Installation!

I can’t figure out what I’ve done, but I deleted my text from last Friday (didn’t mean to).  Anyway, these are the models finished.  I installed the head louse today and the photos are at the end.

Cat Flea

Deer Tick

Pubic Louse

Bedbug

Head Louse

Drama On the High Flea

Sorry about the title! But yesterday, the unspeakable happened: the flea broke loose from its mount and crashed to the floor!  Epoxy legs broke away and shot over the floor, parts of the comb went missing for hours, hairs were out missing on the floor, and generally, it looked pretty sad.

Flea model just after the fall

I don’t know about other types of work, but in museum work, sometimes there are dramatic accidents.  For instance, a graduate student was studying one of the duck-billed dinosaurs at the American Museum in New York.  He was studying the skull of the “type specimen”, a very important item in the collection from which all others fossils of the same species are identified.  Somehow, the pad on which the  skull was laying got hooked onto his chair and when he pushed away from the table, the pad and the skull came with him, crashing to the floor.  The skull broke into thousands of pieces.  The unfortunate student took a leave of absence from his studies and spent the next 6 months in the museum gluing the skull back together.

Last year when I was working on the Point Pelee diorama, I wrote in my blog about another preparator’s disaster.  You can read about it here:

http://jamesperrywilson.wordpress.com/2009/12/23/ray-delucia/

So, what I’m saying is that occasionally, things like this happen.  I was lucky that it wasn’t on the day of the installation.  I am also glad that the models are made mostly of 5 minute epoxy which can be repaired easily and quickly.  The crux of the weakness in the mount was my desire to hide the supporting structure.  I struggled with the problem of how to support all of the models.  Every other model I’ve seen has a support rod going right up into the body (at the Peabody we refer to this kind of mount as a lollypop!).  I wanted to try to do something different if possible.  In the case of the bedbug, it was too heavy and unwieldy, so I used the traditional method with a support rod right up into the body.  The only thing I could do was put the rod in the middle of the legs, so it is somewhat hidden by them.

The other three models are hung on the plexi rod hairs.  The plexi rods are all either airbrushed or sanded (to simulate white cat fur) but they are translucent.   Any solid supporting rod drilled into the plexi will be seen, so I decided I would try hanging the models on narrow 1/4″ plexi rod drilled into the plexi hairs as the mount.  My hope was that the 1/4″ plexi would disappear when glued into the larger plexi hair.  This worked to some extent, but it wasn’t perfect, the drill holes were still visible. In the case of the flea, there were two plexi rods drilled and glued into the body from hairs coming up alongside the body.

Flea model before the fall (note the two plexi rod mounts)

Hiding mounts has been a badge of honor with museum preparators  and taxidermists for many years.  My mentor, Ralph Morrill, mounted a wood stork in our Florida Everglades diorama by running a strong wire down the primary feather shaft of its outstretched wing.  The wire is drilled into a support behind the wall of the diorama and is invisible to the viewer.  The bird looks weightless in mid-air.  In 1947, George Adams, the taxidermist at the American Museum of Natural History, mounted the timber wolves in a diorama in the North American Mammal Hall.  Each looks as if they were defying gravity, airborne in mid-stride.  Each is supported by one rod coming out of one foot and may be the most extraordinary pair of taxidermy mounts in a museum display.  Write me with your favorites!

Well, back to the flea.  A lot of work on these models is trial and error.  In this case, the small diameter plexi mounts weren’t strong enough and I learned by my failed experiment.  I cut two stainless steel rods and inserted them into the plexi hairs.  Surprisingly, they don’t really show any more than the 1/4″ plexi rods, but I know they will never let go.

Model glued together again

A Hairy Weekend

Inserting hair (note the red eyes!)

I spent the whole weekend gluing monofilament hair into the bedbug abdomen.  There was a ton of preparation getting ready for this.  I had two volunteers, Kevin Massari and Nina Petrochko, cutting 1/2″ sections of monofilament for hours on end.  As a note, I should mention Bill Smalley, who cut lighter gauge monofilament for the legs, Stephanie Loeb who drilled and inserted insect pins on the flea legs, and Maishe Dickman, who fashioned the setae for the flea by turning long pins in a drill on a disc sander to get a finely graded taper and who went on-line and bought porcupine quills to use as setae for the flea.

I spent hours drilling tiny holes for the monofilament.   First I used homemade drills out of insect pins flattened at the tip and sanded to a diagonal because I was breaking the tiny drills (about $3 each).  As I glued the hair into these holes, I discovered the insect pin drills didn’t leave clean holes and the hairs were difficult to insert.  I then redrilled all the holes with a #70 drill to clean them out.  This took less time than fussing over each hair and I didn’t break a single drill.

In 2 eight hour sessions, I completely finished the ventral side of the abdomen and I am more than half way through the dorsal side.  I ran out of hair though, so I hope Kevin or Nina show up this week.  I cut some myself tonight and will insert those tomorrow night.  I probably need another 500 more.

I have learned from making models that hair insertion is very important.  I have done several facial reconstructions of fossil hominids and one of King Tut for National Geographic.    I’m still learning how to make these models look most realstic, but I know it is much more effective to insert each hair individually over the head than to use a wig.  In the case of the insect models, the hair is important as a creepy factor and worth the time and effort to put on.

This week at work, I will grapple with some of the other hair.  I have to find something that will simulate the long hair that springs from the side and bottom of the pubic louse.  Any ideas out there?

Pubic louse hair

Colored Silicone

I am using Home Depot clear silicone caulk to make the skin for the base of the models and for some intrinsic detail.  I bought a case of silicone caulk-the smelly kind that off-gasses acetic acid.  (I find the newer type that evaporates alcohol to be less effective).  One of my previous blogs was about going to the cadaver lab to look at scalp and pubic skin under the microscope.  I took two 16X16″ clay tablets to “sculpt” my notes in the lab since I couldn’t take even a microscopic section of human skin out of the medical school.  Once the skin sculpting was completed, I made plaster molds of them.

plaster mold of the sculpted pubic skin

I dry the plaster thoroughly and apply a coating of butcher’s wax.  After buffing it into the plaster, I add a light coating of vaseline.  The mold is ready for the silicone.  For the 16X16 mold, I emptied three tubes of silicone caulk into a plastic container and add colorant.  I bought silicone colorant from a prosthetics supply company (Factor II).

Silicone colorant used in prosthetics

These colors are very saturated and just a little is needed to color a lot of silicone.  By controlling how much is added, I can get a very realistic translucent color.  I use a spatula to apply it into the mold.  I found this to be a little tricky.  I want a fairly even coating so I can add more highly saturated color as a second layer.  I found that if I wait about 10 minutes, a skin forms on top of the silicone and with water on my fingers, I can push the silicone around enough so the layer is pretty even.

First layer of silicone in the plaster mold.

I will wait over the weekend to make sure the silicone cures all the way through.  I will pull it out of the mold and assess whether I should add a second layer or not.  Finally, I will back it up with either plaster or bondo.

One other application for colored I have found useful is to use it intrinsically in the insect casts to simulate internal organs or detail.  In the case of the pubic louse, there are sensors that are connected by a network of channels.  I used colored silicone to produce these.  Tomorrow, I will use a scalpel to cut the sides of the channels cleanly.

Silicone "channels" inside pubic louse cast.

Intrinsic/Extrinsic Painting

Today I started painting the bedbug.  I did a practice run on a reject cast first.  I tried painting with polyester resin and pigment extrinsically and found that it didn’t look right.  I thought that painting with the resin would make the color translucent and therefore it would work extrinsically, but I was wrong.  I decided to paint intrinsically, or inside the cast for the best results.  I use a specific colorant made for resins.  For the bedbug, I mixed a red and a blue for a bluish brown.  I load the brush with catalyzed resin (I double the amount of catalyst so it will set up in thin layers)  and pick up some of the pigment or vice versa and then apply it to the inside of the cast.

Epoxy cast of the bedbug abdomen before paint

Bedbug abdomen painted

As you can see, the intrinsic painting isn’t perfect and I will go back and touch it up intrinsically, but I also found that applying a lightly pigmented coat of resin extrinsically helps soften the irregularities.  I am fairly confident I can get good results with this method.

 

Technical Learning Curve

So, after writing up the last blog about casting with the vacuform insert and epoxy, I was able to work up an undersized vacuform prototype from the pubic louse sculpture.

It’s a long story, but I had to make an intermediate mold and cast of the louse sculpture before I can make the final mold in silicone rubber.  I made this intermediate mold in alginate and cast in plaster.  I removed the plaster cast this morning and was able to keep the alginate intact.  I had to work fast because the alginate won’t last long and felt very dry to the touch.  I laid in a thin sheet of dental wax and heated it to fit in the alginate mold.  I poured plaster over the wax.  When it sets up, I’ll peel the wax away and I will have an undersized form to vacuform from.

Alginate mold of pubic louse with wax sheeting laid inside

Plaster poured over wax

I’ll let you know how this works (or not) in a week when I get the silicone mold finished.

Grinding Out

I’ve got about 6 weeks to go to finish 4 models.  I am getting a lot of work done, but I’ve got a long way to go.  I looked at a photo of the bedbug today and was a bit depressed to see that I will have to cover every square mm of its body with hair!

I have cast both halves of the bedbug using the vacuform insert and 5 minute epoxy in the mold.  It’s not perfect, I will have to put in a number of hours of patching and sanding the cast.  As I cast more, I get better casts, so by the time I get to the lice casting, I should be a bit more up to speed.

I had two volunteers in today, Stephanie Loeb and Nina Petrochko.  Nina and I cast the second half of the bedbug and Stephanie took photos.  Here they are:

Plaster mold of half the bedbug abdomen

The mold was prepared with butcher’s wax and vaseline.  I mixed 3 cups of 5 minute epoxy with brown oil paint.

Five mInute epoxy poured into the mold. Before the vacuform insert is put in, epoxy is spatulaed up on the sides.

Vacuform insert put into mold

Nina and I push down on vacuform insert displacing epoxy up the sides of the mold.

If I had more time, I would shave the plaster form used in the vacuforming so the insert would fit better.  The lice are smaller than the bedbug and I should be able to undersize those before I make the vacuform insert.