guillotine part 2

The first prototype for the plastic bottle guillotine. The slightly random shape should give me a variety of cuts - using the negative and the positive parts of the bottle once cut. This blade can also be rotated at an angle to produce a different cut.

Using the fly wheel press I attempted to stamp the shape in to the plastic bottle, though I hit a snag - because the plastic bottle is not very strong when the liquid has been emptied, and the force of the flywheel press is so great, the plastic bottles are pretty much flattened, and losing the cylindrical shape is not good.

As you can see above, I tried filling the bottle as best I could to prevent the fly wheel simply crushing the form. Using a block of wood and then a hard rubber length on top of this seemed to work reasonably well, though the cutting blade only made contact with a few inches of the bottle, requiring me to rotate the bottle each time I made a cut.

Also, trying to hold the blade steady when spinning the fly wheel can be difficult and dangerous - its pretty much a "hands-off once you start" bit of workshop kit. Gill, the workshop technician so me a simple way of solving the problem - placing a very heavy weight on top of the blade!

I thought of ways to fill the bottle out, make it slightly stronger, and I was curious when Jon mentioned expanding foam. After spraying a release agent in to the bottle, I poured in the two chemicals seperately, put the cap on and shook them together. The two chemicals need access to oxygen to really kick off so I opened the cap after they were mixed and then waited until the foam was near the top of the bottle and quickly screwed the cap back on.

However, trial and error needs to occur in some cases (this stuff didn't come off my hands for over a week - note to self: wear gloves).

Showing basic 'casts' of plastic bottles using exmpanding foam. The amount of 'hardener' used was slightly different in each one - the right-hand one was slightly tacky and the one on the left had to much air between the foam.

This one was a bit off-course but I had a good time experimenting, it also showed a different manufacturing process that could be applied to plastic bottles - one of the main project goals.

The bottle filled with foam did seem to hold it's shape slightly better than the ones wih out, though after the cutting process, the foam wouldn't budge.

I retried the foam with more release agent sprayed in to the bottle and yet again, once cut, the foam would not leave the bottle.

At this point I felt it was time to change course to a more reliable manufacturing process - the flywheel bottle press was too tricky to try an replicate a cutting shape. Also the bottle's integrity was lost when subject to the crushing flywheel.

Back to the drawing board...