I haven’t forgotten about this blog. It’s actually been on my mind for some time. I’ve just been really busy. School has started and I’m overwhelmed at the moment. I’m looking forward to the near future when things settle down a bit and I can get back to focusing on this research.
I’ve been working on several fronts. With regards to testing powder behavior, I’ve built a system for measuring friction within the powder. This should allow me to predict how materials will behave in small batches before committing to larger amounts for the machine. I’ve also started using a new dry mixing system (it’s actually resurrected from the engineering department’s grave). I’ll document both of these as time permits. Finally, I’m still actively searching for a better way to screen material.
In the meantime, I did get some promising results. I re-ran some batches of ceramic powder through our spray drier equipment. In my original attempt, only 22.3% of the material I started off with in slip form ended up being usable after spray drying (where usable = passing through a 200 mesh screen). The vast majority was simply too large.
For this second batch, Hyojin suggested dropping the PEG down to 0.5% He also suggested making a volume suspension of 20%.
This worked out to be 52g dry / 80g water.
In batch terms…