Many thanks Jairus, more drawings coming up shortly.
With most of the brass bent into shape I began to practise soldering, and soon found that my ancient 25W iron didn't have enough power for the job. So the chassis was put on hold and it was back to the body.
As I was using my own designed body I knew that I would have to build a vacformer !!
I checked out the various threads on SlotForum for DIY vacformers such as Howmet's here
and put a lot of thought into how I'd build my own machine, then it was off to B&Q.
I bought some Conti board (cheap as chipboard lol) that seemed to aspire to other things. Little did it know
The first thing I did was to make the vacuum table. Using a mitre saw I cut some lengths of conti board, which I screwed and glued together to form a box open at both ends. I secured this firmly to a base of 18mm MDF (this was an offcut from another project) Note the hole I drilled with a hole saw, to accept the vacuum cleaner nozzle.
I then glued in some supports (to hold the vac bed) made from 3mm MDF and notched together in the middle.
Finally I made the bed of the vacformer. This is where the mould sits.
Using some 3mm MDF cut to size, I marked out the centres of some 200 plus holes using isometric grid paper and set about drilling each of them with a (unfortunately blunt) 6mm drill bit. This was very laborious and I'm sure some sort of grill material would make the job easier, but nonetheless, it works perfectly.
Here it is fastened in place. (It is pinned, but I taped it to ensure better suction).
Next I needed to make a mechanism to bring the vacuum forming plastic into contact with the mould when it is "plastic" enough. So using the conti board again, I made a second open box, larger than the first which could slide over the first like a close fitting sleeve (The outside/overall dimensions of the sleeve are the same as an A4 sheet of paper).
Note the blocks at each side, which hold the sleeve at the correct height whilst the plastic is being heated. Also note the mouse-hole shaped hole that allows this sleeve to clear the vacuum cleaner nozzle, when the plastic is drawn down onto the mould.
To make the frame that holds the vacforming plastic securely in place, I cut two rectangles of 3mm MDF, these are 10mm larger than the sleeve on all sides and overhang (so that they can be clipped together when in use). I then routed out the centre of the two rectangles so that the hole was a tad larger than the vacforming bed. I pinned and glued one of the frames to the top of the sleeve (ensuring that the sleeve still slid up and down the centre box smoothly and the frame didn't impinge on the vacforming bed). The other frame remains loose and is used to sandwich the vacforming plastic.
I applied draught stopper (the rubberised type) to the face of each frame that comes into contact with the vacforming plastic, to ensure a good seal. I was concerned that 3mm MDF might deform in use, but it seems fine. I could add some bracing to the loose frame in future.
The vacuum former was now ready to use, I bought a pack of bulldog clips to fasten every thing in place when in use. Here it is in its first real operation. The machine worked perfectly, unfortunately the mould let me down and I needed some releasing agent. So it was a bit of trial and error to begin with.
I use the heat gun at the side to warm the vacforming plastic sufficiently (just until it begins to get a uniform sag) then I pull out the blocks and turn the vacuum on in one swift and smooth motion. The vacuum helps pull the sleeve down the inner box/vac table, ensuring that the plastic is in good contact with the mould.
I asked Howmet which plastic he used for his creations and he told me that PETG was the best and he recommended a few retailers. I bought my PETG online from 4D modelshop it is clear PETG 0.5 x 500 x 800mm and can be found here
(about half way down the list). I can cut each large sheet up into 6 smaller 294x207mm sheets to fit in the machine.
When I had finished building the vacformer, I had some conti board left over, which i turned into a very useful sanding board.
Next installment...Body Building.