On Thu, 2005-03-24 at 11:18 +0000, Adrian Bowyer wrote:
> Not so much documented as custom and practice. All this sort of thing stems
> from casting technology from the beginning of the industrial revolution: suppose
> you want to make a cast-iron locomotive wheel; you make one in wood (called a
> pattern), you pack that in sand in a box, then split the box and take the
> pattern out so you can use it again, then you pour molten iron into the sand
> cavity...
Fair enough. While sitting outside on the back porch with a glass of
brandy in hand, listening to the post-Easter Egg Hunt chaos, I started
thinking about moulding processes and began experimenting with some HDPE
and PET bottles lying around. It occurred to me that these might make a
cheap source of raw material for at least some parts of the fabricator,
and demonstrate its immediate usefulness to Environmentalists.
I was concerned about the rigidity, but thicker parts such as PET bottle
mouths and HDPE bottle handles seemed to be sufficiently robust. I'll
quantify that later.
Experimentation with a low-cost glue gun and thermocouple revealed that
neither material would readily melt at 130C, and an "improved" glue gun
with stacked heating elements will be constructed when I next go to the
"Two Dollar Store".
I aim to extrude stacked layers of the materials manually, and if the
results are promising I'll knock something up out of Meccano to produce
pipe and lathed shapes. Anyone remember the "meccanograph"? A mechanical
spirograph that produced quite complex shapes. Might be a useful
low-tech approach for making test structures.
Vik :v)
--
Vik Olliver <[log in to unmask]>
Diamond Age Solutions Ltd.
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