Today the Auroville Earth Institute is providing manual presses worldwide to produce CSEB (the Auram Press 3000) through the workshop Aureka, and the mixing is done by hand. But there is an increasing demand for motorized systems, as labour is increasingly expensive in any country.
A hydraulic press already exists to facilitate the pressing of the bricks, but we need to automate also the mixing, in order to match the speed of the process.
This mixer is destined to be used in countries all around the world using the local materials. The machine will be used in different climates; soil may also be different according to the geographic location and therefore might have different mechanicals properties. The machine will be produced by Aureka, in Tamil Nadu, India.
Some motorized mixers already exist in the USA, Mexico, India... But those made in developed countries are quite expensive for India, and those made in India up to now are poor quality and not appropriate to mix soil.
Difficulties for the design
Mixing soil is not like mixing concrete: it is the rotor which should mix and not the frame which should turn. This is due to lumps created by the addition of water.
A Belgium prototype has been created using blades with steel from Japan (high quality was confirmed): after 2 weeks the blades were dead, due to the highly corrosive nature of the soil.
The humidity of the mixture can create stone-like lumps which can destroy a disproportioned container.
One mixer has been designed and developed between 1995 and 2010.