Monday, October 29, 2012

Crash Test Dummy

I have been meaning to post this for a while as this fabrication happened back in September. I was asked to remake and alter a crash test dummy head and hands to resemble those from a vintage 1950's dummy. The client was interested in the look of the vintage dummy but needed something that would withstand extreme impact. 

There were many factors to consider other than just a cosmetic remake of a head and hands. First of all the parts that I would be making needed to be able to attach to a rented crash test dummy body. Also, the dummy would be impacting at 90 mph and the parts would need to stay together during the impact. In addition I needed to change the skin color of the dummy. The new ones were to be dark brown red instead of the more yellow caucasian flesh color of the original vintage dummy.

I needed strong and durable materials that I would be able to tint.

To start, I made a "life cast" of the original dummy head. Then I made a cast in clay using Chavant NSP, (melted and brushed in and reinforced with burlap). I was then able to resculpt the mouth in an open position to match that of the vintage dummy.

A new mold of the head was then made out of silicone rubber and Plasti Paste. To cast the head I decided to use Task 16, a urethane rubber by Smooth-On.

The Task 16 was tinted and roto-cast by hand inside the head to a thickness of about a half an inch. I then used Flex Foam V to fill the rest of the head making sure that the foam didn't fill the neck. The foam added structural support without adding too much weight to the final product. I then filled the neck area with a little more Task 16 and let that cure.

The original head attached to the dummy body via a bolted on metal bracket. I needed to make sure that the new head would be able to attach in the same way.

I drilled out large holes to inset three standoffs--fittings that thread from the inside (purchased from mc master carr) into the cast head. Using a cast of the bracket (that I had molded earlier and cast in Smooth Cast 300) I attached the standoffs with machine screws and placed them in the drilled holes. I filled the holes with a little Task and once that cured I took the bracket off and added more Task around the top of the fittings.

The hands were much simpler because I did not have to alter them. They just needed to match the skin tone of the newly cast head. Silicone and Plasti Paste two part molds were made of each hand. They were then cast in solid Task 16 rubber tinted with with same Flesh colored So Strong pigment.

Once the Task cured rubber I had to cut away and drill out of the wrist area so it could attach with the existing hardware of the crash test dummy.

After everything had been cast my client decided that it needed ears (after my sculpture, sans ears was approved. The 1950's version had ears, the new versions do not.) So I did a quick sculpt of simple ears, molded them with body double, and cast in them in tinted Task 16. The ears attached to the head with Task 16.

Next, the head just needed a little paint to match the vintage version. Pupils, eyebrows and some hair.

Just a few days later the dummy was shot in black and white with a high speed camera, and looked (and worked) perfectly.

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