I was wanting to make an interesting lampshade as a specal Christmas present this year. I set about searching Instructables for inspiration.
This used a repeated unit which was cut out of polypropylene using a laser cutter.
This concept is a single piece which can be connected in a number of different ways. I used 30 pieces to create a spherical lampshade.
These pieces can be put together in a number of variations, shown here, using up to 120 of these repeated shapes. Its an amazing mathematical puzzle and an incredibly clever concept.
I used A0 sheets of 0.8mm thick frosted clear polypropylene and the pieces were sized to be around 100mm high x 80mm wide.
The polypropylene is available here, from Kitronik. Other plastics can be used, including HDPE which can be obtained from old plastic milk bottles.
I downloaded the .dxf from the instructable and adjusted the size to my application. I needed to cut 30 pieces from the sheet I had, so I sized the shape to fit this. If I were to do it again, I would cut larger pieces to make a much bigger lampshade (or I could just cut more pieces and made the larger lampshades.
I tried cutting smaller pieces but, due to the thickness of the polypropylene, these did not work very well. I might try again with some thinner plastics or card.
Putting the pieces together to make the shape takes a bit of practice and is like a huge puzzle.
I used the instructions from the Instructable, along with a youTube video of construction (of which there are quite a few) and eventually fitted all the pieces together to make a sturdy and beautiful unit.
After building it I managed to find some instructions for putting together the various different sized lampsahdes.
The last thing to do was to add a lamp holder and bulb.
I took out one of the pieces from the lampshade.
I drilled a hole in the very middle of this piece big enough to take a compression gland which will hold the shade on the flex to the lampholder.
I got a ceiling lamp holder, such as this from Wilkinsons.
I disconnected the flex from a lamp holder and threaded it through the compression gland.
You MUST use low energy CLF bulbs in these shades, due to the low air flow and the potential for heat to build up.
Be VERY careful with wiring these, as the fitting uses dangerous high voltage mains electricity. Only wire this up if you are confident with mains wiring and have turned the power off.