Primitive Technology: Wood Ash Cement

Primitive Technology: Wood Ash Cement


Eucalyptus tree (any tree will do) Fallen bark and leaves The kiln Hot coals Burning a lot of material for its ash Ash falls through grate Fine white ash with nearly no charcoal in it Adding ash to water Stir well Tip off excess water containing potash Retain the paste which contains the insoluble calcium hydroxide and calcium carbonate Compress into pellet Take it to the forge (a kiln would also do on a larger scale) Heat the pellet to an orange heat Extract the pellet and let it cool Slake pellet in water Stir Crush up old terracotta tiles (from previous project) Add terracotta as aggregate (sand or gravel may also work though I’ve only tested this type) Form into shape Here’s one I prepared 3 days earlier It has set hard Most importantly it will not dissolve in water Wood ash cement

100 thoughts on “Primitive Technology: Wood Ash Cement

  1. I think I have the chemistry right. If any chemists are watching correct me if I'm wrong. The calcium compounds are converted to calcium oxide in the second firing, turn to calcium hydroxide in the water and then set to calcium carbonate in the air. There maybe a pozzolanic effect due to the alumina and silica in the ash too. The end product is a cube made only from wood ash (fired twice) and crushed pottery. It sets hard after 3 days and will not dissolve in water even when fully submerged for 24 hours. Thanks.

  2. This channel feels like cultural appropriation but then it seems racist to say a channel about primitive technology does not include caucasians. Not sure what to make of all this PC stuff.

  3. и нахрена я цемент покупаю? столько золы за зиму выкидываю.

  4. I seen on discovery Channel nearly 20yrs ago, the romans pretty much used this same method. Thanks for the video

  5. Hey man, could I suggest a potentially interesting project for you to try? What if you can build a scale. Definitely not to determine if someone is a witch, but to standardise mixtures of stuff. Maybe create your own standard weight. Surely, youre not going to do physics looking for secrets of the universe. No need to worry about milligrams worth or weight change every hundred years or something. I wonder what would be the basis of your unit. Could it be weight of food for an average meal? A potato? Optimum weight for throwing stone? idk

  6. the deception, the person does not behave naturally. All the time posing for the camera, Yes, hands shaking, but it's easy to do just a push-up from the floor. He's got too many layers of fat for the person leading a secluded life, and survival

  7. pretty good though wood ash does have quite a few other minerals in it which are fine but not great for cement, try lime and clay ground finely then kilned together then ground up can be mixed with slaked lime to make it go further and maybe even a touch of gypsum too to control cure and you would have something pretty close to Portland cement. You could even use the same kiln method and throw lime and clay powder into the fire.

  8. If any one already asked some one point me to the answer but what the durability of these things? Did you call the myth busters to blow it up?

  9. Hi, I recently tried to reproduce this experiment, however I had not refined the charcoal out with water, when i fired the ball of ash and quenched it, the ash turned blue/green and smells of sulphur, so not really sure what I did…

    Aside from not having removed the charcoal, other differences include used a slow combustion heater ash and fire, the wood burnt was primarily eucalyptus logs.

    Anyway, interested to know if anyone knows what I did.

  10. As someone who builds concrete walls and foundations, this really inspires me. Ive wanted to figure out an alternative for doing footings using natural materials, as well as building earthship type structures and something akin to this is what I'm leaning towards. It would take tons of prep, but I live in the wealthy side of the Appalachian mountains and the bougie hippies might be willling to foot the bill. Thank you Primitive Technology!

  11. I really wanted to try this for some time now and never got around to it until tonight 09/05/19. My son had a school project to make a brick from clay and he didn't tell me until last freakin night!😒 so i used what i had… Charcoal ash that i had plenty of from barbecuing out a small $20 grill.. Lighter fluid.. A hammer.. A kid.. 😆 Water of course and backyard stones.. I filled a flower vase up 3/4 full, added the ash until its consistency was like mud.. I had rock dust from my son crushing stones with the hammer into fine pieces.. I then grabbed 3 hand fulls of the ash mixture and mixed it with the stone dust.. Until its was formable and stiffer because of the rocks.. I then threw it on the grill.. Where i currently have been waiting for about 45 minutes to an hour its 8:23pm.. I moved them from the top rack and put them inside with the burning embers.. When i picked them up with two sticks.. They were nice and hard.. Lol wish me Luck

  12. So if I'm getting this right

    Take white wood Ash
    Soak it in water to clean it
    Fire it again
    Put it in water again
    Mix in powdered terracotta (I think that's what it's called)
    Possibly fire it again (or it just dries on its own, wasn't too clear on that part)
    And you essentially have concrete, ready for use in some form of brick, or floor

  13. Maybe if you fire the bricks from your recent adode wall video you can use this cement as grout? I'm not a contractor though so i have no idea if that would work.

  14. So lesson learned: Step 1. Make That Ash and wait a while for it to be perfect
    2. Grab that Fine White Ash not mixed just White Ash
    3. Put that ash on your water but not to much
    4. Make a paste obv what else would i be talking about?

  15. Fine video. Only one thing I would have not done. That is, poring off the (Potassium) as waste. (Potassium) is a very useful product. You could use it for soap making and an electrolyte for battery making. Also as a fertilizer in your garden. Many more uses than what I just mentioned. Thank you for your time showing me and the entire world your skills.

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