Do-it-yourself projects can lead a crafts person down the wrong path when dealing with either pressure tanks or vacuum chambers. Both of these have the potential too dramatically fail under pressure.
as far back as the early 1900's people have been killed or maimed with failures-Loooooooong lecture trimmed.
With permission from the owner here is a homemade vacuum chamber failure.
Glass Vacuum chamber at beginning of project
Blue is the color of the dye in use when vacuum chamber failed
Resulting eye injury from flying glass.
The chamber when it fails has air pressure pushing inwards.
The walls of the chamber very rapidly travel inwards, bounce out and decorates your shop with both the glass and the chamber contents.