Intro: 3D Printed Bio-plastic
3D Printing is an amazing technology and gives a lot of possibilities to architects, designers and customers. But there are two things that annoy me about it. The size of a 3d print is limited and it’s getting very expensive to print something that is larger than a cup or a smartphone case.
By accident I discovered recipes for bio-plastic. After several tries I got the idea that I can use it for 3d printed architectural structures. It´s a cheap way to print big objects.
Step 1: Materials and Equipment List
Gelatin powder (optional)
Food coloring (optional)
Silicone cartridge (empty)
Step 2: Measure Out Ingredients
120 ml of cold water
10 ml of glycerol
10 ml of vinegar
40 g of cornstarch
5 g of gelatin (optional)
You can also change the quantities of the ingredients. For instance, more glycerol will make the plastic more flexible. And the more starch is added, the more dense it becomes. You can try to add 20 g to 60 g of starch.
If you want to print bigger objects, you can adjust the amounts, as long as the ratio remains the same. To fill one silicon cartridge I use 2 times the quantities.
Step 3: Cooking
Pour the liquids in the pot. Then add the starch and the gelatin.
Turn on the plate. Stir mixed ingredients until there are no clumps.
Continue stirring mixture while heating.
Soon the mixture will get thicker and it should turn into a white, slightly translucent gel. This process happens quickly (30-60 seconds). Now you can reduce the heat.
Stove the mixture for 2-3 minutes. And DO NOT stop stirring.
Shortly before completion add the food coloring and stir again.
The water evaporates during boiling the mixture. Thus cracks are avoided when the mixture dries. The boiling time depends on the quantity of ingredients. But be careful not to overcook. Otherwise the mixture gets so dense and you can’t press it through the cartridge.
Step 4: Printing
Fill the mixture into the cartridge and start your printing process. Place plastic foil underneath.
Begin with a small object. So you get a feeling for the behavior of the material.
Don’t prepare more mixture then you can fill into the cartridge. The mixture begins to dry and can block the cartridge.
Step 5: Drying Process
The easiest way to dry your objects is to put it in a warm room for some days.
If you want to speed up the process, you can put your object in the oven at 60°C for at least 30 minutes. The duration depends on the size of your object. It can take up to some hours.