Making Adobe Bricks

By Duane Newcomb
Published on March 1, 1981
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With this apparatus you can conduct a simple compression test.
With this apparatus you can conduct a simple compression test.
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Adobe is an economical building material to use in almost any environment. 
Adobe is an economical building material to use in almost any environment. 
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Place your adobe brick mold on newspaper.
Place your adobe brick mold on newspaper.
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You can perform a fairly accurate soil test by filling a jar with 1/3 earth and 2/3 water. Then shake the jar and let it settle overnight. In the morning, measure the thickness of the layers.
You can perform a fairly accurate soil test by filling a jar with 1/3 earth and 2/3 water. Then shake the jar and let it settle overnight. In the morning, measure the thickness of the layers.
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Cover the curing bricks to prevent cracking from rapid drying.
Cover the curing bricks to prevent cracking from rapid drying.
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Two possible mold designs for making adobe bricks.
Two possible mold designs for making adobe bricks.
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Then fill the form with the mud mixture and cover it with more newspapers.
Then fill the form with the mud mixture and cover it with more newspapers.

The following excerpt from The Owner Built Adobe House by Duane Newcomb is from chapter three, “Making Adobe Bricks,” and is reprinted with the permission of the author.


Modern adobe bricks consist of a mixture of clay, sand, straw, and emulsified asphalt.

Clay holds your bricks together just like the cement in a concrete block. It contains primarily an aluminum salt and is made up of extremely fine particles. There are several different kinds of clay, but you can use any one of them for making bricks. The so-called adobe soil of the Southwest actually contains too much clay to produce good bricks. What you need is a sandy clay or a clay loam. Soil with too much clay produces too many shrinkage cracks. Soil that is too sandy crumbles easily. If, after a soil test you find that your ground has too much or too little clay, you can bring in sand or soil with a higher clay content as needed.

Sand, the second ingredient used in making adobe bricks, actually is an inert filler held together by clay, much like gravel in concrete. You can use almost any type of sand in making bricks except beach sand, which contains too much salt. Add extra sand to your soil only when you need to lower the clay content to meet code requirements.

Straw, the third ingredient, doesn’t add strength but binds a brick together and allows it to shrink without cracking.

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