I’ve made a bunch of progress on the vacuum former. It’s all blocked out now and I’ve pulled a couple tests, definitely a proof of concept, now I can see where I’m going. It’s all there, next i’ll need to fine-tune and get working well. Here is a breakdown of the work so far.
I started by building a custom table, designing it to fit the vacuum former and be a better work bench.
I sized it to fit a pair of 2×2 platens as well as a monitor so I’ll be able to easily access a computer while I’m working.
Below the workbench I added shelves to fit my tools. Bonus organization!
2ft square platen and hinged frame for plastic, Not bad progress considering I’m using mostly parts I had, still needed a couple big things before I can use it.
Using a window sash lock to clamp the frame.
Thanks to a friend who runs the Goldengate knights, I was able to invest in a few parts to continue; a heater, vacuum, tank…
Next I plotted out the arrangement of the heater, platen and frame, by clamping everything in place.
Converting some old server rail sliders to carry the frame from heater to platen.
Finished the insulation and rigged the frame/shop vac for a test pull from the vacuum former. Not great. It reached 145-170f and managed to soften the plastic some, but it needs more, the frame needs more grip and suction needs to better seal
The thermometer was located on a side, so it wasn’t accurately getting the center’s temp. After an hour under there I only managed to get this much melt, so I’ll have to see what else can be done to raise the heat distribution.
I’m limited to 110v from the wall, but can either try reducing the distance between the heater and frame, closing the gap between the oven and frame, or trying to run an additional heater from another circuit.
I think could get two 110v circuits, but doubt I’ll have access to anything better any time soon.
Getting a tighter seal for the vacuum will help a bit, but I need to soften the plastic more too. I’m sure there will be some gain just by closing the gap between the heater and plastic, might be worth picking up an IR thermometer just to get some better readings of the heat in the center.
But sounds like second heater might be the best bet short of wiring up some NiChrome coils.
Otherwise I’ll have to completely build a new heating element. Do-able but it would be a ton of work.
Lowered the heater about 4in raised the frame and tightened the seals for the frame clamps and platen. It’s a bit betted, but still heating unevenly, and not reaching the edges. Thinking its a limitation of the heater’s size/shape. I might need to bite the bullet and build my own heater.
This appears to be the best/recommended source for the coils and ceramic stand-offs, http://www.infraredheaters.com/nicrcoil.html