$30 method to make compressed earth blocks (CEB).

I have been working for a few days on a project to construct a highly affordable method for manufacturing a CEB. If you are familiar with CEB construction than you understand that these machines can be incredibly costly which limits use. I wanted to have the option for making CEB for retaining walls or raised bed gardens so I did some research on making something good enough and affordable for those small projects. So far I am almost finished with my design but I hit a snag with the block mold. I did the press in Solidworks below.



The press should generate over two tons of force. I decided to go to Lowe's Home Improvement today and spent a little over 30 dollars in materials to construct the press. There is about 9 inches of clearance from the base to the contact board where the force is directed.





Again, the compressive force from the press pulled out the screws from the wood easily when I tried to form a block from clay soil. I wish I took a picture of the block I made but it clearly had enough compression to harden significantly which proves the viability of this economical method for constructing CEB. Here is the very basic mold I constructed.



SO this leaves me with the final design challenge which will require me to construct a mold which can be withstand the compressive forces applied by the press. I will also have to look into making an efficient process to extract the block from the mold. Obviously when the dirt is compressed it creates increased friction along the walls so in the next few days I will potentially have the mold constructed of two pieces - the outer wall to confine the internal stresses and an inner wall which will allow me to extract the block.

Screws will never hold, a corner brace or better yet, steel shipping banding around the wood might be strong enough.

The press looks like the one used to make sawdust briquettes.

http://home.fuse.net/engineering/ewb_project.htm

Looks like it will work good for you.

Yeah, it is essentially the same design. A compounded double leverage press (more accurately called) is a simple device used years back. I have seen examples of these things used for cheese, juicing to briquettes but I never seen a design for CEB. I was cut for time so I made a test mold which I knew was going to fail but wanted to evaluate the concept. In the next few days I will concentrate on a reusable mold design which which will complete this project.

drill holes all the way through the shorter sides on their long axis and use bolts and big washers. you'll need a long bit, and it would be easier with a drill press, but doing it by hand could work just fine, too.

I could easily make a mold that can hold the compressive forces, but I need to make it CHEAP CHEAP CHEAP. If I add metal braces to the design I would easily spend over ten dollars not including the rest. Anyways, this weekend I will be finalizing my cheap mold design so I can finish my project.

tel jetson wrote:drill holes all the way through the shorter sides on their long axis and use bolts and big washers. you'll need a long bit, and it would be easier with a drill press, but doing it by hand could work just fine, too.

thinking about this a little more, you wouldn't need to drill through the short pieces at all. just bolt the two long pieces together at the ends, and place the short pieces so that they will push outward against the bolts. screwing them in place should be enough, then.

shouldn't add much more than $3 to your cost, maybe less. educated guess on price: bolts for $0.35, nuts for $0.20, and washers for $0.10. works out to $3.00 plus tax.

scrounge up some scraps of appropriately sized metal and buy a couple of beers for a local welder..or neighbor who has a welder...you'll go through alot of molds using wood, no matter how well built they are.

Thanks for the link abve to the biomass briquette stuff...that is something I knew nothing of, and have been looking for another use or two for the sawdust out of my sawmill.

come to think of it..it is too bad you are not closer to me...I would weld them up for you. think barter though...barter, is a big part of permaculture. <GRINS>

Could Amed, a moderator or admin edit the post that has the two photos that are next to each other so that they are stacked instead of side by side please? They are stretching the page on my laptop and making it very difficult to read the posts. I'm having to scroll across the screen on every line. Thanks.

I was just about to do that and I realized a moderator did that for me, heh! Working on a new mold design today but not terribly happy with the 10 dollar price tag.

Ok, I made some adjustments to my original vision so that I could stay true to the title. The mold works great but because I was cheap the brick extraction is a bit tricky but considering you get a CEB for around 30 bucks I would say thats not too bad at all.



I put a board under to prevent the dirt from pushing the mold upwards. A slightly more expensive but better design I would make a plywood shell that fits inside the mold so that I can tap the shell out and preserve a perfectly formed block. I did not do this because if I would have to buy another plywood sheet which would add significantly to the original envisioned price of 30 dollars. Also due to price goals I did not purchase longer bolts which would have been more convenient because I could simply flip the mold over and tap the block out straight onto the patio. Because the bolts are shorter I have to tap the block out from the side which is more difficult.



I used my subsoil for the blocks which is mostly clay. The blocks produced were strong enough to support my weight (290lb 132kg) standing directly on top of them while shifting my feet around.

not bad...just cut a block slightly smaller than the CEB, press the block, set the mold over the block and push down...you might consider tapering the inside of the mold slightly..what patternmakers call "draft." then the block only has to move a couple milimeters before it releases.

are you using just clay? or a mixture?

when i was a snot nosed punk rugrat, we made a big batch of adobes, and added a quart or so of asphalt binder to each wheelbarrow full of adobe mix..used no straw at all...and we did not compress them..those were some strong blocks.

Yeah, I just updated my last post with some details you would be interested in. I used just clay for this block. The press works great for the CEB. It is really hard and great for landscaping or raised bed gardens. Also I could stabilize the block by adding some cement but I have some difficulty getting a homogenous mixture with cement and clay using my bear hands.

true..mixing is a chore. I have been tooling around looking at the briquette presses as this fits with taking the sawdust waste from my small sawmill and augmenting our heating some. no shortage of firewood here, but then there is no shortage of sawdust here either, or newspaper for that matter.
now, see, you can make yourself an horno, and press the briquettes to bake in it.

Warren David wrote:Could Amed, a moderator or admin edit the post that has the two photos that are next to each other so that they are stacked instead of side by side please? They are stretching the page on my laptop and making it very difficult to read the posts. I'm having to scroll across the screen on every line. Thanks.

Thanks to whoever it was that fixed the images.

Amedean Messan wrote:Ok, I made some adjustments to my original vision so that I could stay true to the title. The mold works great but because I was cheap the brick extraction is a bit tricky but considering you get a CEB for around 30 bucks I would say thats not too bad at all.

I like it. I have a son (12) who wants to experiment with bricks and building. This may be just what he needs.

Thanks, keep in mind though that you will need some leverage to generate enough pressure. I weight 290 lb so this is not a problem but a 12 year old will possibly not generate enough force - though I am unsure. Also consider spending a little extra to modify the mold so that the block can be extracted more easily. The extraction is the most difficult part because of the built up compression and can result in a percentage of defects which is why I would recommend a two layered system which enables the inside mold to be extracted intact.

Nice application of the press.
I read with interest some of the issues you are having with CEB. We have some of these same issues with biomass and I might make a couple of suggestions.
To get a good press of the material it helps a lot if the pressure on the plunger is applied directly to the center of the plunger. That will help the pressure to be applied evenly throughout the material. This is easily accomplished by adding a small block to the top of the plunger as shown in the picture.
Secondly, to meet your objective of low cost and to achieve a simple and easy ejection of the brick, try this. After compression just raise the mold a bit and set on a couple of rails as shown in the picture, then keep on pressing with the plunger to eject the brick. Make sure the rails are away from the opening at the bottom so as not to interfere with ejection.

See if this works...


Regards
Lee
EWB Cincinnati

Amedean Messan wrote:Thanks, keep in mind though that you will need some leverage to generate enough pressure. I weight 290 lb so this is not a problem but a 12 year old will possibly not generate enough force - though I am unsure. Also consider spending a little extra to modify the mold so that the block can be extracted more easily. The extraction is the most difficult part because of the built up compression and can result in a percentage of defects which is why I would recommend a two layered system which enables the inside mold to be extracted intact.

I was thinking I would have to add a third stage to the press.... and a platform for him to stand on

It would take some experimenting for us to get it right.

Amedean, if you make an extra press, send me an email, i will buy it from you. I figure i am about an hour or two north of you, so no problem coming to get it thanks

Hey Gary, what part of NC do you live in? I am studying for finals so I am busy right now but soon enough I will upload detailed instructions on a constructing a slightly more expensive but more functional design. I also plan to post a video of its operation. The design should be easy to construct so I feel a little guilty to ask for money and build one of these for you if your willing to make the drive. In other words I feel like the long drive would be just as difficult as making one of these but thank you for taking interest.

I wish to refine the design before I make any sales pitch. Currently the last aspect left is making an easier extraction of the block which. I have designed on paper but not yet constructed and tested the concept. Afterwards I will produce the financial report of the second design which should be no more than 50 dollars average without cost saving measures such as scavenging or deal shopping.

I agree with the problem to overcome being the extraction method. I would also love to see your design and video when your done with it. I tried to construct a CEB press using the Peterson Press design, and had the same problem with extracting the block. I may have not had the correct moisture content in the mix, so the test of the design is a bit inconclusive.

Funny, all these permaculture designs and ideas, and in the excitement, never can get a good, reliable, controlled test done. Always have trouble organizing proper experiments that can leave trustworthy data results. I know I'm not the only one who has this problem.

I have a very easy solution for super fast and simple mold extraction. All you need to do is line the mold with a long strip of thin plastic like the kind 2 liter bottles are made of. Bend the plastic into a rectangle shape the size of the inside of the mold and then fill with soil. Then just press out the finished block and peel away the plastic from the block.

Hey Bob, using a plastic liner will help with friction but I hypothesize I would experience a similar problem as before just a bit easier. Its not a bad idea but I want to make it in which the walls of the block are not subjected to shear stresses which is why I will produce the 2 layer design in a couple of weeks. I am burdened in study right now and also I got a Disney trip with the family in the next few days. I would say around 2 weeks I should have updated the thread with video and drawings.

Could you give the specs on the placement of the holes for the handle and press bar? Or anyone who has that information! thannks

Oh I need to apologize because I need to put in the updated CAD files where I have been slacking due to school/wife/kids/myself. I had a few flaws pop up with the above design. Specifically not to use 3/8 inch bolts like I did because they will bend under the stresses produced. I used 1/2 inch bolts on a smaller design which held up well so I guess to be on the safe side go for larger.

The hole on the top lever arm was an original idea for placement of a handle but after making a few dozen blocks I found it impractical and over-engineered. Also the bottom corners I would recommend using 4 bolts vs 2 bolts on each corner to prevent deformation. On the lever system itself use at least 1/2 inch bolts - the 3/8 inch ones WILL bend. The lever system is basically everything above the two corners I mentioned earlier so they will need the thicker bolts at the stress points.

Another thing, when you attach the arms make sure that they are vertical-most where the most stress is produced in compacting soil. This will alleviate stresses that would normally push the 4 vertical boards at angles.

If you are wondering, I used 2x6 boards and 2x2 for the arms. Surprisingly the 2x2 arms hold very well.

Ok I have partially built, what I need now I the placement of the holes for the lever and press bar. I've looked at the picture but I am unsure of their exact placement I am including pictures. I did use 1/2" carriage bolts as well, I also used wood glue on the frame

Not sure what the pictures went I attached them to my last post but they didn't show up

and

This might help till Amedean gets back to you. Very similar press.

http://home.fuse.net/engineering/biomass/Easy_BioPress_Micro_Compound_Lever_Press.pdf

I just stumbled onto this site/ thread. I too have been looking into CEB press designs. I was frustrated because the only plans or presses I would find were metal construction (CINVA/ GRAGO Ram) which I do not have the tools or the budget to put one of these together. That led me down the wood and bolts road as well. I am impressed with Amedean's design and all of the thread ideas and feedback. My goal is to build a ECO-Shed using sustainable building materials that I can use to teach my students (high school science teacher) about such concepts as sustainability - show them that there are 'other' ways of building/ living...

I had an idea for the form/ removal issue - see attachment

Basically you could use your initial design but only permanently bolt/ screw one end and one side piece together to forms two separate L pieces - these L pieces could have doll rod or something else to just line the form up and it could be held together by a heavy duty ratchet tie down - press brick - release ratchet - take apart form… This is assuming a ratchet could get the job done… but they are cheap in staying true to the design idea

Not sure if this is a good idea or what but I figured I would throw it into the mix...

Have we thought of cost Vs benefit?

I would imagine at times a short build time would be somewhat critical, say in an area that has a short dry season in which to build, or even conversely a short rainy season to provide the moisture to help with making the blocks stick together.

At what point does the cost or materials make it worth while to spend the money? As a former mechanic I had no problem spending 500 dollars on a specialty tool if it saved me 2 hours on a particular job, the ROI was usually a matter of a few weeks or maybe a month or two at the outside.

While I do like the idea of being able to build out of materials lying around, as they are usually cheap or free, the benefit of being able to crank out bricks at a much faster pace would pay for itself if you can find yourself doing other projects with the time, Sepp's use of excavation equipment while making a post and beam root cellar for example.

Anyway, the ratchet strap got me thinking about all of this, I would imagine it would work quite well in holding the two pieces together, but would be ungainly to attach and remove for every brick. There must be a rectangular beam that is the size necessary to make bricks. cut in 3-4 inch heights an 8 foot section would build a lot of CEB machines. and it solves the corner strength issue.

It still doesn't solve the ever present problem of getting the brick out of the mold, but I'll sleep on it and try to come up with something that works with the current design constraints.

my .02 cents, probably not even worth the good all copper ones either.

While not in the $30 range, any thought about taking a shop press, making a mold to fit it, and using that as a CEB press? What would be the complications?

Chris Geddings wrote:While not in the $30 range, any thought about taking a shop press, making a mold to fit it, and using that as a CEB press? What would be the complications?

Speed. This is MUCH faster, and enough pressure for the job at hand.

How about this for an extraction method. Make the mold with a slide-out removable bottom. Then, once the brick is made, slide the bottom and use the press to push it out. You'd want to raise the apparatus up high enough to allow the brick to clear and for you to fetch it out of there. You might get a little "squeeze leakage" in the brick there, but once they've dried a little, you can trim it off.

Also, I'd add a long steel bar (use brackets so you can remove it easily) to the end of the wood lever. You'll have to move the lever a longer distance, but the effort will be less. If you do this with a couple helpers -- one on on the lever, one operating the slide bottom and fetching finished bricks and one shoveling the mixture in, I bet you could have a respectable production rate, and the cost of the changes to the apparatus would not be too terribly much more. Might go from $30 to $60. Still quite a bit cheaper than the other options.

The use of a shop press is a great idea too. The shop press method will be much slower, but you will be able to apply several tons of force to make a much denser brick. Perhaps use a shop press to make bricks that need to have more strength, and the apparatus-made ones for lower-load duties.

I was thinking I would have to add a third stage to the press.... and a platform for him to stand on

It would take some experimenting for us to get it right.

Len, et al. To increase leverage on this device simply extend the length of the top lever. Increasing the distance between the effort and the fulcrum proportionately increases the force.

I've often wondered if you could rig one of those old bumper jacks to compress the bricks. Some people call them jack-alls. Seems you get a lot of leverage with those, and they are well made, especially the old ones. Easy to find, not too many people use them any more.

Connie Farmer wrote:I've often wondered if you could rig one of those old bumper jacks to compress the bricks. Some people call them jack-alls. Seems you get a lot of leverage with those, and they are well made, especially the old ones. Easy to find, not too many people use them any more.

I think you would get a lot more leverage with one of the designs being discussed above than with a hi-lift jack, which I think is what you're talking about. I've got one of those, and it's pretty darn handy, but the compound leverage involved in a CEB press makes them better suited to the job.

On your mold. Have you tried to line it with wax paper. Your bricks might not stick to much.
Just an idea.

The mold is a challenge but I have gained some experience and drawn a few conclusions. For starters, I want to avoid an over reliance on liners which disintegrate relatively quick because this would not be cost effective and they don't preserve the shape of the block. The good news is that I addressed the issue with a healthy degree of satisfaction by inserting plywood liners shaped to fit the bottom of the mold and additional liners along the sides of the inner walls. When your finished compressing you can simply turn the mold over and tap the block out. I made it in a way that the plywood liners absorbed the shear stresses from the friction while being tapping out from the bottom.

Ultimately the blocks still have to be stabilized in order to last. The test blocks I originally made are now disintegrated from countless rains except the stabilized ones. What I am happy in what I achieved is where I utilized a design that can be made out of wood for cheap to provide enough compression to make blocks. You can make blocks for example made out of hempcrete with this design. You can also make the press at any length for tremendous compressions, but you are limited to the strength of the mold, ability to extract the block and then the build material.

Also the design of the compound lever press I made initially can be made much better with some thought but the principle is the same. The mold will need to be fortified because a lot of compression will break. I like the idea of carving one right out of a segment of a tree trunk.

Amedean Messan wrote:Also the design of the compound lever press I made initially can be made much better with some thought but the principle is the same. The mold will need to be fortified because a lot of compression will break. I like the idea of carving one right out of a segment of a tree trunk.

using some harder wood for the mold might help out, too. if you're near a major port, dunnage made of extremely hard tropical hardwood can sometimes be found for cheap or free. good glue and simple joinery could be used to build an extremely durable mold.