Open Source Soil Mixer 2016

Intro

To produce stabilized CEBs with our open source brick press, and to begin economically-significant block production - a mixer is needed for uniform mixing of soil and cement (lime or portland) in about a 5% proportion by weight.

Here's a commercial alternative: "The way the guys in San Antonio, AECT, do it is to have a massive hopper with reverse tines in it, then they auger that dirt and cement into a hopper that gets dumped in a heap mixed with a front end loader bucket and sprayed with water until the whole pile is uniformly gray and clumps under hand pressure and falls apart when dropped…then they press it. This machine costs over $100,000."

Build

• Build was started during the CEB Press/Power Cube workshop with most of parts cut out by Shayna and Eric?
• Finishing with bending steel over a round edge. It turns out that welding on slats perpendicular to the direction of bending allowed the 1/8" steel to be bent into a perfectly round shape using a lever arm and using bolts to do the pulling
• Closing lid was added at end
• Different motors can be interchanged - coupled via a double-chain coupler with modular motors carrying their own sprocket half
• tines are bolt-on, and work up to 10 cu in motors, but bolts got loose on the 45 cu in motor
• See 70 steps of build procedure here:

Dry Run

• Uses fast rotor, 650 RPM, 5 cu in hydraulic motor driven with 14 GPM hydraulics
• Not enough torque once 5 buckets of soil are used
• Switched to 10 cu in and finally to 45 cu in, the latter being 15,000 in lb of torque

Soil Mixing Initial Tests

• Success. Need to tighten down bolt-on auger, see stall in second video.