Step 2: Bill of materials

Picture of Bill of materials
This instructable requires a few custom materials and tools. The lab where I made the sensors already had most of the materials/tools available or they were custom-made there, so I apologize for not being able to direct you to specific suppliers/part #. If you try the instructable, please post where you got your materials from!

Part: Nylamid spacer (Diam: 13mm, Thick: 2mm)
Supplier: Custom-machined
Qty: 1 per sensor (reusable)

Part: 20A Shore RTV Silicone
Qty: ~2g per sensor

Part: 65A Shore RTV Silicone
Qty: <1g per sensor

Part: Acrylic (transparent plastic) board with circular indentations
Specs: 25mm minimum width and length
Centered indentation depth: 0.4 - 0.6mm
Centered indentation diameter: 4 - 6mm
Additional indentations at a minimum 30mm distance in any direction
Supplier: Custom-machined
Qty: 1

Other: Assorted modeling hand tools, precision scale, metal roller, silicone solvent.

NOTE: You can get the silicone and solvent from Nusil Technology. The modeling tools, you can probably find in a good art supplies store.

Alliraph7 years ago
Hello Operon, I read about the selection of silicone hardness from your thesis. Is there any alternative if I can't get the silicone with hardness of 20A and 65A? As in one of your experiments, you concluded that "The softest or the hardest silicone types (shores 20A and 65A) are recommended for MMG measurement, as they exhibited the least variability during the tests." I wonder if a difference of ±5A would affect the measurement much. What do you think? Did you use any mold while embedding the components? Packing the silicone to the sensors like you described gives me an idea that the viscosity of the silicone is very high like modeling putty. I assume the silicone you used is for potting and encapsulation purpose, which generally has low viscosity. Is it not? As I know most of the silicone encapsulation use pouring method which requires mold. By the way, thank you so much for sharing this instructable. That's really a cool stuff. I wish I'll be able to build one.