How to recycle HDPE (bottles, caps, etc.) into sheets / blocks to CNC 2015-12-04

[update 2015-12-04]
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 now not so recent discussion thread here at OB some were talking about making their own "engineering wax" - wax laced with LDPE - and the subject of recycling, or should we say UPcycling, HDPE (bottles, caps, ...). So here is an Instructables by Atomic Shrimp which I'll be somewhat following to work with HDPE reprocessed with my Sandwich Maker.

How to upcycle HDPE (milk bottles and caps) into usable material - All



I have collected HDPE for a while now, checking all plastic items heading to the recycling bin for the /2\ and/or "HDPE" marking. This includes milk jugs (I have not seen / used those for a while now), lots of water bottle caps, shampoo bottles, etc. Avoid all containers which held relatively dangerous products (bleach, pool chemicals, etc.) unless you are not planning to use your upcycled HDPE for an item coming into contact with skin or food.

There are plenty of colours available, especially with those shampoo containers as well as containers used for laundry liquids. You will just need to convince the spouse, kids, neighbours, ... to change the brand from time to time.

I also recently learned - I learn fast, but you just have to explain slowly - plastic grocery bags are most likely made of HDPE as well. We used to keep them for the cat's spent litter ... The problem with the more recent plastic grocery bags is they often include starch - biodegradable corn or potato based starches. Alternatively, they might have UV absorbing compounds added so sunlight degrades them. Not that a bag any where inside a recycling mountain will see much UV light, much less sunlight ... However, it is a nice try to be or at least appear to be 'green'. Upcycling could be a better alternative. Heck, the gifts you will make from the reprocessed HDPE might last 1,000 years ! So don't forget to put your name somewhere on them.

Start your UPcycle bin and collect all those HDPE containers to reprocess at home into some fine CNC'ed art work or even ... practical stuff.

All you need is to cut up HDPE made containers, something to bring the HDPE to about 190°c - melt the stuff don't burn it - and a strong form/mold, with clamps, to shape the cooling HDPE into a block your CNC machine can work with. You will have an infinite source of material to work with. If on the off chance you don't like a particular piece, shred it, remelt and try again !

An other video worth keeping close at hand is from 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 'bricks' from the upcycled HDPE. Blocks which can be carved, milled, lathed or routed into objects of art or practical use.

The first uses a heavy duty blender.

The second shows some creative use of cut sheets, which you could make, to create patterns.

Both use an oven and a DIY press to form the blocks and minimize warping during the cooling phase.

The first method uses a good pair of scissors and a large sandwich press. Makes for an easy and quick way to create thinner sheet stock.

For now, I am using the tiny and inexpensive Sandwich Maker along with an upcycled CD / DVD and credit card confetti/cross-cut shredder the office was avoiding - the safety broke and it wants to shred as soon as the power is turned on.

As always, you are the one responsible for what you do and consequences of your decisions / actions... You have been warned. The stuff is HOT and GOOEY. If you apply too much heat, it will release fumes which can be dangerous. You want to melt the stuff, not burn it !