Monday, May 26, 2008

How to make a CEB

You start with dirt. It turns out the best quality dirt for making CEBs at our site is a clay layer about a foot thick located just under the topsoil. If you go deeper, the soil becomes too sandy. It's really great soil for growing things - and hardly any rocks - but not as good as the clay for making CEBs. You want the clayish soil to be fairly dry.

Next you break out the sand and Portland Cement to mix with the soil. Cement is about 5-8% by volume, the sand is added to help get the right consistency for the whole mix.

Then you put them all into the mixer according to the recipe. Once thoroughly mixed, the mixing bowl is tipped over and dumped out on the ground where it can be scooped into 5 gallon buckets.

The buckets are then carried to the hopper of the Green Machine, where they're dumped through a coarse screen into the brick-making area. The machine does the rest automatically, pressing out a brick in about 10 to 15 seconds and pushing it out onto the conveyor belt where they can be taken and stacked to cure. They cure best if they're damp, so they're sprayed down and covered with plastic. For now, they're just stacked on the ground. Once the foundation and first floor deck are finished, they'll go straight from the machine onto the wall where they'll cure. They become pretty hard with in two hours, but Wayne likes to give them a full week to really set up completely.

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