Inventor/designer Bob Knetzger has 30 years experience making award-winning toys and other fun creations. Over the years, he’s contributed 20 articles to the pages of MAKE, but the very first was his Kitchen Floor Vacuum Former from MAKE Volume 11, so simple it’s evergreen. Want to make custom plastic 3D parts without a fancy 3D printer? Using your oven to melt the plastic and a household vacuum cleaner to supply the suction, Bob’s homemade vacuum former is the way to go. All you have to build is a simple wooden frame and a hollow box.

Bob waxes nostalgic in his intro:

My favorite childhood toy was the Mattel Vac-U-Form. The pungent smell of melting plastic filled my bedroom as I spent many hours molding little cars, bugs, and signs. The way the flat plastic changed shape by invisible vacuum power was magical and fun to watch!

Today, I use vacuum forming to make toy prototypes in my own shop. I usually use a professionally made vacuum former, but in a pinch I’ve used this ultra-cheap, homebrew rig with great results.

Large, commercial machines have built-in vacuum pumps, adjustable plastic-holding frames, overhead radiant heaters, and pneumatic platens. The Guerrilla Vacuum Former is much simpler.

Bob walks you through the build, available in its entirety on Make: Projects, then shows how to make the tiki mask pictured above, which also happens to make a great Jell-O mold. You still have two weeks left until Halloween, so this is the perfect build for this weekend.