Wednesday, March 28, 2012

Making production clay bricks by hand.

(It will take some months to finish this post, I dont have pics of all the process.)

This is how we are currently making clay bricks. We use clay from our site , add 40% volcanic sand, mix, mould, dry, stack kiln, burn with waste charcoal dust, cool, stack outside for sale.

Getting the clay.

Volcanic Sand.

Mixing the clay and sand.

These guys are strong and fit. In square pits the mix clay and sand 60/40%. They add water and mix with their feet like grape wine making. We let it sit a day, then mix again.
The brick mould is metal with 4 partitions. It is cleaned in the sink to the left. There is a board underneath.

they know pretty exactly how much to put in the moulds with shovels.
He presses the mixture into the moulds

thens smoothens it out and removes excess or adds it not enough.

Erasto carries the mould onto the cement floor and flipped over nesxt to the last one.

the plate is slid off the top and the either smoothed with a board or their hands.then the mould is lifted straight up. We get a slight variation on brick thickness, 1-3 mm difference. When building the bricks should be laid upside down to how they were stamped out.

The bricks are let to dry for 1-2 days. A good moulder can do 400-600 bricks a day. It is piece work .
Once they are stiff they scrap off any lip on the brick cornors on the bottom and stand the brick up for 2-3 days to dry faster.

then the bricks are stacked up to the ceiling for 3-5 weeks of drying.

As they become dry we stack the kiln. The kiln has 6 tunnels. Some years ago they were left open and logs were pushed in for 3-4 days to burn the bricks. Firewood is expensive, scarce, and unethical. So we learned to burn using waste charcoal dust. Most of the tunnels are filled with charcoal bricks we make. they are stacked loose. In the first few courses we put these same charcoal bricks about 1/6. after course 10 we sprinkle the dust on top of each course.. Bricks are stacked loosely. We put in 24 courses, about 3.5 meters high.

a later of old reject bricks is packed tightly over the whole kiln as insullation.


We start the kiln with firewood in the morning. we brick up the openings by noon.
second day we add some more wood. then the charcoal burns it way slowly in the next 3-4 days.

after burning and cooling we have to remove the bricks and stack outside. Dust work. They have masks but mostly choose not to wear.

this particular burning something happened and 1/3 of the bricks are under burnt. useable but not top quality.

Hussein is carrying 18 bricks. 54kgs or 120lbs. Each person removes and stacks 1000 bricks per day.
Broken bricks . Some are useable some are now rubble.
The kiln is x . Rainwater is caught off the roof. The bricks on top of the wall are used later to cover the kiln as insulation.


  1. Thanks Erik! I would love to do that with you guys...remeber that bucket list? Payback I guess.......

    1. In swahili we say "pole!"

      It is going to take awhile to finish this one. Keep coming back.

  2. Nice post. I am currently without a kiln to make brick and tile. I hope to construct a new one sometime this new year. Not a big as yours, but the same type but with wood as it is plentyful and cheap here. You blog is inpirational to me thanks!

  3. Just read this post Erik. What a great read, and thanks for all the pictures. I've never seen a brick burn before but I would love to.

    I've often used reclaimed brick and sometimes as I'm installing them I think about how many human hands have touched those bricks. Probably 10 or more by the time they first went into the wall, then another 5 to get it off the wall and delivered to me and another 3 to get it up the scaffold and back into a new wall.

    The life of a brick is an incredible thing

    1. thanks Sean, Now I have more motivation to finish it. I have more pictures of the other parts.

      You got me thinking about stamping our bricks with our name. maybe in another 50 years people will be demolishing buildings built with our bricks and be curious where they came from.

      maybe 8-10 touchings of a brick until it leaves our yard.

    2. Hi Erick! Kindly I appreciate your posts, really they are quite educative and informative.Please can you sent me your e-mail. I am planning to establish Clay Brick factory in a near future. Currently I am looking for a business partner to discuss about the project.

    3. My e-mail:

  4. It's always wonderful to look at brickworks. There is apparently a way of making bricks that doesn't involve heat, or nearly as much heat: geopolymers. A class of concrete that is made of aluminum and silicon polymer chains. The old roman cements which have lasted two thousand years and have rarely been chemically replicated -- these are geopolymers based on volcanic ash. If you have volcanic ash where you are, that's the primary cost in places without it -- also called a pozzolan. There's a lot of internet material on geopolymers but not many clear formulas -- I've scraped through hundreds of pages of scientific literature and made a list of a few formulas worth trying. Davidovits is the French scientist who coined the word "geopolymer", but he's a horribly long-winded speaker and hides his formulas. He has spoken about making geopolymers from volcanic soils in east Africa.

    == Davidotas video formula ==

    Dry ingredients:
    - large pile of crumbly fossil-rich kaolin-poor limestone (from France)
    - lime (hydrated lime)
    - natron (from France)
    - kaolin clay (or any pozzolan, like volcanic ash)

    - Roughly 1 cubic yard (1 ton) limestone aggregate
    - Roughly 1 cubic foot kaolin
    - Roughly .5 cubic foot natron and hydrated lime
    - 130 gallons of water

    Rough ratio:
    27 : 1 : 0.5 : 17 ... limestone:kaolin:natron+lime:water

    # Measure out water
    # Pour in natron and hydrated lime
    # Pour in kaolin
    # Mix to yield white milky fluid
    # Pour in limestone aggregate
    # Mix thoroughly
    # Let sit several days in full sun, French Mediterranean summer
    # Excess water evaporates
    # Yields friable "disagglomerated" material like moist lumpy sand
    # Note: looks nothing like a "slurry" at this point

    This is said to be:
    - 95% limestone aggregates
    - 5% rock-making binder
    - 12-17% water content, consistency of wet sand

    # Set up wooden form with volume roughly one-half cubic yard
    # Pack crumbly moist cement into form with rammer
    # Remove mold 4 hours later

  5. Replies
    1. Justin - learn to be a human, be polite, help, build. Instead you hide behind that big flag.

    2. Wow. I just spent four hours reading all of Erik's posts. I've got no problem with his writing and spelling. Juistin Thompson; as an American I'm embarassed for you and because of you. YOU are part of the reason why non-Americans hate Americans. Additionally, if you are going to criticise someone's language abilities and grammer, I wouldn't make so many mistakes yourself. Maybe write whole sentences, with punctuation. What a creep. Erik; don't pay that fool any mind. I love your posts and wht you are doing. Keep it up. Beautiful work and great information. Thanks!

    3. Wow Anonymous. Thanks for reading! Special thanks for commenting. I always meant to come back and edit but time is limited isn't it.

  6. hi erick am in kenya and would love to have bricks that have really sharp edges after burning..sipendi kama zimevunjika vunjika kando. meanwhile the only way nimepata ni compression machines

  7. Hata mimi sipendi kama zimevunjika kando. Lakini pia sipendi kama ziko za mashine. nataka ionekana natural. you can make almost perfect if you slow down and make them much drier and one at a time. however the cost would go up. my bricks are already expensive. I seem to be getting a bigger market for facing bricks. email erikrowberg - remove - add @

  8. Sasa erick weww vile umeishi kwa wazungu kigodo.. hizo bricks zao hua very good, ukiona the way the look is soo good. Uniformly red, zina smooth surfaces na very sharp edges. Whats there secret?
    Talking of making bricks much drier what do you mean?

    1. Hawa wana tengeneza na extruder machine, zinakatwa na piano wire. Lakini ulaya wana tafuta handmade sana na ina bei kubwa zaidi.
      making drier means adding less water so they hold shape better. Tuhame email.

  9. Nishakutumia mail

  10. Mbona hawapendi hizo za extruder??

  11. Volcanic Sand used in Construction
    Tanzania is taking advantage of its natural resources, using volcanic ash as part of the creation of their clay bricks. Each brick consisting of up to 40% of volcanic ash, this is then mixed and molded with waste charcoal dust, and then stacked outside to cool.
    The process is definitely hard labor, from the mixing 60-40 mixing process, that is usually mixed by stomping on this mixture, much like stomping on grapes for wine, and then placed in metal moulds that can create 4 bricks on each metal mould. Experienced brick-makers have a high level of accuracy when it comes to the proper placement and mix, as they have been doing this for years. As they are cooled outside, they also are placed in order, not sticking to each other, or that would make it a faulty brick. It takes up to 2 days for the bricks to cool down and then stacked for another 3-5 weeks for drying.

  12. This is great
    Is there anyone who can tell me of best places to get suitable clay in Tanzaniq, Niko Dar

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