|
More
Samson Logs: Fall
2005 | Summer
2005 | Spring
2005 | Fall
2004 | Summer
2004
Winter
2005/6 — click on any thumbnail for a larger image!
March 11, 2006
"Bone" Voyage, Samson!
Samson came to the Museum in May 2004 when the staff of PaleoLab were contracted to scientifically prepare it. With the work completed, the famous fossil was returned to its owner, Graham Lacey, an international businessman from the United Kingdom.
February
14, 2006 12:17 PM
posted
by Allen Shaw
Having
described in detail the molding and casting process by which
the lower jaws and other skull elements were replicated, I
can now take you through the same process by which Samson's
skull will be molded and cast. The skull of Samson is much
more intricate than any other mold we have created to date
and will require a lot of consideration on how many pieces
the mold will comprise and along which areas the mold will
need to be split for easy removal. Once a general idea has
been formed, we can now begin with a clay flange followed
by the rubber and then the fiberglass shell. This procedure
will be followed for every section of the mold. The images
below illustrate the beginnings of the skull mold.
Clay is placed in openings and along areas where the mold
will be split.
The first location where rubber will be applied will be
in one of the large cavities next to the braincase. This cavity
is in the lower left part of the image.
The cavity has a clay flange built around it and rubber
is poured in and built up along the sides.
Close up of cavity with first layer of rubber applied.
February
12, 2006 10:59 AM
posted
by Allen Shaw
The
mold is now finished and undergoes its first
casting. In this case we are using a liquid
plastic in two parts that when combined the
plastic sets in about 20 minutes and makes a
lightweight, durable cast.
After pouring the plastic into the mold and
waiting several hours for it to completely cure,
the mold is now being opened to remove the cast.
The rubber is being peeled back to expose
the cast.
Sometimes it takes at least two people to
remove the mold from intricate parts of the
cast without breaking the cast or damaging the
mold.
Cast of part of one of the lower jaws.
It is free at last.
Casts of both lower jaws with multiple elements
being cast and now in the process of being glued
back together.
February
07, 2006 10:00 AM
posted
by Allen Shaw
Now
that both sides are finished, the excess fiberglass
and rubber is trimmed and separated from their
respective halves. The skeletal element is then
set aside and the mold is cleaned thoroughly.
The mold is then put back together, holes are
drilled through it and bolts are used to fasten
the two halves together.
The fiberglass/resin shell has been removed
and the rubber is being pulled away from the
skeletal element.
The rubber parts of the mold after being separated
from the skeletal element. These two rubber
parts are both halves of one of the lower jaws.
Here you can see the real skull element (part
of the lower jaw) and each half of the rubber
mold.
The mold is put back together and then drilled
and bolted together for casting.
February
01, 2006 12:13 PM
posted
by Allen Shaw
A
resin/fiberglass shell is laid over the silicon
rubber mold to add support during the casting
process. The shell will do this by keeping the
rubber from sagging or shifting while the casting
material is poured and set.
The
fiberglass looks very much like a loose-weave
fabric. Combined with a liquid resin, the fiberglass
will become a hard, durable, structurally strong
shell. This process is achieved by painting
the resin onto the surface of the rubber followed
by a layer of fiberglass. The fiberglass is
loose enough that the resin passes through and
collects on its surface. A total of ten layers
of fiberglass are intermeshed with resin and
then allowed to set for several hours.
Once
the shell is finished, the skeletal element,
rubber, and shell are turned over and the whole
process begins again with several layers of
silicon rubber applied followed by another fiberglass
shell.
The fiberglass/resin shell is built up with layers of fiberglass
cloth and liquid resin. The green color is from a dye we decided
to use.
The element/mold/shell are turned over and
the clay is removed and the excess fiberglass
is trimmed back.
Several skeletal elements are turned over
and being prepared for the next phase of rubber
and fiberglass.
The first layer of rubber applied to the
other side.
The fiberglass/resin shell being applied
to the other side now that all the rubber has
been applied.
January
24, 2006 12:32 PM
posted
by Allen Shaw
Molding
of the skull and other skull elements has begun.
We have made molds and casts of most of the other
skull elements already. The lower jaws are currently
being setup along with the skull for their molds.
Molding is much more complex than I initially
imagined. First you decide where you want to separate
the element into two halves. Sometimes depending
on the complexity of the element, the mold can
comprise multiple sections. The mold of the skull
in this case will be comprised of 8-10 sections
because of all the intricate areas and deep openings.
Once you have decided where you will separate
the mold into two halves, a clay flange is built
up around the element to provide support for the
mold when the cast is poured. The images below
will better illustrate this process.
Now
that the flange is finished, a silicon rubber
is poured onto the surface of the element and
the clay flange. Initially, a thin layer is poured
and all air bubbles are removed so that the fine
detail from the element is captured. A second
and third layer of rubber is then applied in thicker
coats to add support to the mold.
After
the rubber cures the fiberglass and resin are
applied over the top of the rubber. Stay tuned
and I will further discuss this procedure once
we get that far.
The skull with a clay flange surrounding the
teeth in preparation for the rubber.
Section of the lower jaw with the clay flange
being applied.
Section of the lower jaw with the clay flange
built around it.
The first, thin layer of rubber poured on several
elements.
Closeup of the first, thin layer of rubber
on the jaw section (notice the teeth).
The application of the second thicker layer
of rubber over the first.
The jaw section completely covered with the
second thicker layer of rubber awaiting the final
layer.
January
13, 2006 12:12 PM
posted
by Allen Shaw
At
long last! Preparation of the skull is finished.
The only place left to prepare is along the top
where the foam continues to support the skull.
Restoration of the skull will now begin. It should
only take a few days to fill in any cracks or
missing pieces. We will then begin the molding
process on the skull. Here are just a few images
of Samson now that prep is finished.
Closeup of one side of the skull.
Preparation finished on skull.
Inside or palatal view of the skull.
January
04, 2006 05:16 PM
posted
by Allen Shaw
Welcome
to a New Year! Dan has been busy sculpting a portion
of one of the lower jaws. Both lower jaws of Samson
are complete except the very end of the tooth-bearing
portion (dentary) on the right side. There are
five and a half tooth sockets missing from the
front of the jaw. Dan sculpted a dense foam into
the desired shape and then covered the foam with
an epoxy/resin for color and to add texture to
the surface. Take a look and see the awesome job
he is doing to make the two jaws look symmetrical
and complete.
You can see the missing front section of the
right jaw on the left.
Here Dan is getting ready to attach the sculpted
section in place.
A view of the two jaws with the sculpted one
mirrored with the complete one.
Another view of the sculpted and complete jaws.
December
31, 2005 10:34 AM
posted
by Allen Shaw
Early
preparation when the skull was turned over a large
pathology showed up just over the eye. Now with
preparation coming to an end, the same pathology
has once more been exposed along with some other
odd features in the same area. Have a look.
Although difficult to see, the injuries are
located towards the bottom of the skull (as it
is sitting now) where you can see a number of
small openings within the bone. The large injury
is at the very bottom and creates a divot. Check
the other images to locate the placement exactly.
A closer view of the injured area. The opening
you can see within the bone is supposed to be
there but the large divot just below that is an
injury of some sort.
Here is the same injury from a different angle.
A close up of the injury.
December
15, 2005 12:22 PM
posted
by Allen Shaw
Samson
was rotated even more so preparation could continue.
How we rotated Samson.
December
10, 2005 03:50 AM
posted
by Allen Shaw
If
you remember, a large number of skull elements
actually separated from Samson's skull and were
discovered lying around the skull and skeleton.
These skull elements have all been prepared and
are now undergoing the molding process. A silicon
rubber is built up onto the surface of the bone
until it reaches a thick layer that can be removed
without tearing. Once the rubber cures, we apply
a resin/fiberglass shell on the outside of the
rubber that will hold the rubber from both sides
firmly together during the casting process.
Initially, each element is laid up with a clay
flange that will allow us to handle the mold much
easier during casting.
Several elements with a clay flange.
Liquid rubber is poured over the element and
the clay flange. Once the rubber cures another
coat will be pasted on until it reaches a certain
thickness.
Several elements that have the initial layer
of rubber applied and waiting to cure before more
rubber is added.
December
03, 2005 09:02 AM
posted
by Allen Shaw
Now
that most of the rock has been removed from one
side, I can begin to use the air abrasive again
to remove the really thin layer of rock that still
adheres to the surface. In the image below, I
have begun the process of air abrasion which has
really made a difference.
Air abrasion of the maxilla (tooth-bearing
bone in the skull).
More Samson Logs: Fall
2005 | Summer
2005 | Spring
2005 | Fall
2004 | Summer
2004 |
