Introduction: Melting Hdpe Plastic
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Step 1: GATHERING PLASTIC
first you need to find some HDPE it is number 2 with the recycling triangle or most milk bottles and bottle tops
Step 2: Process the Plastic
cut up the plastic or use a blender ( if you use the latter it will contaminate the blender and be unusable for food )
Step 3: Melting the Plastic
the tools you need are toaster oven or oven if you are using a oven you will need a tray that you cant use for food and a vise
set the temp to 175 c or 350f
Step 4: Restock the Plastic
you will need to restock the tray you can use pre melted hdpe or milk bottles
Step 5: Done

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14 Comments
3 years ago
Can the melted HDPE be colored with some substance?
5 years ago
I've worked with HDPE, LDPE, PE and PP. I found you don't have to cut it up much too start, just clean it, remove labels and melt it. But I melt it at 375-400 F for an hour or more, remove it, fold, twist, knead it, then heat again at least 3x. Then I take it out and push it into a mold made of wood and apply as much pressure as possible until it cools. The result is a super hard, solid piece of plastic with no voids. I can then sand, cut, drill, polish the blocks any way I want. I've made a bunch of handles for tools and knifes, coasters for coffee table, oversized plastic washers, desktop webcam stand, etc.
Reply 5 years ago
I've been working on iterations of this project ever since I published it , with a completely new set of tools they have opened up a new world of possibilities including a project with laser cutters and 3d printers. I am revising this post and adding much much more this year coming
thanks for an insight into your way of doing this has given min a few ideas myself
, keep making
Jimmy Crawford
7 years ago
This can be used to cast figures, like instamorph?
Reply 7 years ago on Introduction
if you could get a heat proof mold you could melt it into it but other wize it get really hot and it a gum like consistency so no sorry by you can carve it
thanks for looking at my instructable jimmy from kidintheworkshop
Reply 7 years ago
but i supose
Reply 7 years ago
What if uses clay and a wax model?
Reply 7 years ago on Introduction
i dont know what you mean it is not liquid it is taffy but instead of using a tray use your mold blend it real fine thanks please vote
Reply 7 years ago on Introduction
https://www.instructables.com/id/Lost-Wax-Casting/ here is an istructable with the lost wax casting, for make models, but if you say is not liquid .... voted
Reply 7 years ago on Introduction
o i didn't know what you meant i have done some lost wax casting in alumulum , tin and lead
7 years ago on Introduction
i did melted a lot of hdpe and from experience hdpe when melted will not turn liquid it will be more like thick taffy if you want it to be completely flat you could clamp it down between two boards while still melted this way your plastic will be completely flat. and keep in mind that not all hdpe is the same because most containers like the ones you used in the video are blow molded and blow molded hdpe is higher density which makes it less flowable when melted on the other hand 5 gallon buckets are normally injection molded which uses a lower density type of hdpe that flows into the mold without pressure however the higher density hdpe is stronger
Reply 7 years ago on Introduction
you are completely right that why and do it it in lots thanks kid intheworkshop
7 years ago on Introduction
Nice way to recycle everyday materials.
Reply 7 years ago on Introduction
my recycle bin is empty because of this and i like this plastic because is strong and you can remelt it in to new shapes thank you jimmy from kidintheworkshop