Instructables Labs' Vacuum Former (STEP VERSION)




About: "Almost Toast"

Greeting Instructabrarians!

So here at Instructables Labs we have several truly impressive machines.  We have several Epilog laser cutters which can cut through most plastic and wood material and etch almost any shape (Including cylindrical objects!).  And we also have a couple of truly astounding, expensive, 3D Printers with an extremely high DPI resolution and can create a real copy of any digital computer model. 

BUT, as strange as this may sound, for me these two just weren't enough.  Sure the Laser Cutter is impressive at raster etching and vector cutting but its limited by the flatness of its material.  And the 3D printer, while awesome, does tend to rack up in the price range as well as take up to several hours to finish.  For my interest in rapid prototyping I wanted something fast, accurate and able to create near perfect molds within seconds.

That's why, after nearly a month of development, I successfully created Instructables Lab's first Vacuum Former, Office Edition.

Editor's Note: I'm reposting this as a STEP BY STEP after getting so many requests.

Step 1: About Vacuum Forming


For those of you who don't know what vacuum forming is, there's a really nice description on  The phsyics is really simple: take a piece of sheet plastic, stretch it across a rectangular frame, and heat it up to a boiling degree.  Then, using either a perforated board or a single sheet with a hole connected to a high suction vacuum, a desired object is placed on top.  When the plastic is heated to a malleable degree, the plastic is placed on top of the perf board/ board with vacuum.  Vacuum turns on, plastic forms around the object, and instant mold!

Step 2: Parts and Materials

Now, I know there are some truly amazing vacuum formers on the site, but for the purposes of this project and to show how truly easy Vacuum forming is, I decided to build the simplest set up possible.


To build Instructables' NEW vacuum former, all you need are these common household objects
  1. Tin Tray
  2. Shop-Vac Vacuum Cleaner (the more industrial strength, the better)
  3. Strong wooden, rectangular frame 
  4. Large oven
  5. Cardboard Box
  6. Painter's Tape
  7. PVC Pipe connector (or some kind of connector piece that attaches to vacuum nozzle) 


Vacuum Forming is NOT difficult.  The only thing that takes a while to understand is knowing how long to leave the plastic in the oven for and what temperature to set it at.

Take a thin piece of sheet plastic.  Anything larger than 1/2'' is too large and will not be malleable enough to mold using a domestic shop vac.  For best uses, I suggest polystyrene sheet (from Tap Plastics) 1/8'' or any thin flexible clear plastic sheet.

Step 4: Step 2: Attach Plastic to Frame

Choose the appropriate Wooden Frame that your object can fit easily into, while still providing enough space for vacuum suction.  I ended up creating three different kinds: a modest 4'' by 6'' photo frame, a larger 7.5'' by 9'' frame, and a very large 10'' by 12'' rectangular frame.

Cut an appropriate sheet from your sheet plastic so it fits over the frame.  Then using the blue painter's tape, tape down the edges of the sheet to the frame.  You might also want to staple the frame to the plastic, for extremely large objects.

Step 5: STEP 4: Attach Object to Tray

Using a bit of painter's tape, take your desired object and then tape it to the top of the hole on your tray.  Make sure there is enough of a gap to provide suction.

Step 6: STEP 5: Preheat Oven

Preheat the oven to 500 Degrees.  Nothing less.

Step 7: STEP 6: Most Important Step

Most Important Step: Once you have the oven set to a boiling degree, put in your wooden frame with sheet plastic facing up.  Depending on the type of plastic, you may want to lower/rise the temperature at this point.  The plastic should already start to deform. Make sure that the plastic on the frame does not touch the bottom of the oven.  This entire process happens literally in seconds.

EDITOR's NOTE: I know I'm using an iPhone instead of the head in this step.  That's because I ended up posting this photo afterwards.

Step 8: STEP 7: Remove Plastic From Frame

Very quickly take out the frame, lay the plastic face down on top of your object.  Turn on vacuum cleaner and then create mold!

Optional Step: If plastic has not formed nicely around your object, use a Heat Gun and melt the plastic a bit more so it deform to a more accurate shape.  Turn on vacuum.

Once plastic has dried, carefully remove plastic from object.

Step 9: Conclusion

And that's it!  Vacuum forming is literally the easiest process in the world, once you master the technique.

Vacuum forming is a process I have been interested in a very long time.  The appeal of creating an exact instant mold without having to spend several dollars on expensive casting or resin, was something I was very dedicated to pursue. 

Even though I have a bunch of projects lined up using the new vacuum former, I really built this with the hope that the entire instructables team might find a use for it.  DIY Snowglobes, Instant Robot Heads, Waterproof Enclosures, the possibilities are endless!

Well, hope this helped.  Go make some cheap plastic crap!


PS Tap apparently sells both recycled and BPA safe plastic.  Or so I've been told.

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    18 Discussions


    Reply 5 years ago on Introduction

    You can use a heat gun if you aren't forming large objects. There are a few instructables that use this setup.


    Reply 6 years ago on Introduction

    I wouldn't advise using a microwave, for its main difference than an oven. Rather than raising the temperature, microwaves would bombard the plastic with energy and studies have shown that this can release poisonous gasses as a result. Secondly, in order to get the plastic to deform, you need to have the temperature at least above 300 F and since microwaves don't cook by raising temperatures, I don't think it deform the plastic as required.

    If you don't have an oven, it's going to be tough since you need something with a wide enough area to heat the plastic sheet uniformly. Your best guess is probably a Mojave Patio Heater, except your set up will look different. Use this a reference



    6 years ago on Introduction

    Nice work on this! How do you think the technique would work with paper that has been steamed slightly? Im trying to mould paper

    Robot Lover

    6 years ago on Introduction

    My dad has made many vacuum forming machines. He has a lot of experience with this type of thing. He has made frames that clamp around the edge of the plastic so you don't have to staple it like you. I really recommend it!


    6 years ago on Step 8

    What would have been really cool at this point is to see the plastic, still on the frame, and the frame in the pan with the molded item, before the frame was taken out of the pan and the plastic was taken off the frame.

    I've wanted to vacuform something for a while now (it all started with a stormtrooper armor, but I think I've moved on to more practical applications by now). Anyway, is the frame supposed to fit inside the tin tray, or not? Seeing how you made different sizes of frames I do not think so, but that would mean that the plastic needs to stretch from frame to the base of the tray, so larger models, i.e. those filling the tray to a larger extend, would be harder to form, possibly overstretching the plastic near the edges... Does this make sense?

    I'll try this anyway, thanks!


    Reply 6 years ago on Introduction

    Fairly high, depending on your object you want formed. I havent posted it yet, but I created a giant bust of someone's head and vacuum formed if extremely accurately.


    6 years ago on Introduction

    500 Fahrenheit degrees?

    I am thinking to use a heat gun to heat up the plastic sheet. What do you say about it? I would make this while the vacuum cleaner is working.

    Thanks for sharing this method.

    1 reply

    Reply 6 years ago on Introduction

    Heat gun definitely works, but only for small touch up parts. It can't heat up the plastic uniformly enough to provide for an accurate vacuum seal.

    But depending on the size of your item formed, it might work if it's smaller than an iPhone.