Pipe Making

Part of Water Systems

Pipes are the arteries of civilization — they carry water under pressure through terrain that open channels cannot cross, distribute water within buildings and to individual homes, and handle sewage disposal. Every pipe material has its own construction method, pressure rating, and lifespan.

Choosing the Right Pipe Material

The best pipe material depends on what you have available, the pressure required, and the intended service life.

Material	Pressure Rating	Lifespan	Difficulty to Make	Best For
Bored log (wooden)	Low (5-15 psi)	10-30 years	Easy	Low-pressure supply, short runs
Clay (fired ceramic)	Low (gravity only)	50-100+ years	Moderate	Drainage, sewage, gravity supply
Lead	High (50+ psi)	100+ years	Moderate	Short connections (NOT for drinking water)
Copper	High (100+ psi)	50-100 years	Difficult	Drinking water, high-pressure lines
Cast iron	Very high (200+ psi)	100+ years	Difficult	Main supply lines, high pressure
Bamboo	Low (5-10 psi)	3-5 years	Easy	Tropical regions, temporary systems

Never Use Lead for Drinking Water

Lead dissolves slowly into water, especially soft or acidic water. Lead poisoning causes brain damage, organ failure, and death — particularly in children. Lead pipes are acceptable only for non-potable uses (irrigation, industrial water, drainage). Ancient Rome’s lead water pipes likely contributed to widespread chronic lead poisoning.

Wooden Pipes (Bored Log)

The easiest pipe to make with basic tools. Used extensively in Europe and colonial America through the 1800s.

Construction

1. Select logs — choose straight-grained hardwood: elm is traditional (rot-resistant when waterlogged), oak and larch also work. Avoid softwoods — they rot faster.
2. Diameter: 15-30 cm for main supply, 8-15 cm for distribution.
3. Boring:
   • Secure the log horizontally on supports.
   • Use a long auger (a T-handled drill with a spoon or shell bit) to bore through the center.
   • For logs longer than 2 meters, bore from both ends and meet in the middle.
   • Bore diameter: 5-10 cm for a supply main.
4. Joining:
   • Taper one end of each log to a point.
   • Ream the opposite end to accept the taper.
   • Drive the tapered end into the reamed end with a mallet.
   • Wrap the joint with tarred rope or seal with pitch for water-tightness.

Parameter	Value
Typical log length	2-4 meters
Bore diameter	5-10 cm
Operating pressure	Up to 15 psi (1 atmosphere)
Service life (buried)	15-30 years (elm), 10-20 years (oak)

Preserving Wooden Pipes

Wooden pipes last longest when buried below the frost line and permanently saturated with water. A wooden pipe that dries out and then re-wets develops cracks and leaks. If the system must be drained for maintenance, refill as quickly as possible.

Fittings

• Tees and elbows: Carve from solid wood blocks. Bore holes at the correct angles and connect log pipe ends.
• Valves: Insert a wooden plug (tapered) into an oversized bore hole at control points. Remove or insert the plug to control flow.

Clay Pipes (Fired Ceramic)

Excellent for drainage and gravity-flow water supply. Extremely durable and corrosion-proof.

Construction

1. Prepare clay — use potter’s clay, well-wedged (kneaded to remove air bubbles) and at a firm but workable consistency.
2. Form the pipe:
   • Hand-building method: Roll a thick slab of clay around a wooden dowel or pole of the desired inner diameter. Smooth the seam by wetting and pressing.
   • Extrusion method: Force clay through a die with a central core, producing a continuous hollow tube. Requires a pug mill and die — more efficient for large quantities.
3. Size: Typical diameters 10-30 cm, wall thickness 1-2 cm, length 30-60 cm per section.
4. Dry slowly — too-fast drying cracks the pipe. Allow 1-2 weeks in shade.
5. Fire in a kiln at 900-1100 degrees C. Higher temperatures produce harder, more waterproof pipes.
6. Glaze the interior (optional but recommended) — salt glazing (throwing salt into the kiln at peak temperature) or slip glazing produces a glassy interior surface that resists water absorption and root intrusion.

Joining

1. Bell and spigot — one end of each pipe is flared out (the bell), the other left straight (the spigot). The spigot fits inside the bell of the next pipe.
2. Seal the joint with:
   • Oakum (tarred hemp rope) packed into the gap first
   • Then molten lead, lime mortar, or clay slip to complete the seal
3. Align carefully — maintain consistent downhill gradient for drainage pipes.

Pressure Limitations

Clay pipes are excellent for gravity-flow systems but cannot handle significant internal pressure. Maximum safe pressure for unglazed pipe is essentially zero — gravity flow only. Salt-glazed pipes can handle modest pressure (5-10 psi) with well-sealed joints.

Metal Pipes

Cast Iron Pipes

The strongest and most durable pipe available in a rebuilding scenario.

Casting process:

1. Make a mold — traditionally, an outer sand mold with a cylindrical core (sand around a metal core bar) to form the hollow center.
2. Pour molten iron at 1,200-1,400 degrees C into the mold.
3. Centrifugal casting (superior method): rotate the mold rapidly while pouring iron. Centrifugal force distributes the iron evenly and produces denser, stronger pipe.
4. Cool slowly and remove from mold.
5. Machine the ends — one end flared for bell, one left straight for spigot.

Parameter	Typical Value
Diameter	50-300 mm
Wall thickness	6-12 mm
Length per section	1-3 meters
Pressure rating	100-250 psi
Service life	100+ years

Joining: Bell and spigot with oakum packing and molten lead seal, or flanged joints with bolts and gaskets.

Copper Pipes

Safe for drinking water, naturally antimicrobial, and capable of handling high pressure.

Construction:

1. Start with copper sheet — hammered or rolled to uniform thickness (1-2 mm).
2. Form into tube — wrap the sheet around a mandrel of the desired diameter.
3. Join the seam — solder with silver solder or braze the longitudinal seam.
4. Draw to final size (if capability exists) — pull through progressively smaller dies to reduce diameter and increase wall density.

Joining copper pipes:

1. Soldered joints — clean the pipe end and fitting interior with abrasive. Apply flux (rosin or zinc chloride). Heat the joint and flow solder into the gap by capillary action.
2. Compression fittings — if you can machine threaded brass fittings, a nut compresses a soft ring (olive) around the pipe.

Sheet Metal Pipes (Wrought Iron or Steel)

For situations where casting is not possible:

1. Cut a strip of sheet metal to the correct width (circumference of desired pipe).
2. Roll into a tube using a mandrel.
3. Rivet or forge-weld the seam.
4. Seal with solder or by caulking the rivet line.

Bamboo Pipes

In tropical regions, bamboo provides an immediately available pipe material.

Construction

1. Select large-diameter bamboo — 5-10 cm internal diameter.
2. Remove internal nodes — drive a long rod through the bamboo to punch out the internal diaphragms at each node.
3. Join sections — insert the smaller end of one section into the larger end of the next. Seal with tar, wax, or wrapped cord.
4. Support at intervals — bamboo weakens when unsupported over long spans. Place supports every 1-2 meters.

Extending Bamboo Pipe Life

Soak cut bamboo in running water for 2-4 weeks before use — this leaches out starches that attract insects and fungus. Alternatively, heat-treat by passing bamboo over a fire until the surface oils emerge and glaze. Treated bamboo pipes last 3-5 years instead of 1-2 years.

Pipe Sizing

Flow Calculations

Pipe diameter directly affects flow capacity. A pipe twice the diameter carries approximately four times the water at the same pressure.

Pipe Diameter (cm)	Approximate Flow (liters/minute) at 1 m/s
5	12
10	47
15	106
20	188
30	424

Rule of thumb for community water supply: Allow 50-100 liters per person per day. For a community of 200 people needing 15,000 liters/day, a 10 cm pipe flowing at 1 m/s delivers enough in about 5 hours.

Common Mistakes

1. Using lead for drinking water — lead poisoning is cumulative and devastating. Reserve lead pipes for non-potable uses only.
2. Insufficient burial depth — pipes above the frost line freeze and burst in winter. Bury at least 30 cm below the local frost depth.
3. Ignoring thermal expansion — metal and clay pipes expand when carrying hot water. Allow for movement at joints or they crack.
4. Poorly sealed joints — most water loss in pipe systems occurs at joints, not through pipe walls. Take time to properly pack and seal every connection.
5. Undersizing pipes — too-small pipes create friction losses that reduce flow dramatically. When in doubt, use the next larger diameter.

Summary

Pipe Making — At a Glance

• Bored wooden logs (elm preferred) are the easiest pipes to make — suitable for low-pressure supply up to 15 psi
• Fired clay pipes are extremely durable and ideal for gravity-flow drainage and sewage
• Cast iron provides the highest pressure rating (200+ psi) and longest service life (100+ years)
• Copper pipes are safe for drinking water and can be made from sheet metal soldered along the seam
• Never use lead pipes for drinking water — lead poisoning is cumulative and deadly
• Bamboo is immediately available in tropical regions but requires treatment to last more than 1-2 years
• Bell-and-spigot joints sealed with oakum and lead (or mortar) are the standard joining method
• Size pipes generously — undersized pipes lose capacity rapidly to friction