Autumn and I took the train down to the American Museum of Natural History (AMNH) to meet with their vacuform specialist, Beck Meah. We brought a couple of our printed vacuform leaves to show her what we are doing. We met her on the fifth floor of the Exhibition Department where the vacuform machine is located and got to “talk shop” for about an hour. The AMNH’s vacuform machine has a defective vacuum pump and they have rigged it up temporarily with a regular shop vac. Surprisingly, they seem to be getting good results with it! They use clear Vivak and sometimes a thin white (opaque) styrene instead of acetate or PETG. Beck said they bought a large amount of the Vivak years ago. She gave me a sample to try back at the Peabody. I put a vernier caliper on it and it is thinner by half! of what I am using. The PETG I use is .020” and the Vivak is .010”. She said that they are looking for a good glue to adhere the leaves to the wires, which is a problem I have, as well. I use B-72 and the results are less than satisfactory. Beck said they sometimes drill two small holes in the vein and snake the wire up and through the two holes to hold it mechanically rather than depend on the glue. She also said that in some of the dioramas the preparators would wire the leaves on top of the leaf if it was going to be seen from below to help hide the wire. We will use that advice when we make the maple leaves for Forest Margin diorama for that very reason. They will be seen from below. Beck uses extrinsic painting on the leaves and says that she can get an acceptable translucency by keeping the paint application light. I believe her because Tomy Newberry and Gary Hoyle, two preparators I have great respect for, both said the same thing to me. That said, I have found that any paint on the surface reduces the translucency and I am sure the old-timers knew this and struggled with it as well. I walked through the African biodiversity exhibit, which opened ten years ago or so to assess some of the more recent leaf work. I found the leaves to be mostly opaque which therefore gives them (now that I have been mentored by Ray deLucia) an unsatisfactory plasticky look. The form was good because they were vacuformed, but the realism was lost to some extent because of the opacity.
At the AMNH, they make plants by soldering together brass branches and adhering the leaves afterwards. I learned to make plants by making the leaves and gluing on the petiole, or leaf stems, first and then wiring them together afterwards using shrink tubing and epoxy glue, building the plant from the top down, adding more leaves and branches as I go down. With this method, I get rather lumpy branches that need attention to get them to look realiastic. This other way might save time. Beck said that there is a soldering tool sold at Micro Mark that can solder small brass wires to thicker stems with just a tiny bit of solder. That sounds like a useful tool to have around. This is why I love to talk to other museum preparators!
Autumn and I left Beck and walked down to the Olympic Rainforest diorama to look at the leaves done in the early 1950s by the legendary foreground preparators, George Petersen, Fred Jalayer, and Tomy Newberry. We were blown away at the attention to detail, the translucency, and the realism everywhere we looked. This level of quality probably can’t be recreated today. George Petersen made leaves for his whole career at the AMNH. Forty years of honing one’s skills just on leafmaking is hard to match by us generalists!