Vacuum Former made from 4mm mdf.
Edited for better suction and few minor changes
Cut from 4mm MDF, vacuum hole is 44mm diameter.
Bolt together with M3 bolts, washers and nuts. Guide 'spikes' are 40mm long M3 bolts, through the whole assembly. (see 'irl' pic)
The black plates are rubber, used to make a nice seal, but could use rubber band technique.