apparently you can dissolve #potassium-silicate in water more easily than sodium-silicate #waterglass, which usually requires pressure cookers to dissolve it. Also apparently potassium-silicate binders make mortar #thixotropic!
on 02015-08-30#Konjac or konnyaku (glucomannan) at 0.5% in water makes a #thixotropic solution, and since it’s nonionic, it's not very pH-sensitive, stable down to pH 3.3. Konjac with xanthan gum in mildly acid food forms a thermoreversible gel up to about 40°, but under alkaline conditions, the gel is heat-stable (up to 200°!!) once it forms after cooling (even at 85°). At pH of 4 to 7, it doesn’t gel by itself, but does synergize with other gums.
on 02015-08-15an overview of #carrageenan. Apparently to gel it you heat it above 60° to dissolve it and then let it cool with potassium ions (for elastic gels) or calcium ions (for brittle gels). It seems like this might be better suited than alginate for #3D printing, since you could use a single nozzle that keeps the carrageenan solution hot to keep it from gelling. ι carrageenan gels made with calcium are #thixotropic, and used in toothpaste for this reason, as are κ carrageenan gels made with casein.
on 02015-08-15this lapsed Japanese patent from 2002 talks about making lime plaster (#slaked-lime) #materials sticky and #thixotropic by using 0.1%–5% #carrageenan (dry weight), which is apparently not as sticky as methylcellulose and won’t crack your plaster by absorbing water later. Some carrageenan molecules (κ and ι) gel with metal ions, while others don’t and are therefore more desirable for this. I'm surprised carrageenan will still gel in the insanely alkaline conditions found in lime plaster. It says you can use up to 4% or 5% (or sometimes as little as 2%) before it starts to shrink and crack as it dries. #patents
on 02015-08-15discussion of deflocculating #clay #materials by adding acid in order to make them less #thixotropic for #ceramics #slipcasting.
on 02015-08-15getting #ceramics glaze slurry #materials to be #thixotropic typically involves adding a little vinegar or Epsom salt (better for slurries that contain more #clay), but some ceramics processes require deflocculating your glaze slurry or slip to avoid thixotropy. For #slipcasting you normally just partially deflocculate the slip in order to let it remain a bit thixotropic.
on 02015-08-15