Introduction: Casting Molds With Thermoplastic

Hello! Today I'm going to show you how to use 3D printer to make molds and thermoplastic to fill them.

Step 1: Materials

For this project you will need:

  1. Thermoplastic
  2. A small pot
  3. Water
  4. A stove
  5. 3D printer or access to a 3D printing service
  6. PLA filament

Step 2: Printing the Molds-Moai

Download the files and follow the steps below.


Upload these files into your slicer and slice them. After that, export the g-code to whatever folder you use for you g code files. Keep that print time in mind when scaling the files up or down. Load the new g code files into your 3D printer (I use a PRUSA is MK2, so I just put the files onto a SD card, but if you have a wireless printer, just upload the files wirelessly). Start the print and you are done.

****STEPS FOR SOMEONE WHO DOES NOT HAVE A 3D PRINTER Choose the printing service you want to use. I recommend that you use 3D hubs, since their file sharing system is very easy to use. Upload the files and chose the hub you want to use. The hubs also give you the option of filament you want to use. Most filaments would be fine for this project, just use common sense when choosing. For example, printing this crossbow in a super flexible filament would not be that great of an idea, since the functionality of a crossbow is based on having a tense frame. The site will guide you through payment and the hub will give you an estimated delivery date as well.

Step 3: Prepping the Thermoplastic

This part is very simple. It ought to take about 15 minutes.

  1. Pour a bout a half a liter of water into your pot. Set the pot to boil for about 5-10 minutes.
  2. Fill a dixie cup with thermoplastic pellets, and pour it into the pot.
  3. Let the pellets sit in the pot for about a minute and stir for another 4 minutes.
  4. Take out the plastic once it has turned clear.
  5. Pour the plastic into the mold and wait for it to dry.

Congratulations! You just made a moai statue with thermoplastic. If you want to make a colored version, here's a link to another instructable I did about that:

*PS. my model was not as good-looking as I hoped, so I used the above picture from Thingiverse. It looked similar to my final product, but you always want the best image for your cover. Credit for the link:

Makerspace Contest 2017

Runner Up in the
Makerspace Contest 2017