So, I optimistically said I will make a vacuum former as my first project. I may not have been inducted to woodworking yet, but how hard can it be? (famous last words)
However, I did all the research into the numerous instructables and DIY videos an drew up a design that I think combines the best of simplicity and effectiveness. By the time I can cut a piece of plywood, hopefully I will have refined the design and figured out the electrics for the heating element.
The main features of the design are:
The effective working area will be around 40 cm x 40 cm, so double that of the Formbox (on Kickstarter), which I think it is a decent size for most projects.
I would prefer the perforated surface to be made with a metal sheet, but I don’t know how easy this is. I know you can buy perforated metal sheet, if need be. Failing that it can be made with wood.
The frames, that the thermoplastic sheet will be sandwiched in between, will be made using aluminium corners and held together with bulldog clips all around. (The frames could also be wood, but I prefer aluminium)
The top half of the aluminium frame will have a pair of wooden handles attached to it, with holes so it slides along the 2 metal rods on each side.
The rods will be inserted into the wooden blocks that will be attached to the base and heater boxes. This way, when the vacuum former is not in use, the two boxes can be taken off for easier storage.
I opted for vacuum provided by a hoover plugged at the back of the base box. A vacuum pump will be more effective, but will make the set up less ‘portable’. However, this can be easily changed.
Heat will be provided by an electric oven’s grill element. Buying one is cheap, but I’m not sure yet what electric bits and pieces are required to make it work. The heater’s box will be lined inside with insulation.
My intention is to leave the former at SLMS, if there is interest and space to put it, but I will happily take it home, if there isn’t.
Not so sure about a plywood box with a grill in it .
A whole bunch of halogen bulbs would be a lot less likely to catch fire and control because they will spend less time on
I have seen the set up with halogen bulbs only in one DIY project. The wiring looked rather messy and required a lot more infrastructure to hold all the bulbs in place. Everyone else has used an electric element, hence the insulation inside the box. Maybe the box not made of wood? Or use a fire retardant?
As far as halogen bulbs go, this looks much more sensible than what I have seen used. How do you calculate the heat output to know you have used enough bulbs? We’d need to evenly heat the 40cm x40cm thermoplastic to a maximum of around 200 deg C (for polycarbonate), but more likely to 160-180 deg C for ABS or PS.
What would you build the box for the bulbs with, in that case?
A quick back of the fag packet gives me the tubes spaced at 220mm with 110mm on the edge and the work peace at 110mm with a flat reflector 20 mm behind the tubes bent up at 90 degrees at the edges to make a 440mm wide lamp.
And before anyone dose a computer model my calculation was done on the back of my fag packet but I reckon it will be flat to within 3dB
A couple of tips:
What do you want to make with the vacuum former? It is best to make the vacuum former to suit the final product you intend to create.
Alternatively make it to suit the size of material you can easily get otherwise you will waste much of your plastic sheet.
Choose a design from the web that someone actually uses to make stuff with on a regular basis. Try replica prop builders’ forums.
Check out James Bruton’s version on Xrobots.
