The designs pusblished on this page are licensed under the Open Source Hardware License.

Version 1

Claystruder mounted on the RapMan

The Claystruder is a device that replaces the plastic extruder with an compressed air syringe extruder which is capable of extruding high viscosity materials like clay or cement. The design is based on the original Claystruder by the design studio unfold from Belgium which in turn is based on the Frostruder MK2. Our design takes a 100cc Braun Omnifix syringe which is in stock at local pharmacies for ca. 2.50€ per piece.

Syringe parts. From left to right: syringe, plug for equal pressure inside the syringe, plug for air thightness with connector for compressed air coupling

Part list

  • Syringe
  • Compressed air couplings
  • Compressor
  • Solenoid valve
  • Printed plastic parts (housing, plug, mouting plate(can be laser cut))

Version 2

Prototype assembly

Version two of the claystruder changes the design to a stepper motor driven auger extruder. Auger based extruders work by forcing material into a chamber with air pressure in which an auger rotates and transports the material through a nozzle. The variable motor speed allows for a more dynamic extrusion. Attempts to create auger based extruders are made by a number of different people (e.g. [1]).

Our design utilizes printable parts in combination with a normal drill as auger and an additional bearing. All parts can be easily sourced and are quite cheap. Shematic drawings of the auger housing can be downloaded (File:Claystruder-2-housing.pdf).

Auger housing

Auger housing

The auger housing is completely printable. How well it works with abrasive media is not yet clear and has to be tested. Alternatively it can be made from alloy or other metals. The auger housing takes a normal 5mm drill as auger. On top the drill is fitted into a 105 2RS bearing.

The housing is designed with G1/4 threads for the nozzle and the material feed. G1/4 connectors to almost anything are widely available. The G1/4 threads have to be cut by hand as they can't be printed.


The testrun went well, a constant amount of material was extruded. It's important to note that the air pressure shouldn't be set to high as at some point the material will be pushed through the auger by the pressure alone. The next test should be made with a real stepper motor and the right nozzle.

Version 1.5

Currently I am building a version based on dispensing industry parts which will work in the same way as version one but is more reliable.