A Vacuum Former that also function as a stackable storage box

20 July 2016

Recently, the desire to make clear or opaque plastic canopies, wheels cowlings and nose pieces has gotten stronger. I considered folding techniques, stretch-moulding and after thinking somemore, believes a proper vacuum former will give a better result and it doesn't necessary have to be complicated or wasteful while becoming an eyesore wasting space when it is not in use.

I would prefer to have paid a small price and get a well made one then to make one myself, but since it is not available, here's an idea for a minimal fuss vacuum former.

The main components are 1) a vacuum chamber, 2) a frame for the thermoplastic and 3) the heat source. If I should make one I know I won't use it much, because that is me, however the most part of the fun is had if I should. I just have to bear in mind not to clutter and keep things simple, cheap and easy, and I think that a converted plastic storage box is a good basis to make a vacuum former.

The vacuum chamber:

1. Check that the 20+ years old house vacuum cleaner still works, measure the vacuum tube's diameter. If mine doesn't, I am not going to buy a replacement and this project will be abandoned.
2. Buy a small plastic box to be the vacuum chamber. I am only interested in very small mouldings but I want the box to be sufficiently big to store  the paraphenalia. Maybe I can find something at Daiso. At $2 each, it won't break the bank. Choose one that has sufficient depth to accept the vacuum tube and sealing rings.
3. Cut a hole in the side of the box. It should just be big enough to slip in the vacuum tube.
4. Cut two rings that will fit over the vacuum hose out of some compressible epp-type foam of perhaps 10mm thick. Maybe I can find discarded blocks or sheets of foam rubber.
5. Hot-glue one ring to the inside of the box, over the hole made out to receive the vacuum tube. Tape the other ring to the vacuum tube. Tape around the vacuum tube if necessary to have a snug fit against the inner ring. Check and adjust so that the vacuum hose fits snugly to the vacuum box. The first ring will form the seal, the second ring that is taped around the vacuum tube positions the tube against the box and forms the secondary seal.
6. Drill small holes at the bottom of the chosen plastic box. If the object to form is very small, excess holes can be taped over. Place the box upside down, i.e., with the lid downwards and  the perforated bottom topmost, stick the vacuum tube in and we have a vacuum chamber. Once vacuum forming is done, remove the vacuum tube and the vacuum chamber reverts to a storage box when it is placed upright. The box can then be used to store small pieces of thermoplastic sheets and mouldings, the second ring, plywood frames and male plugs, tape, hair-dryer, heat gun, stapler, staples etc, anything that doesn't fall out of the holes in the side and bottom of the box. We have a vacuum chamber that reverts back to  a storage box and since it is one of those plastic box, it is stackable too, saving footprint.

The frame:

There are a few options for the frame. I prefer option 3:

1. An identical plastic box, either the bottom box or the box's lid with a centre cutout, but then I have to figure out how to secure the thermoform plastic (tape perhaps?) and it will cost another $2.00?
2. A simple rectangular timber frame made of wooden strips that fits loosely around the bottom of the plastic box. Use angle brackets but ensure sufficient width of timber is still exposed as this will be used to staple the thermoform plastic sheets. But the cost will go up because I have to buy everything including the brackets, nails etc.
3. A piece of ply wood with a center cutout. It is not necessary for the cutout to follow planform of mould, afterall, it is plunge moulding. After use, this plywood piece can be stored in the vacuum chamber box for future use. The thermoplastic only has to be as large as the frame, and since the frame can be made small, I won't need large pieces of thermoplastic. Yes, I have to buy or find a piece of plywood, but I think it will cost less. A slight tweak to this option is to use ice cream sticks stapled to form the frame.

Heat source and use:

Thermoform plastic sheet will be stapled to the frame and heated on the underside by a hair-dryer. Then the heated framed plastic will be brought down over the vacuum chamber and the hair-dryer moved to the topside. If my hair-dryer can't heat the thermoform plastic sufficiently, then the options would be to 1) use the gas hob, 2) buy a heat gun, 3) use the toaster oven. I don't suppose hot water will work well. Regardless of choice of heat source, bear in mind it depends on the size and type of thermoplastic I will be experimenting on.