My Vacuum Former





Introduction: My Vacuum Former

About: My 30's have become a sort of renaissance for my tinkering and building.

Before I set out to build my own vacuum former I did alot of research on various DIY sites.  I found alot of helpful tips and designs.  Ultimately I settled on components from several different designs.  My design is by no means perfect, but it gets the job done, and was fairly cheap to build.  It is capable of forming a piece 33" x 22".

Step 1: Basic Box

I started with a basic five sided wood box out of half inch particle board.  This will be the infrared "oven".  24 inches deep, 35 inches long, 24 inches wide.  Thats pretty straight forward.

Step 2: Heat Source (also Keeps Your French Fries Warm)

As I said, I researched many different designs before I started and found that I preferred the infrared lamp as my heat source because, well frankly, I thought I'd burn my house down if I tried to build my own heating element.  I even considered buying three electric pancake griddles, bolting them side by side into a box, and placing that over the plastic sheet.  I tried it with one griddle and it worked pretty well, though my wife was not pleased with me disappearing into the garage with it.

I used a total of ten infrared heat lamps that you can purchase at any hardware store.  There are four 250 watt bulbs, six 125 watt bulbs, and one 1200 watt patio heater.  I had the patio heater already so i incorporated it, but i'm sure I could have used 4 more 250 watt bulbs in its place.  This gives me a total of nearly 3000 watts of heating.

The bulbs are mounted with ten porcelin standard 120 volt, 600 watt light fixtures.  The kind you find mounted on a rafter in your attic, or in a garage, or basement.  They do not have a pull string or switch built into them.

When figuring the placement of the bulbs I had to take into account the thickness of the insulated panels, which I will explain later.

Step 3: Wiring (not My Strong Suit)

I'll be upfront...this part worried me the most.  I would have liked to have used junction boxes and romex for all the wiring but I decided to throw caution to the wind when the budget ran thin.  40 feet of wiring cost $3.00 versus all the romex and junction boxes costing $60.00.  I did however oversize the wiring, and use a whole roll of electrical tape on each wire nut to put my mind at ease.  I connected the wiring in three circuits to avoid tripping breakers in my house.  One circuit is the patio heater alone.  The second circuit is the four 250 watt bulbs in the middle.  The third circuit is the six 125 watt bulbs on the outside.  Each circuit has its own cord.  This configuration was designed to minimize load on any one breaker in my house.  I can plug the whole thing into my garage circuit, but I don't simply because I'm paranoid that the builders of my tract house did a crappy job with the wiring.  This configuration has the added benefit of allowing me to control the heat required for different thicknesses and material types.  For thiner materials I can just use the patio heater, or the patio heater and the four 250 watt bulbs.  For thicker material I can turn on the six 150 watt bulbs.

I mounted the whole thing on the bottom of an old janitors cart I had.  The bottom shelf serves as a cavity for the wiring to be stored and protected.

Step 4: Insulated Panels

Obviously particle board and enough heat to cook a turkey in about an hour aren't a good combination so I thought I should insulate the heat box.  I found that the insulated panels would serve several purposes.  First, they keep the particle board from getting too hot.  Second, because the plastic sheet serves as a kind of cap for the heat chamber, the insulated panels help hold the heat under the plastic rather then letting it disipate into the air.  Third, the panels are made of galvanized steel which help diffuse the infrared radiation as it moves up towards the plastic.  (I assure you I only made half of that up).

The insulated panels are 24 gauge sheet metal panels.  They are composed of two square "pans" that have a one inch blanket of insulation between them.  The pans were then rivetted together.  One of the pans has a longer edge at the top where I formed a channle to hook onto the wood side.  I am a sheet metal worker by trade so I have made similar panels before, and I have easy access to the materials for free.  If I didn't have access to the metal I could have just used the insulated blanket, which had one foil side, and foil taped it directly to the wood.  Since the bottom of the box is not exposed to as much heat I settled for just using the insulation material to cover it.  The panels have worked remarkably well.  There is absolutely no noticeable rise in temperature on the outside of the box or the internal surface of the wood, even though the inside reaches 450 degrees.

Step 5: Vacuum Table

The vaccum table consists of 3 layers of 3/4" particle board.  The top layer has roughly 500 3/16" holes drilled an inch apart on center.  There is a two inch boarder of foam rubber tape to give a good air tight seal between the frame and the vacuum table.  The second layer is just a frame with a two inch boarder which will provide a void between the top and bottom layer.  The third layer is a solid board with a single 1 1/2" hole cut into it for the vacuum hose to be attached.

I inserted a 1 1/2" male thread to 1 1/2" female slip pvc fitting into the hole on the the bottom of the vacuum table and glued it in place with a strong epoxy.  The 1 1/2" fitting was a perfect fit for my vacuum.  The electrical tape in the picture was just a cheap way to make the connection in a non permanent manner.

Step 6: Plastic Holding Frame

Most instructions I found for building frames used some sort of aluminum window frame.  With my design, I went with a wood frame with several bolts holding the two halves together.  I did this because the wood doesnt transfer much heat to my hands when I pick up the frame to place it on the vacuum table, and I already had the wood laying around.

Finally, the hot box, the vacuum table and the frame are stackable for easy storage, and the whole thing rolls right into an out of the way corner of my garage.



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    The plastic holding frame. Screw a couple of handles to it...! No burned fingers then....



    Hey Nick - This unit looks great and apparently works well. I like that you split the current load between all that stuff, and that you don't have to use an oven.

    I have a question - I am thinking about vacuum forming a cover for a 10" clock (this would be the clear lens on a clock that protects the clock hands, and clock body, etc). I don't know exactly what this component is called, but what I wanted to do is convert a commercial type of ceiling light fixture into a neonesque clock, by adding a clock movement, some coloured flex led/neon tube to the inside, and a clear lens that would protect it all.

    The piece I want to form would be shaped kinda like a straight sided bowl, 10" in dia at the bottom, 9-5/8" dia at the top, 5" deep, as measured if it were a bowl turned upside down. Anyway, to do this, my question is - would the form need to have holes drilled in it also ? Or would a solid wood form be ok to use ? Could I use the actual fixture itself as a form to vacuum over ? Thanks in advance - t

    1 reply

    I am not an expert but I've heard that forming objects with perfectly vertical surfaces is difficult. I would suggest making sure the plastic is nice and hot before sucking it down and maybe having a heat gun ready incase any creases form. Drilling holes is maybe a good idea however i wouldn't go too big. I tried that on a few pieces and ended up with tiny but noticeable dimples. You could use the fixture if it is strong enough to withstand the heat and vacuum pressure. Good Luck!

    Very nice job you've done on this.I'm planning to build one as well in the near future. I have a 240v 3000w temperature controller and 2" 1200 degree insulation sitting on a shelf already waiting. I have two questions. 1. How thick of material have you formed with this? 2. Could you have made the dimensions bigger with your current heat supply? I am aiming for 24 x 60 with 1/8" ABS but not sure if 3000w will be enough. What's your opinion?

    1 reply

    Thank you. I have only formed 3/32 polystyrene so far, but the heat source is capable of 450 degrees given enough time. So in theory, as long as my vacuum could handle it, I think 3/16 ABS would be the max for mine. I think if I had gone bigger I would have needed more lamps. The biggest problem I have is the edges of the plastic not heating up as fast as the middle.

    I just wanna know what one does with a vacuum former. What is its purpose?

    5 replies

    I had the same question - what the heck is a vacuum former, and why should I have one?

    Now that I know, I'm looking for a project that needs one.

    "It is better to have a tool and not need it, than it is to need a tool and not have it." Yes, I identify with that.

    The original intent was to make custom cases for the delicate instruments I use for my job. I was going to form them out of ABS plastic. The piece shown in this instructable (the two triangle shapes in the plastic sheet) are forms for casting foam or resin ears for a costume for my son. I may make some custom storm trooper armor for my brother and his 6 year old for halloween.

    One of my favorite tinkerer's quotes is "It is better to have a tool and not need it, than it is to need a tool and not have it."

    I have that same quote for my crochet hooks, knitting needles, tatting needles and shuttles. Therefore, I don't think I have less than 3 of each size of anything. And, don't get me to talking about my yarn stash. LOL

    Thanks for the info on the vacuum former. I always appreciate being educated; especially if done in a kind and humerus way.

    Also, just search YouTube for "Vacuum former" - you'll see all sorts of neat articles!

    s/articles/videos >.<

    A demo would be nice, maybe link to a youtube of you using this to give us a better idea of exactly how it works for those noobs of us who would like to learn to do such things.

    Well Done! .. Especially the 500 holes ☺

    I would have liked to see the articles that the plastic mould (Oz spelling ☺) was formed from.
    Also some other things you may have done with these types of units.

    I use to work next door to an importer back in 1972, they would import cheap stuff from Taiwan etc, take the labels of the article , place them on their own cardboard approx. 60cm x 60cm printed to make approx. 60 packs .

    They placed 60 items on the cardboard evenly spaced, slid it on a table that had sheet of clear Plastic suspended above the Cardboard, above that there was a heater that was 60 x 60cm made up of a wire mesh.

    The Heater would turn on get hot , soften the plastic and it would drop down over the 60 x 60 cardboard and seal on to the Cardboard and create Bubble Packs
    ** Couldn't you use the same type of heating.. IE : Have the Vacuum frame already positioned with the Vacuum cleaner already connected , but not switched on ,

    With something similar to your heat source or maybe 1 or 2 Bar heaters mounted on a Frame just above the the Plastic.

    As soon as the plastic gets to the heat required,... Turn off the Heat, Turn on the Suction.

    That way there is no need for the separate box and no need to carry from one to the other.

    I have never seen this type of vacuum moulding before , but it reminded me of 1972.... anyhow that was Just a thought ,

    Well done .

    As to the insulation question; I know this would make the unit much heavier, but what about using something like sheetrock, or concrete board (EG: 'Hardy-board') mounted to a wood frame in place of the particle board? Sheetrock carries something like a 4 hour fire rating, and I think the Hardy-board is fireproof, or nearly so. But for no longer than it would be heated up, that shouldn't create a problem (figuring it would only run 3-4 minutes per heating cycle, and with the plastic holding frame in the vacuum former, built up heat would dissipate quickly.
    As for wiring; I wonder how 12 gauge stranded wiring would work, as opposed to solid core (stranded will carry more current than solid core, thus lowering the amp load) in place of the 14 gauge you have now. I would think a single 30 amp breaker fed by 12 gauge Romex would carry your load. as stated above, you aren't running this device for any great length of time, (3 minutes) so, I don't see a serious overload situation developing. If you were running a production line, yes, you might have problems with electrical and heating issues; but for hobbyist work, and considering set up, heating, vacuum forming, and cooling, you might make maybe 4 to 5 parts an hour?
    It is better to err on the side of safety, than to burn your house down, so, these comments are meant as food for thought, and consideration. My thinking is the wiring and insulation changes might lower your total electrical cost by making the process a little quicker and more energy efficient. (Usual disclaimer: Contact a licensed electrician, and a contractor for more information, yadda, yadda, yadda….)

    1 reply

    Thank you for the advice. All of the wiring is stranded. My garage breakers are 25 amps each. I tried plugging it all into one outlet and it popped the breaker immediately.

    I did consider concrete board, but i had seen another example of someone using infrared lamps as a heat source and they mentioned that a reflective surface inside the heating area would help diffuse the heat better so I went with sheet metal panels two kill two birds with one stone.

    Right no this thing gets used once or twice a MONTH for 5 minutes at a time.

    I feel a little lost when I think about your setup. What I'm lost about is why didn't.t you leave it all together, I mean once the plastic is heated just kill the lights and turn on the vacuum . I'm probably missing something but I'm old and that's my excuse.

    1 reply

    I don't quite know what you mean by together? Originally the whole thing was supposed to be collapsable so i could hang it in a space on my garage wall when I wasn't using it. I didn't go for the "stacked" approach that others have, meaning the plastic is heated by an element directly above the vacuum table and then you just slide it down a guide rail to the table. I didn't do it this way because that would have been pretty tall and I have alot of hanging storage around the edges of my garage which would have made it impossible to store out of the way.

    The table, vaccuum, and heater all sit right next to each other when in use. I am planning to add a switch box to the side of the heater box though so that I can do just what i think you are suggesting...being able to turn off the heater and turn on the vacuum in one convinient place.

    The design was heavily influenced by the money and materials i had laying around.

    So your building instructions are nice and clear, but I am totally in the dark about how you would actually use this thing. Does the heating element stand separately? Is it hanging above the vacuum chamber, or is it below?

    Also, what do you make the shapes out of? Don't they need holes drilled in them, too?

    2 replies

    The cover photo shows exactly how i have it set up when i use it. The hot box is to the right. It sits on a janitor's cart bottom with wheels. The vacuum table sits to the left on a pair of saw horses. I place the frame (bottom left) with the plastic (bottom right) in it on top of the hot box and plug in the lamps. When the plastic reaches the right temperature I quickly turn off the lamps and turn on the vacuum table (because my garage circuits can't handle the lamps and the vacuum at the same time). Then I lift the frame and plastic off the hot box and place it on top of the vacuum table which has my object on it. I have maybe 5 - 10 seconds before the plastic cools too much to give much detail, so i move quickly

    The objects i want to form can be made of most any rigid substance. The triangular shapes shown in the picture (which are supposed to be ears, by the way) were carved out of wood.

    If you are going to need alot of detail or the surface of your object has concave areas then you would need to drill holes in the object to ensure the plastic sucks down into those areas. In this case I wasn't going for very much detail.

    Ah! ok, thanks, I probably missed something when I went through the instructable, as it looked to me like you would be placing the full frame+vacuum chamber+former on top of the heating oven...

    Very ingenious, and quite simple.