April
29, 2005 06:13 PM
posted
by Yvonne Wilson
Back to
the big jacket with the Camptosaurus torso.
I got the
okay to destroy the plant fossils. They are not identifiable
according to a visiting paleobotanist (thanks Mandy). I like
going through this section because the plants create layers
within this very solid sandstone. The layering makes the rock
break apart much easier, and I can move much more quickly. Pretty
soon I find a flat section of bone that must be the scapula
(shoulder blade).
Beside the
scapula I uncover a large crack in the rock. I pry the crack
open, and pull the rock away from the jacket. Unfortunately,
a chunk of scapula sticks to the block of rock I am removing.
It would have come off cleanly but for the fact that the scapula
has been plastered to the rock. Apparently the block
of rock had been fully removed, then glued in back into place
with a layer of plaster. Why couldn't they have left it alone?

In this second picture you can also see that I have uncovered
the layer of latex and sand bags in this portion of the jacket.

April
24, 2005 05:50 PM
posted
by Yvonne Wilson
I have set
George with the task of jacketing the block that contains the
hips. There is nothing protecting the bone the way it is now,
nor anything to really keep the block together. The plaster
that was smeared between the broken pieces of rock is eighty
years old. George applies the burlap and plaster over the latex
(I used the same method with the hips as for the big jacket.).
When that is dry, he flips it over.
Here is the ridiculous looking result:

There is a big block of plaster and wood on top that was used
as a pedestal when it all was on the ground. The pedestal has
got to go, though I am not ready to attack the block yet. I
do not want this weight sitting over the bones.
April
17, 2005 12:03 PM
posted
by Yvonne Wilson

I have been
spending a good amount of time just buzzing and whacking excess
rock from the fossil jacket. I will remark on it a thousand
times, but the strength of the rock is almost unbelievable.
Happily, it preserves the bone nicely, but it is a bear to get
through. Check out my fancy getup: earplugs AND earphones to
block the constant roar of the equipment, goggles to stop the
flying bits of rock, mask to keep out the dust, a bandana to
keep the grit out of your hair, and an anti-vibration Darth
Vader type glove. Don't I look beautiful?
By the way,
please notice that we have started dismantling a second wall-mounted
dinosaur. Behind me is the case from the Dryosaurus.
Norman has removed the legs already, leaving a scar and a gaping
hole.

I'm still
contemplating the tendons. The vertebrae (back bones) cannot
be separated without breaking them. What to do? Depending upon
how things etch out, I may be able to make a mold of the tendons
in place on the bones, then remove the tendons and place them
into the mold. This will keep the tendons properly oriented
while allowing us to take apart the vertebrae. What happens
with them for the final mounting of the dinosaur? I'll get back
to you on that.
Time to
get back to work.

April
06, 2005 11:42 AM
posted
by Yvonne Wilson
It helps
to maintain a level "playing field" when preparing fossils.
Archaeologists do the same thing to make sure they preserve
the layering in their excavations. For a fossil preparator,
it makes things easier to see. In this case it will limit the
stresses on the jacket and the fossils by keeping the weight
evenly distributed. So I trim off rock with a hammer and chisel.
My arms ache with the effort at the end of the day, and I can
feel the ringing of the chisel in my hand even after I stop
to take a break.
With this
mindless work you get a little goofy. When I got off a particularly
large hunk of rock, I raised it above my head and paraded around
the lab with a loud "WOOHOO!" Ah, the simple pleasures in life!
April
03, 2005 11:29 AM
posted
by Yvonne Wilson
We had previously
seen ossified tendons on this specimen when the hip block broke
away from the jacket containing the torso. Now that I am working
back by that end of the jacket, I uncover more of these linguini-like
tendons. They criss-cross to form a stiff lattice around the
backbones. This helps support the weight of the tail.

The rounded
parts you see are the parts of the backbones that protrude towards
the side (transverse processes). Now that I see the tendons
link these processes tightly together, I am wondering how in
the world to remove everything. A challenge.
March
30, 2005 11:20 AM
posted
by Yvonne Wilson
With the
hardware out of the way, I can work my way into the plaster.
Using a combination of the airscribe, hammer and chisel, and
the cast cutter, I plow through it down to the level of the
rock.

Just looks like a hunk of rock now. Yet a dinosaur lurks beneath.

I attack the rock lump with hammer and chisel. On rock this
hard (arrrg!) this method is much faster than an airscribe.
Though I still feel like I am trying to wear away a mountain
with dress pin. There are several cracks in the rock that were
not visible on the front. Remember that originally the preparators
covered the front with a layer of pebble-encrusted plaster.
A large
block of rock comes off when I exploit one of the existing cracks.
This has a hash of plant fossils -- nothing pretty to look at.
Just a bunch of carbon films, with little detail. Okay, here
it is anyway. A picture is worth a thousand insults, right?
Plants are both to the right and left of the ruler.

I wish we had a paleobotanist available to check them out. Though
I cannot see anything worthwhile in these specimens, someone
with a trained eye might. They might also be significant in
that they are directly associated with the Camptosaurus.
I will hold off before whacking through them.
March
29, 2005 05:40 PM
posted
by Yvonne Wilson
Getting
into this jacket is quite a task. There is so much metal and
wood on this it is funny. The metal was just there to bind the
wooden board onto the back of the rock. It took a lot of prying
and cutting to remove just the hardware. For fun, here are pictures
of all the accessories accompanying the fossil jacket:


March
25, 2005 07:40 PM
posted
by Yvonne Wilson
The stinky
task ends and the messy task begins. (I have such a funky job.)
It is time to wrap the entire package of bones and rock in burlap
and plaster. I have found that colors in the plaster can help
you tell how close you are to bone, so I make the first layer
of the plaster jacket a nice shade of green.
George has
made jackets too in the field, so the two of us encase the Camptosaurus
in this protective shell. It is a preposterously messy process.

The end result looks like Shrek laid an egg.

The next day I wrap it in a second layer (white, not green)
with embedded wood for support. This can be flipped and opened
on the back side.
Here I have
rolled it over. The board is the same one we could see from
the back of the case. The gap is where I drilled through to
see the bone early in the project.

March
24, 2005 07:20 PM
posted
by Yvonne Wilson
Yuck. Time
for stinky stuff. To protect the bones from the vibrations of
the tools, I am layering the entire surface in latex rubber.
The uncured liquid rubber paints on in slow-drying layers that
stink of ammonia. Happily the smell goes away when it cures.
I can do all the stinky work under our fume hood, which sucks
all the vapors outside. Otherwise I'd gas out all the volunteers.
Post latex
painting:

Here you can see there are still areas that need to be supported.
This undercut is not safe for the bones.

My options for support here are to use expanding foam (like
we used for Samson), something solid like plaster, or sand glued
together with a consolidant fluid. The foam or consolidated
sand takes a day to dry, however. Plaster seems too rigid and
heavy. I decide to go with wet sand packed in plastic bags.
It's a quick and inexpensive choice.

Next I will
jacket the beast and flip it over...
March
20, 2005 07:01 PM
posted
by Yvonne Wilson
All the
parts that stuck out from the jacket and could be removed have
been removed. I still have a few portions of bone here and there
that cannot be taken off yet, but protrude too far to ignore.
I want these parts that stick out to stay safely in place, so
I encase them in plaster to immobilize them. First I wrap them
in foil to make the plaster easier to remove.

Here I have made a moat of white wax to hold the plaster against
the bone while it sets. The plaster will protect these parts
of the bone from getting snapped off.

March
19, 2005 06:45 PM
posted
by Yvonne Wilson
Now that
the jacket with the torso is in a workable position, I can really
start in on it. I want to attack it from the back, however.
This means rejacketing the front side in burlap and plaster
and flipping the whole thing over. But placing this on its front
side is somewhat dangerous. There are exposed ribs and vertebrae
(back bones) that hang over the body cavity with no support.
Flipped over, the weight of the rock could break all these pieces.
So I start removing all the bones that have an airspace below
them. Using the airscribe, I take off one rib from the left
side (Allen took off six earlier), and three from the right
side.
The right
hand ones I remove are mostly attached with plaster. They have
been previously prepped from the rock matrix. I notice one is
kind of odd. I thought that I broke it as I worked around it,
but it seems to have been previously broken. No big deal...that
is what glue is for. Until -- uh oh -- it doesn't seem to want
to go back together properly. Boy, do I feel stupid.
I don't
feel stupid for long. As I start removing shellac on the little
bit of rock still attached, I realize that this rib is not as
it should be. They globbed shellac over the bone and about a
quarter-size hunk of rock with it. What looked like a chunky
rib is really a chunk of rock with a tiny, graceful rib inside.
And what's more, they have turned the rib head backwards and
attached it to the rest with a big glob of plaster. THAT is
why the pieces don't fit. They aren't supposed to!
This is
the orientation I found the rib in. The entire left portion
was covered in shellac, making it all look like bone. Once I
got the shellac off the rock (the exposed rock is a pebbly white
horizontal stripe), it looks much different. Notice the awkward
break in the middle.

And this is the way it is supposed to look:

I feel much better now.
March
13, 2005 11:30 AM
posted
by Yvonne Wilson
I cut with
the reciprocating saw through each side of the case, just below
the top board. Allen and Alan (two guys that are taller than
I am) lifted the top off.
So we have
gone from here:

To here:

March
13, 2005 11:18 AM
posted
by Yvonne Wilson
Michael
and my volunteer Mike get to do the fun stuff. They get to rip
apart the remaining case.
Power tools
and hammers thunder through the lab!

Afterwards,
Michael said he had way too much fun. I think there is some
innate need for all living things to rip stuff apart. Ever watch
a puppy with a cardboard box?
This tail
(a plaster fake) is being tossed out. You can see the ribar
protruding past the break.

Bye bye
to Camptosaurus' case. He is committed to being a 3-D
mounted dinosaur. (He? She? Who knows? We know it's little as
Camptosauruses go, but we can't tell what gender it was.)
March
09, 2005 06:33 PM
posted
by Yvonne Wilson
All that
is left to prepare is the torso, which is mostly in the jacket.
I decided it was too dangerous to lift the case over the jacket,
so we are lifting the jacket up and out of the case. The coracoid
bone (next to the scapula, or shoulder blade) is sticking vertically
from the jacket. It is likely to break during the lift process,
so I have to remove it before the jacket goes anywhere.

In the above picture you can see large khaki straps draped over
the bones. These will help us lift the jacket. They get looped
onto a hook at the end of a chain hoist, which is mounted on
a nine-foot-high wheeled frame. We roll the frame over the corner
of the case so that the lift is as vertical as possible. It
is not completely vertical, though, so we use a piece of wood
to lever the jacket away from the side of the case.

Up and over

Settling it on the table

Rocking the jacket to pull out the lift straps

Many thanks
to Norm and Allen for their assistance moving the beast, and
to Christina for taking these pictures.
And in Amy's
words, "So the easy part is over."
March
06, 2005 06:36 PM
posted
by Yvonne Wilson
Finally
I have cut all the way around the jacket. It has been a tough
job, leaning over all day while chiseling and prying away the
wire-backed plaster. But going home tired at the end of the
day can be satisfying. I am enjoying myself.
The vibrations
have broken completely through the developing crack in the hip.
There was not much that could have been done. It was an old
break. By cutting a hole beside the portion of the jacket that
broke off, I am able to climb in and remove the broken piece.

What remains:

By cutting lines with the reciprocating saw, I am able to cut
around and remove the funny old-fashioned Camptosaurus
picture. It is a sculpted slab of plaster.

There is not much left attached to the case. We will trash the
tail because it is fake, and merely a sculpted plaster slab.
The bones are not even 3-dimensional.

March
04, 2005 05:43 PM
posted
by Yvonne Wilson
Now that
the case has been tipped on its back side, I have to first completely
detach the fossil jacket from the mount and case. I will also
set free the amusing, old kangaroo-style picture of the Camptosaurus.
I use a hammer and chisel, a crowbar, a drill, and the red reciprocating
saw (POWER TOOLS!).

The fun part is that I get to climb all over the "rock" face.
The not so fun part is trying to get through all the nailed-in
wood supports and ultra-thick plaster sections. Here I have
almost cut all the way around the jacket.

Despite the wooden slats we screwed to the back of the case
to support the jacket, it is sagging in the middle for some
reason. Not good. Further investigation reveals that the sag
is where the jacket ends and bare rock begins. It runs mostly
along an old break. Unfortunately, a crack develops through
the left ilium, the blade of the hip bone.

This is NOT the way I wanted it to go. But you work with what
life hands you. To prevent more sagging and further damage,
I jam sand bags underneath the area of the break.

Continuing with the freeing of the jacket, I have to keep cutting
through these almost randomly-placed wooden supports. These
wouldn't even be so bad except that the wire mesh is nailed
onto the wood, so I have to deal with wood, wire and nails along
with the plaster. I finally use a picture of the back of the
case to plan where I will cut. In this way I can minimize the
lumber and metal I have to cut through.

These pieces
of lumber are a laugh. It is obvious they used whatever scraps
they had on hand. Some pieces are painted black on one side,
and they run the gamut from small blocks to 2x2's to 2x6's,
of random lengths. But I suppose they ended up with a mount
that lasted all these years. I shouldn't complain. It gives
the project character.
March
03, 2005 05:46 PM
posted
by Yvonne Wilson
I had to
protect the ends of the right hand ribs. They were sticking
over the edge of the original jacket supporting the torso. Using
the classic jacketing technique, I dipped burlap strips into
plaster and smoothed these over the rock. They will dry into
a nice tough shell to keep the ribs safe.

And lastly before we tipped the case over, we took out the feet
and the right hand. These are sub-standard reproductions that
we hope to replace with casts from another Camptosaurus.

Sorry, but I can't show you the next step. We needed all the
hands we had to help tip the case over, so nobody was available
to take pictures. We attached metal banding behind the jacket
to secure it to the case. Then we screwed two long boards onto
the back of the case so that the jacket would not rest directly
on the floor. We strapped the case to Big Joe, the forklift,
and eased it onto its back side.