Primitive Technology: Lime
13,165,229
Published 2018-03-06
In my local geography, calcareous rocks such as limestone are absent leading to a difficulty in acquiring the feed stock for lime making. However, I was still able to make lime by collecting the shells of large terrestrial snails that are native to the rainforest here. The unoccupied shells of these snails were gathered up and stored at the hut. Fire wood was gathered and packed neatly into the kiln. Importantly, the firewood was stacked on top of the grate rather than underneath it in the firebox as is the normal procedure for firing pottery. Using an ordinary updraft pottery kiln in this configuration allows it to reach much higher temperatures than would be possible during normal use. The wood was lit from above and the fire burned down towards the grate. Alternate layers of shells and wood were added on to this burning fuel bed. After adding the last layer of wood to act as a “lid” to prevent heat loss from above I left the kiln to finish on its own, unsupervised. The whole process took about an hour and a half.
When the kiln had cooled down a few hours later, I took out the calcined shells. Not shown in the video was the fact that some shells got so hot, the dirt stuck to them turned into slag and fused to them, possibly with the lime acting a flux lowering its melting point. This extreme heat (+1200 c) should be avoided as the over burnt lime becomes “dead lime”, unable to slake in water. Most shells were still useable though. They were taken out of the kiln and had water added to them. An exothermic reaction then ensued. Heat was produced as the lime quicklime turned into slaked lime. The water heated up creating steam and the shells decomposed into a white paste. The paste was stirred and crushed pottery was added to it as an aggregate (sand is normally used for this, I just had a lot of old pot sherds lying about to dispose of). This lime mortar mixture was then formed into a block shape and left to dry. It took about a week and a half to set as we have had extremely humid, wet weather. The block was observed to have set demonstrating its properties.
What I created is actually lime mortar, typically used for mortaring bricks and tiles together. It’s basically the ‘Glue’ that holds together the building blocks of masonry structures. From my research 20 kg of lime mortar is used on a 1 m square section of brick wall. 5 kg of lime to 15 kg of aggregate (sand, grog etc.) per a 1 m square section of bricks. The shells, though large, are not terribly abundant. A method for finding shells efficiently needs to be made before considering making lime mortar in this fashion. From my experience sand bars in a creek sometimes accumulate snail shells from higher up in the mountains. In these spots, water velocity decreases and shells in the water tend to drop out of the water column. Additionally lime may be partially replaced with ordinary wood ash in mortar without a corresponding decrease in strength. To conclude, making lime in a land without limestone is possible but can be problematic when trying to do so on a large scale.
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All Comments (20)
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just in case no one knows, if you turn on closed captions, he tells you what's going on... for some reason it changes my experience.
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"hot shell fragments shooting out of the kiln causing annoyance" this is why I love this channel
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Btw - For anyone at home: You don't want to touch the burnt shells with your bare hands as they will react chemically with the moisture and the protective oils on your hands. Lime is a strong base (alkaline) called Calcium hydroxide which is similar to drain cleaner pellets in strength
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"Making lime from snail shells" was new knowledge for me. Thank you. The mortar you made is in Turkey; It is called "Horasan Mortar" or "Roman Mortar". It has various formulas and egg white can also be mixed into it. This mortar has been used in archaeological structures for thousands of years and is a stronger type of mortar than concrete. Over the years it gets harder and becomes just like a rock. However, although it is hard, its biggest feature is that it absorbs the impacts that occur during earthquakes.
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He gained 7 million subscribers without talking and just pure content. What an amazing guy.
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So a long time ago, some guy saw a snail shell and said, "Hey, we can reinforce our castles with this."
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This guy's doing chemistry with sticks and mud better than I could do with an entire lab at my disposal.
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After watching your videos, I tried to build a furnace in the Appalachian mountains where I frequently camp for two weeks at a time. As you can imagine, there are plenty of woods, and the terrain contains many sizable stones, but even with river access there is little mud or clay. If at all, it is tightly bound between the roots of trees. The main materials there are rock, sand, gravel, wood and water. Thus, i modified the design to a stone furnace with the sparse amount of clay-rich mud as mortar. Got pretty hot, but not quite hot enough to fire the little bit of clay I found. I would definitely try again next spring
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Guys, don't forget to turn on subtitles/captions! Thats how he communicates with us.
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REMINDER! Turn on your subtitles to discover the magic!
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My headcanon for Dr. Stone is that Senku binge watched this guy to learn survival skills.
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3:05 oh wow, some cool aerial shots of Australia, you're too generous
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Next on Primitive Technology: Colonizing Mars
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This guy is more entertaining than anything "trending"
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A thousand years from now, some archaeologist is gonna dig plot out and be hella confused
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every dude: starts the engine of his car in the morning this dude: starts fire in his furnace in the morning
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As the old saying goes, When life gives you snails, make limestone
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So you can make lime where there is no limestone, but at a snails pace.
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Dr. Stone! Right on the money!
