Have you ever seen an aircraft that you would really like to model, but cannot find a canopy suitable for it. This has probably been the cause of many modelling projects never getting past the proverbial sketch on the back of an envelope. I have come across this problem many times in the last few years. This problem can be solved without spending all the housekeeping money.
Vacuum forming is quite simple.
The illustrations show how my machine was constructed. The size of the unit is entirely up to you. As you can see it is a simple wooden box divided into two sections, one for the heating element and the other for the vacuum. The side of the box which has the heating elements in it must be protected from the heat that will be generated. I used thin aluminium.