Hell creek rib prep completed! Warning, lots of pics!

[hadrosauridae]

It has taken me 8 months to finish this prep!  Now, thats not working straight through, I have had a lot of other things requiring my time, but I finally finished the prep and reconstruction of the original material!  I will post through the phases of this, from the start...

 

This is an indeterminate rib I recovered from the Hell creek formation, on a private ranch near Lemmon SD last year.  From what I have learned is that there is not enough diagnostic morphology to distinguish between an Edmontosaurus and a ceratopsian when its not associated with more of the skeleton.  

 

 

This is the rib, after exposing the surface limits.  About half was exposed before I started work.  Its on a very steep hillside, so I couldnt change position to photograph it without my shadow in the way.  I was really hoping the float on the left beside my hammer was the rib head, but it turned out to be a partial, separate rib.  It also turned out to be going 180 degrees the wrong way from the body of the rib.

 

 

 

I jacketed and extracted the rib, then collected all the float material beside it and at the bottom of the slope.

 

 

It took me 12 hours to remove it from the jacket and do the rough prep of the first 3 sections (the proximal end), which were the most intact pieces.  The matrix is a claystone, so it wasnt terrible to work through, but the bone was pretty weak and highly fractured.

 

With the matrix removed

 

Very highly fractured bone.  I had to soak in a lot of butvar just to take it out.

 

Even heavily consolidated, It still was too fragile to remove as a single piece, so I softened the glue everywhere there was a large gap.  That actually worked out really well because then I could concentrate on small portions.  The sections go right to left, top to bottom.  The distal end on the bottom left, and proximal on top right.

 

The start of prep on the first 3 sections.  These were the easy pieces to prep.

 

There was so much minutia work to rebuild these first sections. Complete separation of every fracture so that 100% of the matrix and consolidant can be removed in order to get the pieces to fit as well as possible. "Breaking" fossils in order to put them back together feels frustrating, but the result is so much better. I'm pretty sure this has a healed fracture.  There appears to be a line of bone remodelling with a noticeable deviation in rib angle.  Of course, part of the modern break goes right through the bone repair though.

 

 

 

 

The process of cleaning, separating, blasting away 100% of the matrix in order to reassemble, continued, section by section.  Some sections had a lot of tiny pieces.

 

The sections were reassembled, there were still gaps, so I used a nice "Hell creek brown" paleosculp to fill the cracks and provide further stabilization.

 

This would be the toughest portion for me.  You can see that after cleaning and positioning the 2 parts that this was actually missing a lot of material.  There was one, tiny spot of original connecting bone to give me a true spot work from.  Otherwise it would have been pure guesswork. 

 

I started with gluing the one true spot, and then packing a core of epoxy putty for stability.  There was no way I could have handled it with just the tiny glue point.

 

 

I had used the brown epoxy to filling all the tiny separations to give it a more natural look, but there were a few spots of missing bone.  Since I would be recreating those missing parts, I decided to use a grey epoxy to stand out and say "this is not original".  I outlined all the sections that were reassembled, just to give a visualization.  I counted 82 pieces, but I know from some of the earlier pictures that there were a lot of tiny bits that arent counted.  It was likely over 100 elements in this.

 

 

 

 

I kept the fossil in 2 sections until the very end to make working with it easier.  The final joint was a very clean and straight break so I knew it would be simple glue. Using the good old 3rd-hand sand bucket, I made the final glue joint.  Even though the top section was able to balance, I held the joint for several minutes, then added a couple strips of tape to final stabilization while the glue had 24 hours to fully cure.

 

And finally, today, here is the completed rib! It feels special since I did every step from exploration, discovery, excavation, jacketing, preparation and reconstruction. 

 

 

 

 

 

Even though the original material prep is complete, I still have work I want to do.  I'm excited to fabricate a new head and then weld an armature stand for display. I'm highly tempted to make a mold and cast once the head is complete, but that's a lot of latex and resin ($$$)

 

 

Edited May 7 by hadrosauridae

[aerogrower]

Been watching your progress on FB. Very nice work. Love the end result. Congrats!

[Jaybot]

Nice work!  In my experience, doing all of the steps is rewarding for sure.  Thanks for sharing

[old bones]

That's some real dedication! Wonderful results!

[Tidgy's Dad]

Nice work.

[FossilNerd]

That was quite the puzzle! Well done! 

[jpc]

This is a great show and tell about what it is like to work on Hell Creek slash Lance Fm material.  So often fractured with pieces just simply missing.  Nice work, hadr.    

[Ludwigia]

Very good work!

[Alex S.]

Great work! I've been following as well on social media. It's always nice to complete a prep. Do you know what shape of head you're going for? I have several different rib head shapes I could send you if you want. I am also going to use the 5 gallon bucket sand box I don't have the space to build a classic sand box so that will be perfect. 

[hadrosauridae]

14 minutes ago, Alex S. said:

Great work! I've been following as well on social media. It's always nice to complete a prep. Do you know what shape of head you're going for? I have several different rib head shapes I could send you if you want. I am also going to use the 5 gallon bucket sand box I don't have the space to build a classic sand box so that will be perfect. 

 

I'm look at something like this, as the most likely shape this would have had.  Just based on the overall rib shape, and the remaining start of the flare near the proximal end.

 

[Alex S.]

Looks correct to me. I'm excited to see the armature I've been meaning to try that but I have too many things on my plate so a jumbled display will have to do for now.