THREE DIMENSIONAL PRINTING WITH OLD MILK BOTTLES.

THREE DIMENSIONAL PRINTING WITH OLD MILK BOTTLES. I have posted, including here, about the promise of three dimensional printing and on how to do it. Apparently, there is an annual race in Seattle, the Milk Carton Derby, for which entries must be made from old plastic milk bottles. Typically, entries are made by sticking old bottles together to come up with a make-shift raft. This article in the Economist (November 3) tells how some engineering students built an entry that was a boat (rather than a raft) from shredded and melted bottles. The liquid was then used to make the boat by three dimensional printing. There is a picture of the boat being paddled in the Economist article. This article in the Seattle Times points out that although the process has the economic and environmental advantage of working with cheap material that is hard to recycle, the material, HDPE (high density polyethylene), is “the worst material to deal with for 3-D printing because it doesn’t stick to itself.”