Found myself an inexpensive Hamilton Beach Sandwich Maker and started experimenting with melting HDPE. Check posts starting from #11 onwards in the discussions for details.
In a recent discussion here at OB we talked about making engineering wax (laced with LDPE) and the subject of recycling HDPE (bottles, caps, ...). So here is an Instructables by Atomic Shrimp which I'm thinking of following to work with HDPE.
How to recycle HDPE (milk bottles and caps) into usable sheet material - All
Right now, I am collecting HDPE - any 'plastic' with the marking /2\ and/or "HDPE". This is milk jugs, water bottle caps, shampoo bottles, etc. Avoid a container which was used to store dangerous products (bleach, etc.) Mix or sort the colours and have fun.
[update 2015-09-23] A recent find worth bringing closer to top of the stack. Here is a young DIYer sharing his HDPE recycling method :
His HDPE related YouTube playlist can be found here.
An alternative approach is suggested by Peter Brown in one of his YouTube :
And an other from Matthew Nayman :
Both of their technique allows for making larger volume 'bricks' from HDPE to carve, mill or route into objects. The first uses a heavy duty blender and the second shows some creative use of cut sheets to create patterns... While both use an oven and DIY press to form the blocks and minimize warping.
The first method only required a good pair of scissors and a sandwich press. It looks easy and quick to create thinner sheet stock.
As always, you are the one responsible for what you do and consequences of your decisions and actions. You have been warned.
How to recycle HDPE (bottles, caps, etc.) into sheets / blocks to CNC 2015-12-04
Some very good Instructables / YouTube showing how to easily recycle HDPE and work with the material