Make Architecture



6 Give me a hand with this one


This week I decided to cast my hand. The end result is a light fixture – the hand mold holds an incandescent light socket.


For this you will need:

(3) Smooth-On OOMOO 25 (tin-cure silicone rubber), 2.9lbs. pack

(1) Activa Permastone Casting Compound, 28oz. pack

1/8″ Foam core

hot glue gun

scotch tape


vaseline/petroleum jelly

(2) mixing buckets

Step 1: The Mold

Cut and glue foam core mold in approximate size of hand. Minimize excess volume around hand in order to conserve Oomoo compound. Tape inside and outside seams of mold to avoid seepage.

NB: For ease of hand extraction, coat arm in vaseline or similar. However, loss of detail will occur. Finest detail occurred where I had not coated my hand in vaseline (ie fingers). Lowest resolution occurred where vasoline was thickest (ie wrist).

In order to make this a light fixture, I held an incandescent light socket in my hand while the Oomoo 25 was poured.

Step 2: Mold Pouring/Arm Extraction

Hand was left in mold for approximately 1.25 hours. Once the Oomoo 25 begins to congeal, it naturally begins to peel off of skin.  The Oomoo 25 compound does not heat up when setting, so there is no discomfort. The box does advise to wash skin “thoroughly with soap and water” in the event of skin contact.

Eventually, I was able to simply pull my hand out of the mold without destroying or otherwise cutting it. It was tight, but the Oomoo 25 is flexible enough to deform. Vasoline on skin also facilitates extraction.

Step 3: The Positive

The Activa Permastone package stipulates (1) part water for every (3) parts Activa compound. I found that this is not enough water – the casting material began to set almost immediately upon mixing. I was still able to pour it, but it was alarmingly viscous. A single 28oz. package of the Permastone was exactly enough to fill the mold volume.

Step 4:  Excavation

The mold must be destroyed in order to retrieve the hand. First I removed the foam core shell. Then, I began cutting/tearing away the Oomoo mold, slowly revealing the hand. Toward the end of this process, tweezers and needle point instruments were useful for removing the Oomoo from tight spaces. I had to repurchase an incandescent light socket because the Oomoo 25 had completely invaded the first one.


In several spots, trapped air bubbles were unable to escape due to the position of my fingers. It’s the same principle by which toilets flush – a water trap prevents air movement in either direction. This could have been remediated with sprue (ie a straw embedded in the mold) that would have allowed the bubbles to escape.

The best resolution can be found in places where there is no vaseline. I think I still would have been able to extract my hand without any vaseline coating.


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Instructor: Nick Gelpi TA: Skylar Tibbits TA: Varvara Toulkeridou
Class Times, Monday, 1-4pm - room 5-216
4.184 is an intensive introduction to methods of making explored through a wide range of brief but focused 1-week exercises. We'll engage the real and leave behind representation in the focused context of this class gaining skills for utilizing a range of fabrication machines and technologies from lasercutting, waterjet, 3D printing, welding, formworking-molding, casting, gears, joints and composites.
In this workshop we'll constrain ourselves to the territory of the 1:1. Students will represent architectural constructions at full scale and develop a more intimate relationship with technology by engaging the tools and techniques that empower us. We will gain access to the most cutting edge machines and technologies in the MARS lab at the Center for Bits and Atoms.
The second layer of information for this course will be to look at a series of case studies in which construction methods and technologies have played a dominant role in the design process .
Over the past 20 years, architects have focused on the technology of representation to create new ideas of what architecture could be. Looking back today, much of that research failed to substantially change the way we design buildings by focusing on apriori formal configurations. This class makes the contention that this failure comes from a lack of considerations of the potentials within fabrication knowledge. We look to the future of what building might become, given the expanded palette of personalize-able technologies available to us as architects. Students will participate in curious technological and material investigations, to discover the potentials, known and unknown, for these various technologies.
The sub-disciplines of what's drawn and what's built have been compartmentalized and disassociated as the representational tools of architecture have distanced themselves from the techniques of making. At the same time the technologies for “making” in architecture have provided us with new possibilities for reinventing how we translate into reality, the immaterial representations of architecture.


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