I think it's a longshot that I ever get my hands on a blow-molding machine like those we see up there. The prices for even used machines are a little out of my school budget. I can certainly afford the preforms, though.
I've tried warming up the preforms in boiling water, but that appears not to be hot enough to allow the plastic to be inflated.
Luckily, Ed Escudero, one of our ASM master teachers and a fellow Cincinnatian, recently came up with a way that we can model the injection molding of the preforms in the classroom.
Ed uses soda bottle caps with tire stems glued through them (available from Flinn Scientific individually or in bulk) and a bicycle pump to generate pressure inside the bottle. He wraps the bottle in a flameless ration heater (FRH) (available from military surplus stores or from ZestoTherm here in Cincinnati - developed at the University of Cincinnati, by the way - or simply given out to ASM camp attendees every summer) with a corner cut off to allow water to be poured in but hopefully not to pour back out. The FRH is held horizontal long enough to allow water to thoroughly soak the magnesium powder before being secured by rubber bands around the preform.
Once the preform is hot enough - something that takes a couple of minutes, the bicycle pump is pumped to increase the internal pressure and inflate the 'bottle'. The procedure doesn't produce anything really resembling a traditional 2L bottle, but it works pretty well as a proof of concept for the students.
Check out Ed's set-up below...
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