While we never received a response received a delayed response to our request to sample the one carbon company’s graphite in ethanol solution, I was able to find powdered graphite at the local art store and we mixed it with water and ethanol in different bottles.
Depositing the substance out of a pipette onto an ABS substrate, the ethanol spread rather easily. Depositing strips of mostly uniform width was possible, but additional material added while the first layer was still wet made the strip wider. In order to achieve thickness with the ethanol, several passes or a channel in which to deposit the solution will probably be necessary. In contrast to the ethanol, the water droplets balled up and it was easy to deposit a thick blob. However, it was very difficult to give the blob much length as once a droplet touched the main blob, it was pulled in.
I ran across some notes about surface tension and printing, but in the end in may just be easiest to first construct a channel in which to deposit the solution with graphite powder. It is important to note that the ethanol needs much less time (around 15 minutes) to dry and so is probably the preferred solvent.
Sticking multimeter probes on top of the graphite deposited with ethanol, I measured resistivity on the order of 1000 Ohms. Pressing the probes on top of the dry powder rubbed the powder away in the case of the thin ethanol-deposited strip. In the case of the thick, water-deposited blob, the pressure cracked off pieces, and I wasn’t able to get a reading in time. I’ll conduct a next round of testing, which will hopefully yield more trustworthy numbers from a better designed test, and will report back next week.
Forays Into Desktop Fabrication 