The Liberator Beta v1.0 Specifications

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(see corresponding blog post)


Download Open Document Format (ODF)specifications for The Liberator Beta v1.0 here.

Before you continue, here's a brief description of our offer.

We are offering a high-performance, open source, Compressed Earth Block (CEB) Press - The Liberator. This is a CEB machine shown here. It does not include the tractor or power source - just the machine with manual, hydraulic controls. The machine includes a large hopper and a shaker grate for sifting soil into the hopper. The power source is external. This is part of our strategy to obtain a high-power, low-cost machine.

A CEB machine like this is not a toy. It is not designed to be loaded by hand - as it would take about 32 people to load it by hand to keep up with its proven demand for soil. Soil handling is a major requirement at this scale, and requires a tractor loader plus some way to pulverize the soil. If you are interested in a machine that you can load by hand, just get a hand-operated (non-powered) Cinva Ram or similar for $200-$500. You will save yourself the cost of purchasing a machine that you will not be able to use effectively without a tractor and soil pulverizer. We learned this the hard way with our first prototype. Read about our experience in this blog post.

Doesn't it make sense to have a dedicated engine on the machine? We don't think so. Any construction site at the scale of building intended for this machine will have a tractor or skid loader on site. Auxiliary hydraulic power can be used from these machines to operate the CEB press. We favor the Power Cube for a power source. You can get a PTO-driven hydrauilic power source for about $800.

Equipment Ecology

The external power source strategy of FeF is designed such that a large number of machines, including tractors, have interchangeable power sources. This allows an entire mechanical infrastructure of a 10-100 person village to thrive with the assist of a total of 40-80 hp in engine power. For us, we're exploring modularizing this to 20 hp Power Cubes. This way, a machine can utilize 20 hp as needed, or several PowerCubes can be attached to another machine, such s 4 Power Cubes for a bulldozer. We're going further on this to develop steam power, with locally grown, pelletized biomass as the fuel source.

For more information, scan all of our experiences with this CEB press under the CEB category - . You can find out about the mechanical infrastructure, agriculture, construction, and fabrication aspects of FeF at Linz Slides.

Specification of The Liberator Beta v1.0 Product Release

Note: the following is a table of specifications exported from Open Office on Ubuntu 8.04. The formatting is poor. If anyone can help format this better, you can download the source file here, and email us at opensourceecology at gmail dot com.

The Liberator Beta v1.0
Open Source, High Performance CEB Press
Beta Release Product Information
Factor e Farm, November 3, 2009

Model The Liberator Beta v1.0 Product Release

(last version was The Liberator Prototype II[1])

Release Status Limited Production, user testing, user co-development
License OSE-Post Scarcity Economics (OSE-PSE) License[2] (compatible with CC-BY-SA, GPL for hardware, and OSE Specifications)
Press Type Hydraulic, manual, vertical press
Production Rates

- with 8 GPM fluid flow[3]

- manual control[4]

- automatic control[5]

- with 15 GPM hydraulic flow[6]

4 blocks per minute

5.5 blocks per minute

9 blocks per minute

Theoretical maximum production rate[7] 12 blocks per minute
Size (LxWxH) 5.5'x5'x8' – fits on a ¾ ton pickup truck bed
Special features - open source business model

- Design-for-Disassembly (DfD)

- Design-for-Post-Scarcity (DfPS)

Power source Not included[8]
Operating system pressure 2300 psi
Cylinders (Bore x Stroke x Rod) 5”x8”x2” main, 2.5”x14”x1” secondary
Compression force 23 short tons
Block Size 4 1/4”x6”x12”
Variability of block thickness[9] +/-0.1”
Materials Cost, Prototype II[10] $2902
Weight, Prototype II 1922 lb
Predicted Materials Cost, Beta v1.0 $2095
Predicted Weight, The Liberator Beta v1.0 1650 lb
Soil requirements, cubic yards per hour:

- 4 blocks per minute[11]

- 9 blocks per minute



Hopper size (LxWxH) 6'x5'x3'
Hopper loading Manual, conveyor, or tractor loader, especially LifeTrac Pulverizer-Loader.
Grate shaker 1.93 cu in hydraulic motor with 6 lb eccentric hammer
Included features Complete CEB machine with hydraulic system (but NO power source); grate, grate shaker, 2-spool manual control valve, hopper extensions, large hopper, user manual; ready to plug into hydraulic source of 12 GPM rated flow
Price FOB Kansas City area, Missouri; limited production run of 3 machines - $3500 for True Fans[12]

- $5500 for all others

Delivery and assembly options - You pick up the assembled machine yourself or arrange for shipping

- We disassemble, crate, and ship the machine on a pallet (disassembly/crating fee of $300, plus shipping)

- We ship assembled machine by truck freight (no disassembly/crating fee, but shipping may be more expensive)

Delivery time 21 day on-demand fabrication time, from receipt of FOB payment in full
Options - Pre-purchase of automatic control module - $750. Auto controls module will be real released within approximately 2 months.

- Power Cube hydraulic power source with 17 hp engine - $1500

- Tractor PTO-driven hydraulic power source, 15 GPM - $800

- Trailer for easy transportation - $1000); standard mobility is via forklift carry tubes

- 12 GPM Quick Couplers to all cylinders and motors - $250[13]

- Up to 24 gpm Quick Coupler flow connection into main valve -$200[14]

- Pressure relief valve – $50

- Needle valve flow reducer, 0-25 GPM - $60

- On-demand customization

- Spare abrasion liners – to be determined upon more complete abrasion requirements, but materials cost for each linear are low at about $5-10

- Lifetime Warranty - $4000[15]

Future developments - Automatic control module retrofit

- Brick roller conveyors, 10' sections

- Soil testing kit

- Open source house plans

- Fabricator training

- Fabrication optimization, CAD, CAM digital fabrication files

Warranty DfD design and ready replacement of parts constitute our guarantee of long service.[16] See the Lifetime Warranty under Options above.

Brick thickness detail including standard deviation

  1. See
  2. In progress.
  3. Using the available Power Cube for testing. At max throttle, the existing system delivers 8 GPM at the workingcylinders.
  4. Achieved using Power Cube by pressing 4 1/4” x6”x12” blocks in a set of three, timed, 5-block runs. Times achieved were 1 min 24 sec, 1 min 24 sec, and 1 min 10 sec with an unskilled operator.
  5. Automatic control pressing rate was determined by measuring repetitive motion times for each cylinder, and averaging over the number of cycles – using an empty hopper and manual controls. This was done to minimize operator dexterity limits of determining automatic control pressing rate, without actually using automatic controls. Brick production rate was determined as the sum of the average full cycle times for each of the two cylinders.
  6. Done by using LifeTrac as a 15 GPM fluid source at medium-high throttle. Manual controls were used to infer production rate as in footnote above.
  7. 15 GPM flow resulted in a cycle time of under 5 seconds for the large cylinder. We believe that this could be brought down to as little as 3 second per cycle. The full cycle time observed for the secondary cylinder with 8 gpm flow is 2 seconds. Thus, a 5 second overall cycle time is predicted – or 12 bricks per minute. At this rate, the limiting factor are soil loading dynamics of gravity flow, which is assisted by hopper shaking.
  8. Any external power source of up to 25 GPM may be used, such as LifeTrac and Power Cube. Tractors and skid loaders are 2 good, mainstream options. Skid loaders typically have 17 GPM auxiliary hydrauilic flow, such as Bobcat40 hp range models ( up to 34 GPM in the 80 hp models. Gehl 80 hp models have 23-36 GPM auxiliary hydraulics. Sample modern tractors – 45 hp AGCO - 14 GPM - ( Case has 20-range GPM ( See other websites for details.
  9. See thickness data set below for a 25 brick sample. This variability is defined as the standard deviation.
  10. See Bill of Materials elsewhere.
  11. Assuming each brick weighs 15 pounds, and density of soil is about a ton per cubic yard
  12. See for True Fans. This special price applies only to those who have signed up during The Liberator development cycle prior to November 1, 2009 – ie, those people who were instrumental in funding the actual devleopment of The Liberator.
  13. Allows easier storage and setup, but limits flow rate compared to hard-wiring, which supports up to 25 gpm flow)
  14. 1” flush-face coupler s allow up to 26 GPM flow -
  15. This is a Beta Release for testing performance. You should read the blog posts, OSE project management site on Open Pario, and other supporting information to understand the state of development. The initial release will be a fully-functioning machine, it will still require a number of optimizations, to streamline both the operational aspects of the machine and the fabrication procedure. This is because a product evolves over time to a stable release, and even then, upgrades and customizations can be made. You are purchasing the Beta Release to support our development (cont.) process. We offer the Lifetime Warranty if you would like to exchange your machine in the future for the latest stable product release, if you deem that desirable. In that case, we ask you to bring your old machine back to the Factor e, and we will exchange it for the latest version. This allows us to salvage valuable parts, and it allows you to have the final, lifetime-service product. Both parties win by helping the open source development process arrive at a stable release as quickly as possible. All money invested into the project goes back into continuing product development. You have a limit of one exchange, and you may choose not to use it if you are satisfied with the Beta Version 1.0. You are expected to pay cover the transportation costs for returning your old machine and shipping the new.
  16. All parts are replaceable and easily obtainable, and the DfD allows for quick service. Wearable parts (compression chamber liners) are to be replaced depending on the usage of the machine.. The machine is guaranteed to be free from any defects. Wearable parts are the responsibility of the user. Liner replacements cost about $5 each for materials, and there are 8 liner parts. Each liner should last for about 20,000 bricks pressed. Hydraulic seals may have to be replaced every 5-10 years.

Brick Thickness Data

Brick thickness data with error bar showing the standard deviation:


The data was obtained using raw soil from near the machine. Topsoil was scraped off, and the Soil Pulverizer was used to prepare the soil. Brick thickness is determined in The Liberator II prototype by timing the compression stroke until full compression occurs with 2300 psi.

An alternative route to perfecting thickness uniformity relies on a limit switch, which stops compression at a preselected thickness. As of 12.15.09, this is currently being implemented.

Bill of Materials

See the complete Bill of materials for The Liberator II, and the Calculated Bill of Materials for The Liberator Beta v1.0. The latter shows the optimizations in cost and weight resulting from a number of minor modifications.