Forge Blower

I invented the Bow Blower, a combination of the bow drill and forge blower to make a device that can force air into a fire while being easy to construct from commonly occurring natural materials using only primitive technology. I began by fanning a fire with a piece of bark to increase its temperature. It is this basic principle I improved on throughout the project.

Next, I made a rotary fan from two pieces of bark that slot together at right angles to each other to form a simple 4 bladed paddle wheel about 20 cm in diameter and 5 cm tall. The blades of the fan were not angled and were designed only to throw air outwards away from the axle when spun. The rotor of the fan was made by splitting a stick two ways so it formed 4 prongs. The fan was then inserted into the prongs and the end lashed to hold it in place. Spinning the fan rotor back and forth between the palms of the hands fanned the fire. But only some of the wind generated by the fan reached the fire. The rest of it was blowing in other directions, effectively being wasted.

So I built a fan housing from unfired clay to direct the air flow into the fire. This was basically an upturned pot with a hole in the top, a spout coming out of the side. The housing was about 25 cm wide and 8 cm tall. The hole in the top and the spout were both about 6 cm in diameter so that the air coming in roughly equalled the air coming out. The base of the fan rotor sat in a wooden socket placed in the ground to make it spin easier and the top of the rotor protruded from the hole in the top of the housing.

Now when the fan spun, air entered the hole in the top of the housing and exited the spout in the side. Importantly, it doesn’t matter which way the fan spins, air always goes into the inlet and out the spout. Air is thrown out towards the walls of the housing and can only leave through the spout while the vacuum in the centre sucks new air into the housing through the inlet. A separate clay pipe called a tuyere was made to fit over the spout to direct air into the coals. This was done because the pipe that touches the fire can melt away so it’s better to make this part replaceable.

Instead of making a large wheel and belt assembly to step up the speed of rotation, I opted for a 75 cm long bow. I made a frame to hold the rotor in place consisting of two stakes hammered into the ground with a socketed cross bar lashed on to hold the top of the rotor. I made bark fibre cordage and tied the end to a stick. I then looped the cord around the rotor and held the other end in the same hand holding the stick. I then pushed and pulled the bow causing the rotor to spin rapidly, forcing air into the fire.

I made a simple mud furnace for the blower. Then I collected orange iron bacteria from the creek (iron oxide), mixed it with charcoal powder (carbon to reduce oxide to metal) and wood ash (flux to lower the meting point) and formed it into a cylindrical brick. I filled the furnace with charcoal, put the ore brick in and commenced firing. The ore brick melted and produced slag with tiny, 1mm sized specs of iron through it. My intent was not so much to make iron but to show that the furnace can reach a fairly high temperature using this blower. A taller furnace called a bloomery was generally used in ancient times to produce usable quantities of iron and consumed more charcoal, ore and labour.

This device produces a blast of air with each stroke of the bow regardless of whether it is pushed or pulled. The bow makes it possible to operate the blower without using a complicated belt and wheel assembly used in traditional forge blowers. There is a brief pause at the end of each stroke where the fan stops to rotate in the other direction, but this is effectively no different to the intermittent blast of a double acting bellows of Europe or box bellows of Asia. The materials used (wood, bark, bark fibre and clay) are readily available on most continents.  No leather, valves or precisely fitted piston gaskets are required as with other types of bellows. The cords for this device wear out often so a number of back up cords should be kept handy for quick replacement. In summary, this is an easy to make device that solves the problem of supplying forced combustion air required for high temperature furnaces and forges.

 

 

Grass Hut

 

I built this grass hut up on a ridge. It’s roughly parallel with the tiled hut and wattle and daub hut that are a couple of hundred meters away down in a valley. I built it on a ridge to get away from mosquitoes in wet weather. This project took 7 days to make. I looked for a spot and cleared it on the first day, built the frame on the second, and spent the next 5 collecting grass. Grass is difficult to collect in this dry forest and I had to climb further into the mountain to get it.
The design is a simple pointed dome that’s easy to build. The tools used were simply sharp stones and a digging stick. It’s 2.5 m wide and 2 m tall. 8 lawyer cane strips were driven into the ground to form the ribs of the structure and hoops of cane were put over this to attach the grass to. Vine was used to tie the frame together and to tie handfuls of long grass to it. When the hut was almost finished a cap was made and lifted onto the top of the dome to finish it.
This hut is easy to build and houses a large volume. The shape is wind resistant and strong for it’s materials. Gaps can be seen in the thatch but not if viewing from directly underneath meaning that it should shed rain well. A fire should be possible in the hut as long as it’s small and kept in a pit in the center.The reason the hut took so long is due to the scarcity of grass on the hill. It could be built much quicker in a field.

Sweet potato patch

I built a fenced enclosure and cultivated sweet potatoes (from civilisation) and yams (from the wild) in it. I originally had a small 3X3 m garden behind the wattle and daub hut that already had some sweet potato and yam vines growing in it that were planted after the hut was built. But wallabies kept eating the leaves. So I made a wattle enclosure around it to keep them out.  Wood ash was added to the soil to provide potassium and phosphorus for the growing tubers.

The previous small garden was organised in rows (not seen in this video) but this was hard to water during dry weather. So I re-organised the patch into 1 meter wide mounds with pits in the centre. Vines were planted into the mounds and water poured into the centre of each mound watered the vines. So then I had a small garden with 9 mounds contained within it. I decided to enlarge the patch to fit in more mounds so I took out 2 sides of the fence and extended them by a meter each. So the patch ended up being 4X4m and contained 16 mounds. In addition to wood ash, leaf mould was added to the mounds for fertility and to reduce loss of moisture.

The patch, being in the dark forest understory, received only about 2-3 hours of direct sunlight per day so the yield was disappointingly small. Nevertheless, the patch produced a few small sweet potatoes and a single larger yam. I also picked some green growing tips of the sweet potato vine that can also be eaten. I boiled the greens slightly in a pot with a hot stone and ate the leaves. I then roasted the sweet potatoes and yam in the coals of the fire. The sweet potatoes (purple fleshed tuber) taste sweet and starchy whereas the yam (white fleshed tuber) tastes similar to an ordinary potato. After eating, I took the wood ash from the fire and poured it back into the mounds that were harvested, replanted them and watered them. In future I’d plant the sweet potatoes in an area that receives much more sunlight in order to dramatically increase production. I’ve grown the same variety at home and it produces a much greater quantity and size of tubers in full sun. Wood ash also tends to increase tuber yield and so is a good use for waste ash.

The sweet potato is a remarkable plant. It’s a staple food of many traditional cultures. NASA has considered it a potential crop to be grown on spaceships for long term missions. In terms of energy production it’s only 3rd behind sugar cane and cassava. It produces the most food value (a combination of edible energy and nutrition) of any crop per unit space and time. A study of Fijian farms using manual labour showed that ratio of energy put into farming vs yield of energy was 1:17 for rice and 1:60 for sweet potato.  It grows on marginal soil and doesn’t require much nitrogen to grow. It takes a relatively short growth period of 3-4 months to yield. All parts of the plant can be eaten including the leaves which provide additional protein and nutrients.  I grow the purple variety (because it tastes better in my opinion) but all varieties are nutritious and will stave off malnutrition. A person could potentially be nearly self-sufficient from a small plot of sweet potatoes. Note that in colder climates, regular potatoes could be grown instead of sweet potatoes.

 

 

Weaving bark fibre

Woven Bark Fiber

I made a rough type of textile from bark fiber. This is the same tree I use for making cordage though I don’t know its name. It has been raining a lot here lately (the video also shows how well the hut stands up to rain) and this caused a large wattle tree to fall down taking a few smaller trees with it. One of the trees was the type I use for fiber. So I stripped the bark from it and divided it into thinner strips back at the hut.

I spun the fiber strips into a rough yarn using a drop spindle. The drop spindle was basically the spindle and fly wheel I used in the pump drill video I made a while ago. A small stick was tied to the top of the drop spindle to act as a hook to make sure the fibers spun. I tied bark strips to the spindle and spun the spindle so it twisted the strip. When one strip ran out a new strip was added and twisted into the thread.

I then made a loom by hammering stakes into the ground and lashing cross bars to it. Stakes were hammered into the ground to hold every first string while a movable cross bar held every second string. When the bar was lifted a gap was formed where every second string was above every first string. Then when the bar was dropped a gap was formed where the opposite was true. So in this way the weaving thread could be drawn through over and under one way and then under over back the opposite way. The alternative was to weave by hand which would have taken longer.

Collecting, stripping and drying the fiber took a few days to do. Spinning and weaving took just over a day per 70 cm square. The result was a rough material about as stiff as a welcome mat. So at this stage I’m using them as mats. In future I will investigate finer fibers, such as those from banana tree stalks, as a possible material for cloth. They take more processing but produce a finer product. I may also make a permanent, portable loom that can be taken indoors when it rains.

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Bow and Arrow

I made a bow and arrows in the wild using only natural materials and primitive tools I’d made previously from scratch (as usual). The tools used were a celt stone hatchet, a stone chisel, various stone blades and fire sticks.

The stave began as a small tree (probably northern olive) about 5 cm (2 inches) in diameter which I cut to a length of 1.25 m (50 inches) using a celt hatchet. I don’t know the name of the timber but it’s very common here and is the same type I use for axe handles. I then split the stave in two using a stone chisel and mallet. Selecting one stave, I began shaping the bow. The stave twisted slightly along its length so using the chisel I split off wood at the ends of the stave but on opposite sides. This then gave a straight, flat stave. From this point I began narrowing the width and to a lesser extent the depth of the bow limbs so they tapered towards the tips of the bow limbs. This was done using the chisel, a large chopping stone and smaller scraping stones only removing wood from the belly and side of the bow. Importantly, the back of the bow was not cut at all as this would cause it to break under stress. The bark was even left on to help protect the back of the bow from accidental cuts and scrapes. At the middle of the bow I narrowed the width of the bow slightly to form a handle about 12.5 cm long. Importantly, I did not narrow the depth of the bow as this would weaken it. This narrow handle section is not essential but makes the bow easier to grip and puts the arrow closer to the center of the bow. Simple string nocks were then carved into the sides of the tips of the bow. I cut and split the wood in one afternoon, and did the rest the next day (in other words it only took about a day to make).

I made the string for the bow using the bark from a fast growing tree that grows in disturbed rain-forest clearings. The tree is a pioneer species that grows quickly with weak timber but strong bark fiber. Note in the video that the tree I took already has a new shoot and so will grow another branch from the stump. The bark was stripped and shredded. The next day I twisted the thin strips of fiber into cordage. To make cordage, two strands of fiber are individually twisted in (say) a clockwise direction but are then twisted together in an anti-clockwise direction. This way the individual strands want to unravel in one direction but can’t because they are twisted together in the opposite direction.

Next I strung up the bow. Note in the video that limb on the right side of the screen bends more than the left limb. To fix this, I left the bow strung up and scraped wood off the belly of the limb that bent the least, a process called tillering. This caused the limb to bend more so that it roughly mirrored the other limb. More tillering was done to make the limbs bend evenly along their length. If a limb bends unevenly in one spot a hinge can develop and puts uneven amounts of stress on the limb possibly causing it to break. The result of my efforts was a reasonably symmetrical bow without any obvious hinging.

For the arrows I used small saplings between 6 and 8 mm in diameter and cut to a length of 60 cm. The bark was scraped off because it would otherwise come off with use in an irregular manner causing an uneven shape effecting its flight. A notch was carved in the back of each arrow with a stone blade deep enough to accept the bow string. If the notches are not deep enough the arrow can come off the string while releasing causing a misfire. The tip of the arrow was charred in a fire and sharpened against a rock. The fire hardens the wood and makes it easier to sharpen as charred wood scrapes off with ease. The fletching was made from the feathers of a bush turkey picked up from the ground (no turkeys were harmed in the making of this video). One feather fletched one arrow each. The feather was split in half and cut into three lengths. Each fletch had the front and back reduced to its spine to be tied onto the shaft. Tree resin was used to hold the fletching one and thin pieces of bark fibre were used to lash the fletching down. Finally, the fletching was neatly trimmed using a hot coal from the fire, melting the feather to shape rather than cutting it. Each arrow took about 1 hour to make not including the time spent looking for shafts. A quiver to hold the arrows was also made from bark.

It’s noteworthy that all the shooting in this video was done less than a week after cutting the wood meaning the bow was still green. Ideally the wood should be left to season or dry out before use. I cleared a shooting range in a clearing with a bank behind it to catch stray arrows. The target was a partially rotten log so that the arrows wouldn’t get damaged too much. The shooting was done at a distance of 10 m. At this range accuracy was a bit more than 50% with reasonable force behind the shots. Accuracy would probably improve with practice and consistently made arrows. The arrows embedded themselves strongly into the wood and were difficult to remove. The string was fairly durable. I made two strings for the bow. During my practice I had the string break only 3 times while firing the arrows 200 or 300 times.

I don’t know the draw weight of this bow but it’s probably at least 15 kg (35 pounds) if not greater (I made a similar, smaller bow at home and hung a 15 kg weight that drew 33 cm). The short size of the bow (1.25m) made it easy to construct and easy to find a straight piece of wood. The string is short and also easy to make with less places to break. The 60 cm (2 foot) long arrows are short like the bow, making it easy to find straight shafts. The method of splitting the stave saved effort in removing wood as opposed to carving a bow from a log. The cross section of the bow limbs are rectangular and are less likely to break than a round cross section. The stress on the back of the bow is spread wider with a rectangular cross section than a round one. Short bows tend to shoot with high velocity too.

Hunting is heavily restricted here in Australia to conserve our native fauna. I have not hunted any animals and made the bow simply as an exercise in primitive technology. However I’ll attempt to address the question of the effectiveness as a hunting weapon. In the video I got footage of a scrub turkey standing about 5 m away. At this range most people could most certainly hit a target of that size with minimal practice. The arrow would certainly pierce it and it would provide a good meal and lots feathers for fletching new arrows, justifying the effort used to make a bow. For larger game such as pigs it could work probably at a range of 10 m provided aim was perfect and the arrows were very sharp. This weapon is definitely more accurate than a sling for a beginner and would probably be more reliable though it takes more time to make.

Making Charcoal

I made a batch of charcoal using the mound method then stored it in baskets for later use. Charcoal is a fuel that burns hotter than the wood it’s made from. This is because the initial energy consuming steps of combustion have taken place while making the charcoal, driving off the volatile components of the wood (such as water and sap). The result is a nearly pure carbon fuel that burns hotter than wood without smoke and with less flame. Charcoal was primarily a metallurgical fuel in ancient times but was sometimes used for cooking too.

To make the charcoal the wood was broken up and stacked in to a mound with the largest pieces in the center and smaller sticks and leaves on the out side. The mound was coated in mud and a hole was left in the top while 8 smaller air holes were made around the base of the mound. A fire was kindled in the top of the mound using hot coals from the fire and the burning process began.

The fire burned down the inside of the mound against the updraft. I reason that this is a better way to make charcoal as the rising flames have used up the oxygen and prevent the charcoal already made above them from burning while driving out even more volatiles .

I watched the air holes at the base of the mound and when the fire had burned right up to each opening I plugged them with mud. Once all 8 holes had be sealed, the hole in the top of the mound was sealed with mud and the mound left to cool.

The next day when the mound was cool to the touch (this can take about 2 days sometimes) I opened the mound. The resulting charcoal was good quality. Some wood near the air entries had burned to ash though these were only small twigs and leaves. This is the reason small brush is put on the out side of the mound, to be burned preferentially to the larger wood on the inside thus protecting the larger pieces of charcoal.

The charcoal that was made was hard and shiny. When broken open it had the ray structure of the wood preserved. When moving the hand through it the charcoal sounded tinny, like coral on a beach being moved by waves. These are signs of good quality. Bad charcoal is soft, breaks easily and has a muffled sound.

I intend to use the charcoal to produce hotter fires than I’m able to with wood alone. From my research, a natural draft furnace using wood (a kiln) can reach a maximum of 1400 c degrees whereas a natural draft furnace using charcoal can reach 1600 c degrees. Achieving high temperatures is necessary for changing material to obtain better technology (e.g smelting ore into metal).

Cord drill and Pump drill

A cord drill consists of a shaft, a fly wheel and a piece of cord. The fly wheel is fitted onto the shaft so it sits about a third of the way from the bottom of the stick. The middle of the cord is then fixed to the top of the shaft. To use it the two ends of the cord are wrapped around the shaft, one end of the cord is held in one hand and the other end in the other hand. The ends of the cord are then pulled outwards. As a result the shaft and fly wheel spin with the bottom of the shaft drilling into whatever needs to be drilled. As the cords are pulled out as far as they can go, the flywheel keeps the drill spinning wrapping the cord back around the shaft in the other direction. When it stops spinning, the cords are pulled outwards again sending the drill spinning in the other direction.

I used this tool to make fire in the same way I used fire sticks. I then made fly wheels from clay and fired them. Another cord drill was made with the clay fly wheel and was fitted with a stone tip. This was then used as a drill and a hole was then drilled in a piece of wood. This piece of wood was slipped over the spindle of the original cord drill upgrading it to a pump drill.

The pump drill is basically the same tool as the cord drill with a cross bar. A hole is drilled into the cross bar and the bar slid onto the shaft. The ends of the cord are then fixed to the ends of the cross bar. To use it the cord is twisted around the spindle as before and the cross bar is pumped up and down. This causes the same motion of the drill as before.

As far as fire making goes I’ll stick to fire sticks as the parts are easier to make. But for people with soft hands, this would be a good method for making fire without getting blisters. The effort during the fire making is less too. The pump drill was successful at making fire too but because their were so many moving parts I had to try many times before it worked. Cords would break, the fly wheel would loosen and the drill kept jumping out of the socket. I spent an afternoon trying to get fire with it but it eventually worked. I would be more likely to use this device as a carpentry drill. It would be useful for drilling holes in timber that was going to be assembled with pegs. One thing I need to work on is the stone drill bits. They need to be fixed firmly to the shaft so that they are in line with the spinning action. If they are off a bit the whole drill wobbles.

 

 

Baskets and stone hatchet

 

I made 2 types of basket and a celt hatchet for this video.

The first type of basket made was a coil basket. Bunches of palm leaves where wrapped in thin strips of lawyer cane to for a coil. This was then coiled into a spiral with each coil being tied to the last to keep it in place. This was done by sewing a new section of coil to the previous one. The basket was given a flat base so it could stand up but could be made any shape.

The second basket was made of lawyer cane. It started with thick strips of cane placed on the ground crossing in the centers to form an asterix shape. Importantly another half a lawyer strip was added so that the number of spokes the basket had was odd- even numbers don’t work with this type of basket. The canes were tied together in the center with a strip of bark and a piece of cane was woven in a spiral around the spokes like a spider web. When the base was wide enough the spokes were bent up to form the vertical sides of the basket. The weaving continued up the walls to the top and the ends of the spokes folded down back into the basket.

The coil method was very time consuming (about a week on and off) and made a heavy basket but used simple materials and had few gaps in it. Long grass could be used instead of palm leaves and any type of ties could be used to bind the coils. This type of basket can look very neat if done carefully (the one I made was rough). Also I would add that circular or rectangular mats might be made using this method and these materials. This might provide thick padding against the ground for sitting and sleeping and when finished could be rolled up and stored out of the way.

The woven cane baskets were much faster to make (2 or 3 hours each including harvesting materials). They used fewer materials and were lighter too. I could have easily made them bigger but wanted them to fit through the narrow door of the tiled hut.

The baskets will be used mainly for storing charcoal inside huts out of the rain but are also useful for carrying leaf mulch for the garden. They have flat bases meaning they can stand upright and even be stacked on top of each other.

I also made a small celt hatchet for lighter work. The big celt I made is useful for chopping bigger trees but is overkill for saplings and smaller trees. The method used was basically the same for the big celt though this time I used no fire hardening. The handle came from a branch cleared from the the sweet potato patch and had sat for a few months seasoning on the ground. It was much harder to shape than green wood but was hard enough to not need fire hardening. So far I’ve used it without the handle splitting though the basalt head chipped when trying to chop dry eucalyptus branches (an especially hard wood)- I re sharpened it and it works on other woods OK.

Sling

Sling

A sling is a weapon for throwing stones with greater force and range than by hand alone. It consists of a pouch and two lengths of cord. A rock is placed in the pouch and the two ends of the cords are held in the hand. The sling is then swung over the head to gain momentum. The sling is then swung forward in a throwing action and one end of the cord is released causing the pouch to open releasing the stone to fly at the target.

I made this sling from bark fibre. A branch was taken from a fast growing tree and the bark peeled from it. The inner bark was then separated from the outer bark by hand and pulled apart to form thin strips. These were left overnight to dry slightly. The strips were twisted into cordage (thin ropes) with two strands.

Cordage can be made from many natural fibres. Two or more strands are both twisted individually in one direction (clockwise in this case) and are then twisted together in the opposite direction (anti-clockwise). The two strands want to unravel in the clockwise direction but are unable to due to being twisted together in the opposite direction.

The cord was then tied in such a way that a section of three cords was formed in the middle of the length. A single strip of bark was woven between the three pieces of cord to form a pouch to hold stones. A loop was tied at one end of the sling to slip over the finger and a knot tied in the other end to be held onto and released while firing. The length of the sling was a little more than my outstretched arms pan. Latter I shortened it by tying knots in the cord.

To use the sling the loop is slipped over the finger and the knot in the other end is held between the thumb and forefinger. A stone is placed in the pouch and the sling is swung around above the head one or more times. At the appropriate part of the swing the sling is swung forward with a throwing action and the knot is released. The pouch then opens up releasing the stone which if aimed correctly flies toward its target with great velocity and momentum, much more so than if thrown by hand.

The training was difficult. The last time I used a sling was about eight years ago. Having said that, I manage to hit the targets a few times. In the video, the first target I set up and filmed was a pot sherd on a stick at about 10m away. I hit it first go though it was most likely a fluke. I then set up a post at 20 m and was not so accurate. I set up more pots and tiles on sticks in a clearing at 10 m, then in a creek at 15m and finally tiles in the clearing again at 10 m. With practice I noticed I got better.

The advice I’d give would be to set up targets 10- 20m away and practice with the sling. Aiming the sling is roughly this: Swing the sling in the same plane the target is on (determines y- axis), then time the release of the sling when it will let the stone go towards the target (determines x- axis). Use larger stones as they swing slower and are easier to time the release. Larger stone also carry more momentum. The stones should also be smooth so they fly straight and don’t grip onto the pouch when released but fly out smoothly on target instead.

I built the sling with a solid pouch like those I used as a kid, but my research showed that some have a split pouch. This might be a better design but I didn’t test it during this project. The bark fibre worked well. It was durable, inflexible and made a good material for the sling.

The benefit of the sling as a weapon is that it is easy to make, is very portable, and has few components to break and the ammunition (stone) is everywhere. The disadvantages are that it is difficult to learn to use and cannot be fired in thick forest for lack of room to swing it.

sling

Chimney and pots.

I built a fireplace and chimney onto the tiled roof hut for light and cooking purposes. An external fireplace was built in the back wall of the hut. This fireplace was not for heating. That was taken care of by the pre-existing underfloor heating system. I camped in the hut one night and the fireplace gave good light to see by while the underfloor heating made it comfortably warm to sleep in.

I also needed more and larger pots for carrying water and boiling it. Clay from the creek bank was dug and used to make the pots. Stones were removed from the clay and broken tiles left over from the construction of the hut were crushed and added as grog. This prevents pots from cracking during drying and firing. The clay was then mixed by hand to form a homogenous mixture.

A cooking pot and 4 large pots (just under 25cm tall and 25cm wide) were made using the coiling method. Some layers of the pot had lines scraped on top of them to help the next layers stick to them better, but this was probably unnecessary. The pots were rubbed with a snail shell and a smooth seed pod in a process called burnishing. This adds strength to the pots and makes them more waterproof. I only burnished them lightly. If done well they can get a very shiny finish.

The kiln, originally used for firing roof tiles for the hut, was used to fire the larger pottery. Originally I fired previous pots in small pit fires. But the kiln allowed me to fire larger pots with a lower breakage rate than pit fire. The quality of kiln fired pots is also higher than pit fired pots as the kiln reaches a higher and less variable temperature. One of the four large pots cracked during firing. In total the project yielded 3 large water pots and one small cooking pot.

I used the large pots to carry water from the creek to irrigate a sweet potato patch behind the wattle and daub hut (across the creek from the tile hut).  The smaller pot was used to boil the creek water. First I put the pot full of water back in the kiln and fired it which brought the water to a simmering boil. Another day I decided to try boiling the water with rocks. Wooden tongs were made using a split sapling and the fireplace was lit. Quartz stones were placed in the fireplace and more wood piled on top. The stones took about 15 or 20 minutes till they glowed red hot. They were then taken from the fire using the tongs and placed in the pot of water. The small pot only took about 4 rocks to boil violently. Any pathogens that were in the water would have surely died from the 20 minutes or so of rolling boil (although I’ve never become sick drinking this water straight anyway). I drank the water and it was like warm tea.