Friday, April 28, 2017

Primitive Technology: Water powered hammer (Monjolo)




Published on Apr 28, 2017
I built a water powered hammer called a “Monjolo”. I started by making a water spout from half a hollow log to direct water from the creek. This was set up in the creek and water flowed through it. The hammer was made from a fallen tree. I cut it to size by burning it at the points I wanted it cut (to save effort chopping). Next I carved a trough in one end to catch falling water. This was done first with a stone chisel that was then hafted to an L–shaped handle and used as an adze. This adze only took about an hour to make as I already had the chisel head and cordage made of bark fibre to bind it with.
To save further effort carving I used hot coals from the fire to char the wood in the trough. I put the coals in using “chopsticks” (unused arrow shafts) to transfer them from the pit. The coals were fanned or blown with a wooden blowpipe till the wood in the trough burned. Then the char was scraped out. The sides of the trough were sealed with clay to make sure the wooden sides did not burn away which would effectively decrease the volume of the trough. This was approximately 8 hours work over two days.
With the trough carved I made a hole in the middle of the log as a pivot point. Using the same char and scrape method I burnt a hole right through the log using hot coals and a blow pipe. Again clay was used to prevent wood burning where it was wanted. To burn through the approximately 25 cm diameter log it took about 4 hours and 30 minutes. Another hole was burnt in the end to fit the wooden hammer head and it took a similar amount of time.
A tripod lashed with loya cane was set up at the water spout. The axel of the hammer was tied to one leg, the hammer fitted onto the axel and the other end of the axel tied to another leg. The trough was positioned under the waterspout to collect water and the tripod adjusted so that the resting point of the hammer was horizontal (so water wouldn’t prematurely spill out of the trough).
The trough filled with water, outweighed the hammer head and tilted the hammer up into the air. The water then emptied out of the trough (now slanting downwards) and the hammer then slammed down onto an anvil stone returning to its original position. The cycle then repeated at the approximate rate of one strike every 10 seconds. The hammer crushes small soft types of stone like sandstone or ochre. I carved a bowl into the anvil stone so that it would collect the powder. I then crushed old pottery (useful as grog for new pots) and charcoal. Practically speaking, this hammer worked ok as a proof of concept but I might adjust it or make a new one with a larger trough and bigger hammer for heavy duty work.
This is the first machine I’ve built using primitive technology that produces work without human effort. Falling water replaces human calories to perform a repetitive task. A permanent set up usually has a shed protecting the hammer and materials from the weather while the trough end sits outside under the spout. This type of hammer is used to pulverise grain into flour and I thought I might use one to mill dry cassava chips into flour when the garden matures. This device has also been used to crush clay for porcelain production. A stone head might make it useful as a stamp mill for crushing ores to powder. It might pulp fibres for paper even.

Sunday, April 23, 2017

Making Ciabatta Bread






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Ciabatta Recipe

Biga:

Ingredients

3/4 teaspoon dry yeast (I use instant yeast)
1 3/4 cups of cold water
3 1/2 cups all purpose flour (470 grams)

Directions

1. If you are not using instant yeast you should soften the yeast in 1/2 cup of the water first.
2. Mix all ingredients together into a wet batter/dough.
3. Cover and refrigerate for 24 hours.
4. Can be stored in the refrigerator for up to two weeks.

Ciabatta:

Ingredients

1/2 teaspoon dry yeast (1.5 grams)
2 1/2 tablespoons of warm milk (38 grams)
1/2 cup plus 1 1/2 tablespoons of room temperature water. (143 grams)
1/2 tablespoon of olive oil (7.5 grams)
1 very full cup of Biga (250 grams)
2 cups less 2 tablespoons of all purpose flour (250 grams)
1/2 tablespoon salt (7.5 grams)

Directions

1. Stir the yeast into the milk in the bowl. Let stand for 10 minutes. (Not necessary, to let it stand, if you are using instant yeast.) This will work much better if you use weights rather than dry measures. Add the water oil and the Biga, mix until blended. (Use the Paddle if you are using a stand mixer.) Mix the flour and salt together and add to the bowl mix 2 to 3 minutes with the paddle then switch to the dough hook and mix for 3 minutes at low speed then 3 minutes at medium speed. The dough will be very sticky. Turn it out onto a well floured surface and knead briefly adding as little flour as possible. ( A trick that works, if you wet your hand the dough won't stick to them) The dough should start to be less sticky and become smooth and springy.
2. Place the dough in an oiled bowl or air tight container. Let it rise for 1.5 hours at room temperature. (Room temperature is important, not in a warmer area or prover.) After this time the dough should be full of large bubbles.
3. Turn the dough out onto a generously floured board/counter. Cut it into two loaves roughly the same size. Shape each into a cylinder about 10X4 inches, pulling gently to get each loaf about the same size.
4. Place each loaf on a generously floured peel, parchment paper or the back of a cookie tray. Dimple each deeply with your fingers to prevent them from rising too much. Sprinkle the tops generously with flour and cover with a towel and let rise at room temperature for 1.5 to 2 hours.
5. Half hour before baking preheat the oven and a baking stone to 425F.
6. Carefully turn the loaves onto the stone. I bake mine separate the first loaf at 1.5 hours of rising and the second one at 2 hours. The loaf should bake for 20 to 25 minutes and during the first 10 minutes spray water 3 times in the oven being careful to not spray any directly on your baking stone.
7. Cool the loaves before cutting them.

Friday, March 24, 2017

Primitive Technology: Termite clay kiln & pottery




Published on Mar 24, 2017
I built this pottery kiln and some pottery from termite mound clay to test an alternative clay source to my usual one from the creek bank. I started by making a large grate from ordinary clay. It was just under 50 cm in diameter. Next, I took dry chunks of termite nest and put them into the pit in front of the tiled roof hut. The chunks were crushed and water was added to slake the clay. The clay was trodden on to mix it. Dead palm fronds were added to the clay to stop it from cracking as it dried and to add insulation to the kiln. The mixture was trodden on again and then taken from the pit. A trench was dug to form the firebox of the kiln and a wall of clay was made in the front of the trench. A hole was dug into the wall to allow air flow into the firebox.
The grate was placed on top of the firebox and the walls of the ware chamber were built around the grate. When the kiln walls were finished, grate bars made from termite clay were placed into the firebox. Grate bars are important for fireboxes as they lift the firewood off the ground allowing air to move up through the fuel bed for more efficient combustion. Burning wood as a heap on the ground allows cold air to flow up and over the coals, cooling the kiln and leaving the air unreacted with the fire wood. It still works but is much less efficient than using grate bars. The finished kiln was 50 cm tall (above grate height), 50 cm in diameter and with walls about 12.5 cm thick. The pit/firebox was about 25 cm deep and 25 cm wide with grate bars sitting half way between the ground and the circular kiln grate above.
Next, for the pottery clay, I selected a termite mound built on red clay soil. I took it to the kiln area and slaked it with water and mixed it in a small pit. I crushed up an old grate from a previous kiln and mixed it into the termite clay as grog. Grog prevents pottery from cracking as it dries and helps prevent breakage when firing. I then shaped the clay into a small urn. I also made some barrel roof tiles and a smaller pot from termite clay. I then stacked the kiln with the termite pottery.
To fire the pottery, I collected a large pile of dead wood and started a fire in the firebox. I heard some explosions in the kiln early on and knew something broke but continued anyway. Within an hour the kiln had heated up well and the pottery was glowing red hot. By the second hour the temperature went down illustrating an important point: if you over fill the firebox with wood the kiln will choke it and not burn efficiently. Realising this mistake I merely let the wood burn down a little so more air could get through. By 2 hours and 30 minutes the kiln was firing nicely again with all the pottery glowing low orange (about 845 c or 1550 f). I kept it at this low firing temperature for another 30 minutes. The whole firing process took about 3 hours from start to finish, a relatively short period of time for firing pottery.
When I took the pottery out, one tile had broken and the urn had spalled (a piece of the outer pot broke off) possibly due to still having moisture in it. The urn was still useable though and I use it to water the cassava patch. The forge blower was well fired and is now immune to water damage, no longer needing to be carefully protected from the rain. I put it in the barrel tile shed for storage. I put the broken tile and spalled piece from the urn in a special heap of broken pottery. When I make pottery in future I can crush up these broken pots and mix it into the new clay as grog to strengthen the new ceramic items. Finally, I stored the good tiles at the barrel tiled hut as replacements for broken tiles in that structure should there be any damage in future.
Termite clay is good material for making furnaces and an OK substitute for good pottery clay should it be difficult to find a better source. The termites have already processed the clay by the fact that their mouths are too small to include sticks and pebbles into their structures. As a result, the clay is very smooth and plastic. Too smooth for my liking, in fact, I’m used to working with coarser clay that has silt mixed into it naturally. I find that termite clay is either too runny when wet or cracks too easily when drier. It was difficult to form into complex shapes and it took me 2 attempts to make the urn. But for forming objects like tiles it’s OK, it can be pressed into shape and it will hold without difficulty. In future, I’d be likely to use termite clay for mass producing formed objects such as bricks, tiles, simple pots (formed over a mould) and possibly pipes, thereby conserving the dwindling clay supply from the creek bank which I’ll save for more intricate pottery. In summary, termite clay is able to be used to produce basic pottery if no other source can be found. If you have a termite nest you can make basic pottery from it.