Sunday, May 15, 2011

Homemade Vacuum Forming Machine

A machine for forming vacuums?  No.  This is a machine that uses vacuum to form things out of sheets of plastic.  It's based very loosely on the plans and description of the same machine in Thurston James' book the Prop Maker's Molding & Casting Handbook with a bit more guidance from and a host of my own refinements.
 Most hobbyists who build their own vacforming machine make the oven out of calcium silicate or hardibacker board.  I decided I needed to make mine out of steel.  Unlike other people who make things out of steel, I have very limited metalworking skills.  More specifically, my metalworking qualification level is what professionals refer to as "dangerous." 

To mitigate the potential danger, I enlisted the help of my uncle Mike again.  Here's a shot of him demonstrating his proficiency at the metal shear:

Metal sheer

This is me braking things:
braking things
I wasn't quite as angry as I looked.

Once I had the inner and outer boxes of the oven, we coated the inside with high-heat paint:
Forming oven painting

While waiting for the paint to dry, we flipped the inner box over and I laid out the pattern for the heating elements:
Forming oven layout

Meanwhile, Matt did the calculations for the lengths of the heating elements:
Forming oven calculations

Once we were happy with the plan, we mounted insulated posts into the oven for the mounting of the nichrome wire heating elements:
Forming Oven posts
The nichrome wire and the ceramic posts came from  Fortunately, I ordered way too much of both.

The initial plan was to break the whole area up into four separate heating elements wired in parallel and running on 110V.  It turned out that our initial circuit design didn't quite get hot enough to serve our purposes before it tripped the breaker and the lights went out.  It turns out that it's really hard to vacuform without electricity.  You have to suck a lot harder.

So the next order of business was to convert our four 110V heating elements into ten 240V heating elements:
Oven Wiring

After a quick test for hotness (wherein hotness was achieved) it was time to add some insulation:
Oven Insulation

Fully assembled, the oven was huge:
Huge oven

It was also smoking hot:
Smoking oven

After a few minutes of cooking, the smoking ceased.  It seems the smoke was just from burning off the dust that had settled on the top of the inner box of the oven.  In the shot above you can see one of the six orange C-clamps that hold the two halves of the frame together with a sheet of .040" ABS plastic in between.

Here you can see the first forms on the vacuum table:
Panel Forming Bucks

Here's the whole machine set up and ready for forming:
Vacforming setup

Finally, here's one of the first panels formed with a quick and dirty test paintjob:
Formed Panel

Great success.

Now I can make drop ceiling panels and costume parts and helmet faceshields and coffee cup lids and card pack blisters.  All kinds of fun can be had when you've got something that can suck for profit...



  1. I had been considering buying a machine from
    Now I think rather than spending thousands of dollars, I may consider making it myself (or calling you)

  2. Nice job, but I would still buy a machine from

  3. Perhaps you missed the point then. Mine cost a couple of days and a few hundred dollars.

    Commercially made machines capable of forming a 24" x 48" sheet start at around $8k. Given the budget I had at the time, it made more sense to spend a bit of time rather than a lot of money.

    When money permits, I will be upgrading to a professional machine. For now, this baby works just fine.

    1. No, the point missed him. I'd say the vacuum in his head caused it.

  4. This is brilliant! Can I ask, when you're heating the sheet of plastic, is it clamped up where those little orange G-clamps are? Do you lower it manually to the vacuum table? Do you need six arms to do that? Cheers!

  5. Planning out a similar project. Can you tell me how many watts your heater draws now at 240v? I'd like to be able to form slightly larger than yours I think i need 24 x 60 if i remember correctly.

  6. This work need hats off, Brilliant !! Vacuum thermoforming is a well known manufacturing process where a plastic sheet is heated to a temperature that makes it moldable.