Hedgehog Cactus flowers


The flower petals were made with hot melt glue. The pink flowers have a colored light gel embedded in the hot melt glue. The “sepal” petals were made with a resin colorant mixed into the hot glue (I found that some oil paint doesn’t work well and separates when mixed into the hot glue). One end of #1 insect pins were pushed into the base of the petals and then the other end was drilled and pushed securely into the original wax base of the flower. I melted edges of the petals together to secure them together all around. More wax was used to smooth the base into the petals.


New and old. 


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Hedgehog Cactus Flowers


After finishing and installing the Desert Star flowers in the Desert diorama, Collin and I are shifting focus to the flowers on the Hedgehog Cactus. These flowers were created in the 1950’s by one of the “superstar” foreground artists at the American Museum of Natural History (AMNH) in NYC, Fredoin Jalayer.

20 Jalayer cactus I

Fredoin Jalayer circa 1950. Jalayer is seen here melting the wax mold off a plaster cast of a cactus. Jalayer probably innovated this brilliant molding/casting method that leaves the original spines embedded into the plaster cast creating a perfect replica of the original cactus.

While the Desert diorama was being constructed in the late 1950’s, Ralph Morrill knew the high quality work coming out of the AMNH and convinced the Peabody administration that his time was more valuable creating the taxidermy while details like the flowers should be contracted out to the NY artists. Jalayer was a great choice and his artistry is seen clearly in the Peabody’s cactus flowers. The details of the spiky flower base were sculpted in wax and embedded with actual spines. Jalayer created the internal anatomy of the flower with expertise; the stigma, style, anther and filaments are all accurate to this species. Unfortunately, the petals were made out of paper and wax. The paint used was not color-fast and the petals have drooped and have become brittle. This is exactly what we saw with the original paper and wax maple leaves in the Forest Margin diorama.

To create the new petals we started by following the methods used to make the replacement maple leaves for the Forest Margin (see my earlier blogs from July 2015 to October 2015). With the maple leaves, actual leaves were collected, photographed, and molded. In this case, we don’t have an actual flower to replicate. We have photos from the internet and Jalayer’s models to give us some guidance. To start, a simple prototype of a petal was sculpted in a very hard Chavant clay. The clay is so hard, that it needs to be warmed before it can be worked. A plaster mold was produced from the clay.


As with the maple leaves, we used 5 minute epoxy to cast. Instead of embedding a color photographic print on fabric into the epoxy as we did with the maple leaves, we used a pink-colored light gel filter to mimic the translucent color of the petals. The gel filter is a thin piece of colored acetate.  The color is highly saturated and, in this case, too bright for the color of the petals. It needed to be dulled down a bit and the epoxy, even when mixed with a dulling thickener, didn’t do this as well as I wanted. As a result a weird series of events that involved looking at a fly-tying catalog, watching candy making You Tube videos, and remembering fifteen years ago casting in colored elvax (basically hot glue in pellet form), I thought we should try hot glue rather than 5 minute epoxy as a material to embed the gel filter. I tried mixing alizarin crimson into elvax to see if I could get the color I wanted and forgo having to embed the gel filter. The oil color didn’t have the “pop” that the gel filter had, so that was shelved. I hadn’t tried embedding the gel filter using hot glue so I tried that. The hot glue dulls down the saturation of the gel filter enough that I felt I got what I wanted. There was one problem though, the hot glue sticks tenaciously to the plaster mold.  A silicone rubber mold is in process to accommodate the hot glue.


The plaster mold broke while trying to pull off the hot glue cast.  A square of the colored gel filter is on the left.


I think these will work well


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Weasel and Underwing into the Forest Margin Diorama

Phillip Krzeminski recently returned from a year-long intensive scientific illustration program through Cal State at Monterey Bay, CA. Not many applicants are accepted each year and only someone with a high level of proficiency can get in. Phillip is one of those rare individuals. Some of Phillip’s artwork is featured on his website at: 


Phillip stopped by my lab a couple of months ago and asked if he could help out doing something exhibit-related. I put Phillip to work on a model of a weasel for the Forest Margin diorama. I had removed the old, ratty, bug-eaten, taxidermied weasel from the diorama a while ago and Collin had scanned it for 3D printing. 


Phillip looked at the 3D print, noted all the additional artifacts of the printing process, and decided it would probably take less time to sculpt the model from scratch. Of course, that still took time to make sure all the measurements of bony landmarks were accurate. 01Once the armature was completed, a clay “gestural” model was sculpted. A plaster mold was made and a wax cast produced using the wood and wire armature. Phillip, started researching weasel musculature, of which he found only a few meagre references. There was one somewhat crude weasel reference online and he consulted the classic vertebrate anatomy guide: Miller’s Anatomy of the Dog. I also suggested he look at Antoine-Louis Barye, the French 19th century animal sculptor.


Barye combined anatomical accuracy with artistic power. He sometimes pushed the musculature to accentuate one area and he diminished other parts in the same sculpture to give the animal life. With the model muscled up, Phillip wondered whether he should add detail like claws that would barely be visible from the viewing window. I advised him not to worry about it, but he decided that he would invest the extra time to finish it off to that level. It turned out the claws made a big impact on the look of the finished model.03

Phillip painted the wax model in acrylic paint and we installed it into it’s place in the diorama to see how it would look in the actual diorama lighting. We found that it was reflecting light unnaturally, so we removed it again, took it back to the lab and added dry pigment to the surface of the paint to knock down the reflectivity. It was then placed into  position on the rock wall in the diorama.


Also, while going in and out of the same diorama, I removed an underwing moth with a broken wing. There are two pairs of underwing moths in the Forest Margin, one dark and the other light. This was the light-phase moth with open wings (the other light-phase one has closed wings)


Keeping good examples of insects/invertebrates in the dioramas is an ongoing problem. I am trying to use models whenever possible, for example, replacing organic specimens of scorpions and centipedes in the Desert diorama with 3D printed replicas.  (see previous blog entries) The underwing moths don’t fare well in the Forest Margin diorama. The dermestid beetle larvae love to eat them and I have to replace them every 2-3 years. In the Shoreline diorama, the label lists ants, hoverflies, earwigs, and a bumblebee that are supposed to be somewhere in the foreground, but I have never seen them (after studying the foreground this week, Nicole Palffy-Muhoray in Entomology found the two specimens of hoverflies on a beach pea.)

My mentor, Ralph Morrill told me that arsenic was painted on the surfaces of many insects, but the dermestids ate them anyway. It killed each dermestid that dined on them, but that only meant it took more dermestids to destroy an insect. I was asked recently by the entomologists if anything was ever sprayed on the insects to preserve them. I can’t remember Ralph or any other museum perparator ever mentioning it, but I would imagine, lacquer and other consolidants have been tried. That said, I suggested we try it anyway to see for ourselves. My assistant, Collin, took one of the new underwing specimens and sprayed Krylon Crystal Clear on it, soaking it thoroughly. Surprisingly, all four wings remained intact, but an unnatural glossiness was added to the surface and the upper wings, which started lighter than the lower ones, lost their lighter color and became indistinguishable from the lower ones. Collin tried to get it back to the previous lightness by adding light dry pigment to the upper wings . The dry pigment removed the sheen but didn’t restore the lighter color. Since the specimen wasn’t usable without the color difference, Collin tried painting the upper wings with acrylic paint to get the right balance of light and dark. Another surprise, it worked. We installed the lacquered, painted moth into the diorama.


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Live Model for Scorpion Painting


Stefan and his “pets”

Our live scorpions arrived today. My volunteer Stefan Hurlburt, works at a pet store and was able to order the exact species displayed in the diorama, Hadrurus arizonensis and Vaejovis spinigerus.


Hadrurus arizonensis in attack mode.


Vaejovis spinigerus, Striped-tailed scorpion (approx 1/3 the size of the Hadrurus)

Collin is painting them and we are talking about how to get the translucency seen in the real specimens when the 3D print is opaque blue! We noticed in the live specimen that the legs are smallest and lightest, the pincers are a bit bigger and slightly darker, the tail bigger still and darker. Collin has matched the colors so that when we put the model next to the live specimen, there is little difference. Collin is committed to pushing it as far as he can even though the models will not be seen close up.


Thursday, Dec 21:

Stefan came in to feed the scorpions this morning and he couldn’t find the smaller scorpion. They sometimes burrow into the dirt, but after going through it over and over, he still couldn’t find it. I joked that the big one probably ate him. Just then, Stefan looked into the other side with the larger scorpion and he said that’s exactly what happened. He found a small portion of the distal end of the tail with the stinger right next to the mouth of the larger scorpion. Stefan thinks that the smaller scorpion burrowed down to the plastic partition and nudged it up enough to slip into the other side. Not a good choice Mr. Vaejovis! Luckily Collin got good color notes on him yesterday.


What’s left of the Arizona Stripedtail scorpion and the painted 3D model


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New Developments in the Desert

The Desert Star flower harvesting/restoration in the Desert diorama has been productive. The tiny flowers were completely remodeled with new flowerettes and new (hairy) leaves. We finished about 200 flowers, with about 4 leaves per flower. IMG_0002IMG_0004Collin and I opened the diorama this morning and “planted” the flowers back into the foreground. The new flowers added a lot more color into the bland landscape. We also harvested a couple of cactus flowers that we will restore. IMG_0092

IMG_0091Secondly, we are getting great results with the 3D printing of the scorpions and centipede. Chelsea Graham has opened up her office at West Campus to us, specifically her Artec Space Spider scanner, for Collin to use for this project. Collin is learning the ins and outs of the scanner and we are both salivating to get one of our own for our lab. Dante Archangeli is helping us print them at CEID with the Objet printer. The results are amazing!


This is the smallest scorpion at 4cm


The next step is to paint them! I always like to use living specimens as color references if possible. It turns out, my volunteer Stefan Hurlburt can get us live scorpions-even ones of the exact species we are trying to replicate. Just this morning, I gave him the go-ahead to order a couple of each species!

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More on the Scorpions


Printed scorpion coated with Krylon spray paint. Excellent adherence

After the sodium hydroxide bath and power-washing at the CEID, the spray paint adhered beautifully to the printed scorpion and will provide a secure foundation for oil or acrylic paint. Note: Stratasys has a website that covers how to paint these prints: http://www.stratasys.com/solutions/finishing-processes/painting

The next step is to remove the actual specimens from the Desert diorama, which we did yesterday.

New specimens were replaced in the diorama in the mid-1990s. They are still in fairly good shape though there is some evidence of dermestid damage. Several of the distal segments on the centipede are gone. A couple of the scorpions are also missing distal segments and claws. Someone asked why we don’t try to get rid of the dermestids from the diorama and the answer is that it is difficult to find a pesticide that works, doesn’t degrade the display (or me!), and lasts more than six months. It isn’t feasible to open all the dioramas every year to keep a pesticide regimen active. So, we have decided to live with it. Old no-pest strips from the 1970’s are evidence that Ralph Morrill and Dave Parson’s made attempts to mitigate bug damage, but Ralph told me while he was still alive that it wasn’t worth his time to keep up with it either.

As for the preparation for the digital work, the over-riding concern I have is that the specimens are very fragile. I have been very careful, but I have already knocked off several of the legs on the centipede and I accidentally dropped the smallest scorpion. It’s tail and one of it’s legs broke off. The tail on the larger scorpion fell off without even being bumped!


Note the small tail-less scorpion and its missing leg. The larger scorpion’s tail also broke off, but was repaired and strengthened with an internal dowel.

I started using crazy glue to glue back legs, but I have found that the conservation-grade white glue works better. I quickly realized that our method of spraying white poster paint on the specimens won’t work on these fragile specimens, so I am reinforcing all the leg and antennae with white glue.


Reinforcing joints with white glue

It is not clear whether they will survive the ultrasonic water bath, so I may need to prepare myself for removing the poster paint manually with a brush and lightly soapy water.


Children’s poster paint applied. Specimens ready for scanning!

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Some Success with Small Specimens


Actual scorpion specimen on the left. Printed copy on the right.

Collin and I set up an appointment with Chelsea Graham at West Campus to try out her Artec scanner. We were told that this is the next level scanner up from the David scanner we already have and it might be the best for scanning something small like the scorpion. We took over two specimens to West Campus, a 9.5cm scorpion and an 11cm centipede. The scorpion was sprayed with white children’s poster paint first. The centipede was already a light color, so we thought we’d try it without the poster paint. It turned out that we didn’t have enough time to work on the centipede, but Chelsea was able to get a pretty good scan of the scorpion.

A pretty good scan is made up of many scans stitched together. Each scan was assessed before saved and then, if it made the grade, it was included. The scanning took several hours and some experimenting to get the scorpion in 3D. Chelsea worked further to clean up the scan file after we left and later sent us what appears to be the best scan we have been able to get to date. Collin immediately set to work sending the scan to the Taz printer. Again, we got the best print we have ever been able to get. Both filament printers (Taz 6 and Dremel) leaves a visible contour even at a high resolution print setting, which makes the prints hard to use without sanding or covering with wax or putting them into an acetone gas chamber (all clunky-especially with small things).img_1082.jpg

By coincidence I ran into Joe Zinter and Dante Archangeli from CEID (Yale Center for Engineering Innovation and Design) on my lunch break. This was on the very day that Collin pulled a couple of fair to middling prints from our filament printers. I asked Joe if he had a laser/resin printer at CEID. He said they didn’t have one, but that we should try their Fused Deposition Modeling Printer manufactured by ObJet. He told me the quality is as good as the laser/resin printers. Within an hour, I had the scan on a thumb drive over to CEID and they had it loaded and printing by the time I left. The scorpion print was scheduled to take 3 hours and 30 minutes, so I told him I would pick it up the next day.

I was back at CEID in the morning and the prints were done and still in the printer. Dante scraped it off the printing table and handed it to me. I wasn’t impressed!


Hot off the presses!

It looked like something you get from a schlocky halloween store. But Dante told me that most of what I was seeing was matrix that all comes off. You can literally pick it off with your fingernails. The cleaning appealed to my obsessive nature. I was supposed to get a display of taxidermied birds set up for this weekend’s Fiesta Latina celebration and I couldn’t stop picking away at the matrix and uncovering what appeared to be a very nice print. (I got the birds done later!)

I used ethanol to do the final cleaning, though I’m not sure it clears the matrix from the print. I went over and over the print removing more of the matrix each time. I finally got it as clean as I could and here’s the results. I think this print is ready to paint without any further work on my part.IMG_1079IMG_1080

I wanted to throw in one more issue that has come up with the ObJet print. The matrix is very difficult to remove completely. I spray painted the scorpion with Krylon matte white paint after going over it four times with a stainless steel dental pick. The paint adhered, but after it dried, I could remove it with a toothbrush. Dante and Joe from CEID said that sodium hydroxide (NaOH) was suggested as a cleaner by the company who sold the printer. First, I removed the spray paint with acetone, which seemed to have no effect on the printed plastic whatsoever, and took the paint-free scorpion back to CEID. Dante put it into a solution of NaOH. It was left there for about three hours. The solution seemed to loosen the remaining matrix, but it still felt greasy to the touch, almost like there was vaseline on the surface. Dante then gave it a high pressure power wash. After that, the print no longer felt greasy and I felt hopeful that I could paint it now. Unfortunately, I decided to check it with the dental pick again and here is the result:IMG_1087I’m going to spray it anyway and see how it works…Stay tuned. Also, Dante is contacting the company to see if they have any further suggestions for clearing the matrix.

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