My Polymer Press output pipe ended up in line with my Natural Gas Generator's output line, and the steady stream of 22.5g packets of Carbon Dioxide seem to be preventing the Polymer Press from plasticizing, pursuant to proper passing of previous precipitate. This was fixed a while back for other buildings (Latrine and Sink, as I recall). Perhaps parity pending possible Polymer Press patch?
I'll show myself out now.
Pass a steady stream of small carbon dioxide packets through an in-line Polymer Press output.