Practical Projects — Build, Cool, Pump, Power, Store

1. Evaporative Cooling & DIY Air Conditioning

Evaporating water absorbs a lot of heat — that's the physics behind every cheap cooler. It works brilliantly in dry heat and poorly in humid heat (the air is already saturated).

Evaporative (swamp) cooler

• Wet-sheet / hung cloth: hang a wet sheet in a breezy window or doorway; air passing through it cools as the water evaporates. Re-wet as it dries.
• Fan + wet pad: blow a fan through a wet pad, screen, or hung straw. A bucket dripping onto the pad keeps it wet. The classic “swamp cooler.”
• Zeer pot (pot-in-pot fridge): a smaller clay pot inside a larger one, the gap packed with wet sand, a damp cloth on top. As water evaporates from the sand it chills the inner pot — keeps vegetables days longer with no power. Keep it in shade with airflow.

Without evaporation (works in humidity)

• Ice/cold-water fan: a fan blowing over a tray of ice or a coil of tubing carrying cold (e.g. well or stream) water gives real cooling without adding humidity.
• Passive design beats machines: shade the building (especially windows), use thermal mass (stone/earth walls stay cool), ventilate hard at night and seal up during the day, and run a cool earth-tube (air drawn through a buried pipe) into the room.

See Shelter & Construction for passive-cooling building design.

2. Air Filtration & Clean Air

Wildfire smoke, dust storms, mould, and fallout particles are all airborne particulates you can filter cheaply.

• Personal: a well-fitted N95/FFP2 mask, or a damp cloth folded several times, knocks down dust and smoke for short exposure. Damp cloth is a last resort, not protection against gases.
• Activated charcoal (made by heating wood without air — see Chemistry) adsorbs odours and many gases; layer it after a particulate pre-filter for a fuller filter.
• Shelter air: seal a single room, filter incoming air, and keep it slightly positively pressured so unfiltered air leaks out, not in. For chemical/biological/radiological threats see NBC / EMP.

3. Dams & Hydro Power

A small dam stores water, raises its level for irrigation, and creates the “head” (drop) that powers a water wheel or turbine. Power available ≈ head × flow — both a tall drop and a strong flow give more energy.

Small check dams & weirs

• Build across a stream with earth, rock, or wire-cage gabions filled with stone. Key the dam firmly into both banks and the streambed so water can't cut around or under it.
• Always build a spillway — a lower overflow channel, lined with rock, that safely carries flood water around the dam. This is not optional.

Turning head into power

• High drop, low flow (a hillside stream): a Pelton wheel — jets of water hit cupped buckets on a wheel. Very efficient for tens of metres of head.
• Low drop, big flow (a river/mill race): an overshot or undershot water wheel, or a propeller turbine.
• Pipe the water down a penstock to the wheel/turbine, spin a generator (or grind a mill directly). Full builds are in Power Generation.

4. Pumping Water Without Mains Power

Match the method to your situation: lifting from a well, moving water uphill, or irrigating a field.

• Hydraulic ram pump: the standout — it uses the energy of flowing water to pump a fraction of it uphill, continuously, with no external power and only two moving valves. Needs a stream with a little fall above the pump. Can lift water tens of metres day and night, unattended.
• Rope-and-washer pump: a loop of rope with rubber washers runs up a pipe through a well; rubber washers drag water up as you turn the wheel. Cheap, DIY, and lifts from deep wells.
• Hand / lift pump: a piston in a cylinder with two valves — the classic village pump. Reliable and repairable.
• Treadle pump: foot-powered, moves lots of water for irrigation from a shallow source.
• Archimedes screw & chain pump: lift large volumes a short height for fields and drainage.
• Shadoof: a counterweighted lever that swings a bucket up from a stream — ancient, simple, effective.
• No pump at all: a siphon moves water over a lip and downhill using gravity alone — start it once and it runs itself as long as the outlet is lower than the source.

Also see Water Systems for wells and gravity distribution.

5. Toilets & Sanitation Systems

Choose by water and time

• Sawdust / composting bucket (humanure): a bucket with a seat; cover each use with sawdust, leaves, or soil to kill smell and flies; empty into a dedicated, contained compost pile that heats up and is left a full year+ before use on non-food plants. No water needed. See the bundled Humanure Handbook.
• Pit latrine: a deep hole with a slab and a tight-fitting cover. A vent pipe painted black (a “VIP” latrine) draws flies up and out. When two-thirds full, cap it and dig a new one. Twin-pit and “arborloo” (plant a tree on the filled pit) systems rotate.
• Bucket toilet with cover material for short-term or indoor use, emptied to a latrine or compost.

Siting rules (non-negotiable)

• At least 30 m (100 ft) from any water source, and downhill of wells and springs.
• Pit bottom well above the water table.
• Downwind and away from the kitchen and eating areas.

Handwashing is half the benefit: rig a “tippy-tap” (a tip-to-pour water container worked by a foot lever) with soap or ash right beside every toilet. More in Food & Water → Sanitation.

6. Checking for Radiation

You cannot see, smell, feel, or taste radiation — which is exactly why measuring it (or following the rules when you can't) matters.

If you have instruments

• A Geiger counter or dosimeter reads dose rate / accumulated dose directly. Survey food, water, surfaces, and yourself; track your accumulated dose over time.

If you don't — the improvised KFM

The Kearny Fallout Meter is a build-it-yourself electroscope (two charged foil leaves that fall together as radiation discharges them) accurate enough to make life-or-death shelter decisions. Full plans are in the bundled Nuclear War Survival Skills and the NBC / EMP section.

Decontamination: fallout is dust — removing your outer clothing and shoes removes most contamination; washing skin and hair removes more. Filter and let water settle; food in sealed containers is safe (wipe the outside).

7. Building a Grain Mill

Whole grain stores for years but you can't eat it until it's ground. A mill turns stored wheat, maize, or beans into flour and meal — a daily necessity once it's your staple.

By hand

• Quern (saddle or rotary): two stones — grain is crushed between a fixed lower stone and a turned/rubbed upper stone. The rotary quern (one stone spinning on another, grain fed through a central hole) is the classic hand mill and is buildable from hard, dense stone.
• Metal burr / plate mill: a hand-cranked mill with two grooved discs — the best option if you can salvage or stockpile one. Mortar and pestle works for small amounts.

Powered

• Couple a burr or stone mill to any rotary power: a water wheel (the historic watermill), a windmill, a pedal drive, or an animal walking a circle (a horse mill). Milling is steady, low-speed work — ideal for water or animal power.

Tip: grind little and often — wholemeal flour with its oils goes rancid in weeks, but the whole grain keeps for years. Store grain, not flour. See Power Generation to drive the mill.

8. Breeding Herd Animals & Chickens

The goal is a flock or herd that renews itself indefinitely. That needs fertility management, sensible selection, and enough genetic diversity to avoid inbreeding decline.

Chickens

• You need a rooster for fertile eggs (~1 per 8–12 hens). Hatch with a broody hen (the natural way) or an incubator — about 21 days at ~37.5 °C and controlled humidity. Candle eggs at ~day 7–10 to remove infertile ones.
• Brood chicks warm (start ~35 °C, dropping ~3 °C/week), dry, with chick crumb and clean water. Keep the best pullets for laying; grow out or eat surplus cockerels.
• Rotate or swap in an unrelated rooster every year or two to keep the line vigorous.

Goats, sheep, cattle, pigs

• One male serves many females — so the scarce, valuable genetics are the males. Keep or trade for an unrelated buck/ram/bull and rotate him before he breeds his own daughters.
• Gestation: goats & sheep ~150 days, pigs ~115 days, cattle ~283 days. Time matings so births land in good weather with feed available.
• Select your keepers for hardiness, mothering, and productivity; eat or trade the rest. Keep simple records of who's related to whom.

9. Long-Term Food Storage

Spoilage is microbes plus oxygen plus warmth plus pests. Remove any of those and food keeps; remove several and it keeps for years. (The chemistry behind this is in First Principles.)

Dry staples — years to decades

• Store grains, beans, rice, pasta, sugar, and salt dry, cool, dark, and airtight. Food-grade buckets or Mylar bags with oxygen absorbers (or flushed with CO₂ from a little dry ice) keep oxygen and moisture out — white rice and wheat then last decades.
• Longest keepers: white rice, wheat, dried maize, salt, sugar, and honey (effectively indefinite). Short keepers: brown rice, nuts, wholemeal flour, and anything oily — the fats go rancid in months. Store the whole grain, not the flour.

Other methods

• Root cellar: a cool, humid, dark space (a dug-in cellar, buried barrel, or north-side store) keeps potatoes, carrots, beets, cabbages, and apples for months.
• Preserve the rest: canning (the bundled USDA Complete Guide to Home Canning has tested times — botulism is the real risk, so follow it exactly), drying, salting, smoking, fermenting (sauerkraut, kimchi), and storing in fat (confit, pemmican).

Pests & rotation

• Beat weevils and moths with airtight containers, bay leaves, food-grade diatomaceous earth, or by freezing grain for a few days to kill eggs before sealing.
• Label everything with the date and rotate first-in, first-out. Store more of the staples you actually eat. Full methods are in Food & Water → Preservation.

10. DIY Gravity Bio-Water Filter

Purifying (boiling, bleach, SODIS) kills germs but doesn't remove mud, sediment, or much of the taste — and it costs fuel every time. A gravity filter cleans murky water continuously, all day, with no power and no fuel. Build one and feed it through the day.

The two-bucket bio-sand / charcoal filter

Stack the media in a container (two food-grade buckets, one draining into the other through a tap, or a single tall barrel with an outlet near the base):

1. Top — coarse gravel (a few cm): catches leaves and grit.
2. Then clean sand (the main filter, 30–50 cm deep): traps fine particles. Over days a living “biolayer” forms on top that eats pathogens — this is what makes it a bio-sand filter, so don't disturb the top and keep water standing above it.
3. Then crushed charcoal (10–15 cm — make it by burning hardwood without air, see Chemistry): adsorbs odours, colour, and many chemicals.
4. Bottom — fine gravel over the outlet, with a cloth at the tap to stop media washing out.

Pour dirty water in the top; clear water runs from the tap. A bucket of cloudy water comes out clear.

A ceramic pot filter (fired porous clay, ideally with colloidal silver) is the other classic — it filters fine enough to remove most bacteria on its own. Improvise a quick field version with sand/charcoal/gravel layered in a cloth, sock, or bottle. More water methods in Water Systems and Food & Water.

11. Making Salt

Salt is not optional. Your body needs it to live (lose too much through sweat and you cramp, weaken, and die), and it's the backbone of preserving meat, fish, hides, and vegetables. Almost nobody stockpiles enough — so knowing how to make it is a quiet superpower.

From seawater or salt springs

• Evaporation (sun): run shallow ponds or trays of seawater and let the sun and wind evaporate it. As it concentrates, salt crystallises out — rake and collect it. Salt-pan terraces have fed civilisations this way for millennia. Best in hot, dry, windy weather.
• Evaporation (fire): boil seawater (or brine from a salt spring) down in a wide pan. Skim off scum; as the water nears gone, salt crystals form — scoop them out. Fuel-hungry, so finish sun-concentrated brine over fire rather than boiling from full strength.
• Concentrate first: a litre of seawater holds only ~35 g of salt, so pre-concentrate by sun/freezing before you spend fuel boiling.

From the land (inland)

• Salt springs and salt licks: brine seeps and natural licks (animals show you where) are boiled down like seawater.
• Salty plants & ash: some coastal/marsh plants (glasswort, certain grasses) are burned and the ash leached — yields a salty, mineral-rich seasoning (more potassium than sodium, but useful).
• Rock salt / halite where it occurs — dissolve, filter out grit, and re-evaporate for clean salt.

Store salt bone-dry and airtight (it pulls water from the air and cakes). Clean salt also gives you brine for food storage, hides for leather, and electrolyte solution for the sick (see ORS).

12. Firefighting Without a Brigade

Prevent it

• Keep flames away from anything that burns; clear a non-flammable zone around stoves and fires.
• Sweep chimneys and stovepipes regularly — creosote buildup causes chimney fires that spread to the roof.
• Store fuel (petrol, alcohol, lamp oil) outside living space, sealed, away from flame and sun.
• Never leave a flame, stove, or candle unattended; douse fully before sleep.
• Cut firebreaks around your site against wildfire; keep the roof clear of leaves.

Fight it (small fire, first seconds)

1. Get people out first. No possession is worth a life. Have an escape plan and a meeting point.
2. Smother or cool it while it's small: a bucket of water, a damp blanket, sand, or earth thrown over it. Keep buckets of water and sand near every fire and stove.
3. A wet blanket or beating with a wet sack knocks down grass and small fires.
4. Remove the fuel: drag burning material away from what hasn't caught; break the path the fire would spread along.

If it's beyond a bucket, fall back, save people, and create distance/firebreaks to stop it spreading. Treat burns per Medical → Burns; smoke inhalation is a medical emergency.