fine grained and the result was a hard cushion. I replaced the sand with a cast off foam pillow, cut to size.

 

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Here are some of the tools employed: PVA B-15 and small brush for application, Larger brush to whisk away debris/dust, pin vises with carbide needles, pointed and flat ground, Xacto knife, dust mask (a vapor/gas rated respirator was used when applying the PVA) and gloves for handling wet PVA coated parts.

 

PVA B-12 is known commercially as Vinac. My supply, as well as sound advice, was generously provided by @Ptychodus04 , Kris. 

 

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Here are the power tools utilized for bulk matrix removal. The Dremel is equipped with a carbide stylus that has been ground much smaller than the standard Dremel stylus. It is much more effective. The Dremel is nicely powerful, but unlike the ElectroStylus it is not ergonomic. Because of the top-heavy configuration of the Dremel, prolonged use will strain the operator's hand. However, it was so well suited to removing this matrix it was employed almost exclusively. 

 

DSCN2868ac.thumb.jpg.3bbe7970a2a87cc3f29ff85c533ae4dc.jpg

 

Given that the piece arrived in Winter and prep was performed outdoors, the initial efforts consisted of minor prep - exposing additional areas of the already visible bone. A carbide needle was utilized.

 

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The piece, minor clean-up done, was coated with the PVA solution. This was mixed very thin for penetration - one part PVA beads to 50 parts acetone. It was felt it would be prudent to stabilize the exposed fossil (especially he teeth with their evident fractures) before all the handling/vibration the next steps would require.

 

  DSCN2633ac.thumb.jpg.4eca6ffb38ecf7233aef343a13c97141.jpg

 

...to be continued

 

 

 

 

 

 

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Part 4, prep, bulk matrix removal

 

Here is a photo showing the channels started in an effort to isolate a chunk of matrix to be removed from the rest of the piece. This was an effort to minimize transmitted vibration across the fossil.

 

 DSCN2803ac.thumb.jpg.8af120928a7c2025abec00fdbe09a930.jpg

 

The Dremel is employed to chip/pulverize the selected area

 

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Here are examples of matrix removed as a block, not pulverized; as it contained fossil material of interest  

 

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In removing matrix another replacement tooth was discovered 

 

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With the matrix between the teeth removed the slab was readied for the next step. The exposed bone was protected by encasing the lower half in bubble wrap.

 

 DSCN2820ac.thumb.jpg.1d7122aa0449566a2ef7e028b8310a16.jpg

 

Now, it was desirable to have the piece secured in an upright position in an effort to provide access to both sides of the fossil. To this end snolly called upon his amazing engineering skills to create the perfect solution. A small table-top clamp was pressed into service. However, it was not deep enough to properly secure the fossil. Therefore the clever alterations seen below were made. The cardboard "jaws" were lined with a sheet of foam - perfection!

 

DSCN2821ac.thumb.jpg.c3c13d8565e763c71fc3e1b29ef94da1.jpg

 

...to be continued

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Part 5, prep continues

 

With the fossil secured in an upright position work proceeds to remove the matrix backing the teeth. This is accomplished by cutting a channel next to the tooth using a carbide needle. This is an effort to isolate the tooth from the stresses of removing the large backing matrix.

 

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Of course the PVA applied to the previously exposed surfaces of the teeth had consolidated the matrix immediately surrounding the teeth. This made digging into that material difficult. It was found the best approach was to pierce the matrix at a ninety degree angle and then pry up. This allowed the needle to enter unconsolidated matrix and to break up the hardened plastic from below.

 

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Mostly freed

 

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The residual stubborn matrix was removed from the teeth

 

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The entire fossil was slathered in dilute PVA

 

DSCN2849ac.thumb.jpg.01b9969440207ae2a697224c38e98661.jpg

 

...to be continued

 

 

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Part 6, finished

 

Here is the finished fossil. Future efforts will include designing an appropriate stand and exploration and ID of some of the small fossils uncovered in the matrix. I hope this exercise in some small way will encourage others to undertake rewarding preparation work. The granular, sandy matrix of these Moroccan pieces is friable, easily worked. It is my believe that they make ideal projects for the novice prepper.

 

Left mandible, lingual aspect

Prognathodon sp

Maastrichtian

3rd phosphate layer

Oued Zen, Morocco

 

Her name is, Lillian.

 

DSC_7281acz.thumb.jpg.91b038ff9faaebcf952c7bfb571dd176.jpg

 

  

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Excellent report, Sir Snolly!

Great prep and ingenuity in it's execution!

Puts those fake jaws to absolute shame. 

Well done, sir. 

    Tim    VETERAN SHALE SPLITTER

   MOTM.png.61350469b02f439fd4d5d77c2c69da85.png      PaleoPartner.png.30c01982e09b0cc0b7d9d6a7a21f56c6.png.a600039856933851eeea617ca3f2d15f.png     Postmaster1.jpg.900efa599049929531fa81981f028e24.jpg    VFOTM.png.f1b09c78bf88298b009b0da14ef44cf0.png  VFOTM APRIL - 2015  

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"In every walk with nature one receives far more than he seeks."
John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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Always a distinct pleasure to see your ingenuity and careful application of skill converge, Snolly. Well done! :dinothumb:

...How to Philosophize with a Hammer

 

 

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Fantastic job, John!  Lillian will be a wonderful addition to your collection, I'm sure :)

 

So how many hours/days do you think you spent in total working on Lillian?

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Thanks to everyone for the kind comments. I greatly appreciate the approbation of the Forum's members.

 

@Monica Hello, I did not keep track of time spent. The project drug out as I awaited nice weather to work outside. However, even though the fossil itself is large; it probably took less total time than a medium sized Green River fish. It's just the nature of the Moroccan matrix. The Dremel can rip through that material with ease; moving large volumes in a short time. The most time on this project was the needle work close to the teeth in an effort to isolate them from the more aggressive engraver work. It is possible this step could have been skipped and power tools (engravers or air powered scribes) used exclusively; but I was taking no chances in fear of crumbling one of those beautiful teeth. The bone itself is substantial, but brittle. The matrix is riddled with small shards of bone that are almost as friable as the matrix. The second most time consuming task was the needle work removing spots of matrix from the already exposed bone. There were plenty of places where a little effort would uncover more bone surface.

 

My account failed emphasis of two important tools. The small Xacto blade was very useful in the final clean-up of the tooth surfaces. Also invaluable was a 35 year old Electrolux, long retired from house duty. It performed yeoman service at collecting the massive amount of matrix debris. Three full bags and a partial were collected by the vacuum. This material was "washed," dissolving all chunks and then searched for small inclusions. This yielded mostly tiny bone fragments, but a few surprises emerged. I will post these items when sorted and photographed.   

 

Again, I hope this fossil romp will encourage others to try prepping. I believe with simple tools and a little planning, acceptable results can be achieved by anyone with the time and interest.  

 

The next challenge is to find a display location and appropriate stand for Lillian.

 

Lillian? Well, she's a red dirt girl. Here is the inspiration for the name. This evocative, poignant tune is one of my favorites, as is Emmylou.

 

 

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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That looks like it was a really fun project.  and how can anyone not like the way snolly narerates.  (spelling?)

 

RB

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5 minutes ago, Fitch1979 said:

I just love what happened to the piece .. so great to see its enhancement!

Dries, Thank you for the kind assessment. Like @Fruitbat expressed in the first comment to this post, my initial impulse was to just leave it alone. It was a lovely fossil, that would display well in its original condition. However, I felt that having the teeth completely exposed made for a more dynamic "lifelike" display. At the right of the piece you may notice an area protruding from the "back" of the fossil. That is indeed the end of buccal aspect of the mandible. I was greatly tempted to start there and follow the bone exposing that area the entire length of the fossil. I refrained from doing so for several reasons. You will note the uneven shards of bone displayed along the upper jaw surface. This suggests that side of the mandible has multiple fractures, like the display side. That bone material proved to be much less stable than the previously exposed bone - at least at that upper margin. In addition, given the available areas for possible display of the fossil; it will only be viewed from one side. Therefore, retaining the added stability of that encasing matrix seemed prudent. Lastly, the prep had gone well without any disaster. Why tempt fate, quit while you are ahead! I hope my effort has achieved a nice balance of dramatic display while retaining the aura of antiquity, that "pulled from the earth" appeal.  

Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Thanks for the photo documentation. Great job! That's a beautiful fossil that is greatly enhanced by your prep.

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Outstanding work as usual, @snolly50.  Might I ask where you got the carbide tip for the Dremel and did you have to grind it down at all?  I have the same Dremel sitting in my garage and I have been trying to figure out how to improve the stock tip.

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9 hours ago, Sagebrush Steve said:

I have been trying to figure out how to improve the stock tip.

I got mine a while back from a guy in China. He emailed me after my purchase and reported that he had established a web site; stingertools.com 

His site reports he also sells on that auction site, seller name; mydiggingfossils.

I have found his points to be very useful in the Dremel device. 

 

 

Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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Part 7, a singular inclusion 

 

Several obvious inclusions were recovered during prep efforts. In addition the waste matrix was reduced in water in an effort to obtain smaller inclusions. One of the more curious finds is shown below. The "pointy" end emerged from the matrix and being noticed, an effort was made to extract the entire piece. Unfortunately, it broke into three pieces. This suggestively shaped object appears as one might imagine a coprolite. The surface is marked with striae. The larger grouping of these parallel depressions may be seem in the image depicting the entire object. The other images show close-ups of markings in other areas. The surface that is not marked appears very smooth. The entire piece is 1 4/16 inches at its longest. Opinions are sought from members, @GeschWhat with coprolite expertise. 

 

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Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See

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