Planing HDPE

My friend at work, Pete, recently started collecting and recycling HDPE bags, bottles, and scrap from the Betty Brinn Workshop to melt it back down into usable sheets of plastic. The process involves heating the plastic in a toaster oven so that it almost "liquifies" or at least becomes playable and mashing it down, so that once it cools you have a solid hunk of plastic.

At this point your probably wondering, "Whats the point?"

Well the significance to recycling HDPE back into usable sheets is vast. HDPE is a plastic that we use at the Children's Museum pretty exclusively because it is dense and stands up better to abuse than plywood or MDF. HDPE is also the material that cutting boards are typically made out of so you know its durable. Other uses for getting it back into sheet form is now that it is a solid form, Pete can take his creations over to our CNC machine and mill out custom parts again!


For more information on the process and to see Pete's various successes and failures with the material, I would highly recommend you taking a look at his website:

But wait there is more to the process. Pete approached to to ask if I could use the planer in my family workshop to get it down to one consistent size. At first I was sort of apprehensive because I didn't know how the material would react.

But I accepted the challenge.


The first piece that I tried was a success. You can see there are a few voids in the material due to air bubbles being trapped during the heating and cooling process, but not bad at all!


2/3 isn't bad for my track record. On the third and final piece that Pete wanted planed, it "exploded" inside the planer. One of the blades hit a crack/weak point, heard a loud "POP" and quickly shut off the machine.

Luckily no damage was done to the machine and I used it the next night to plane more cutting boards.

Now I was reading online that HDPE shreds as opposed to creating saw dust so I removed the dust collector so the fan wouldn't get clogged by the shredded plastic. What I didn't know however was at what velocity the shredded plastic would come out the tail end of the planer.

I kid you not, shredded HDPE plastic flew 20 ft across my parents basement.

It was a glorious sight.

Have I mentioned how much I love my parents?

(Sorry Mom and Dad!)

I collected up the shavings (at least those that I could) and gave them back to pete to start the whole process over again.


  1. Do you think attaching the HDPE to a large board as a base would help? It would have to be secured really well, but I think the flat board would help keep things on track.


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