Oil Lamps

Part of Lighting

Building and operating oil lamps from animal fat and plant oils before electrical lighting is available.

Why This Matters

Oil lamps are the most reliable pre-electric light source available and require nothing but a container, a wick, and liquid fuel. They have illuminated human settlements for at least 100,000 years. Before you have a functional electrical system, oil lamps bridge the critical gap between sunset and sleep — extending productive hours and providing light for safety, medicine, and community life.

Even with electrical lighting operational, oil lamps remain valuable as backup. A lamp that needs no battery, no wiring, and no electrical knowledge is irreplaceable when the generator fails or the battery bank runs dry. Every household should maintain at least two functional oil lamps with a reserve fuel supply.

Understanding oil lamps also introduces concepts — fuel types, combustion management, wick design — that apply to other fuel-burning technologies including heaters, cookstoves, and eventually gas lighting.

Fuel Types and Characteristics

The quality of an oil lamp depends primarily on fuel quality. Any flammable liquid can be burned, but the differences in smoke, smell, brightness, and health effects are large.

Fuel	Light Quality	Smoke	Smell	Source
Rendered beef tallow	Moderate	Heavy	Strong	Cattle, sheep fat
Rendered pork lard	Moderate	Moderate	Moderate	Pig fat
Fish oil	Moderate	Heavy	Very strong	Oily fish, fish livers
Olive oil	Good	Very low	Pleasant	Olive trees
Linseed/flax oil	Good	Low	Mild	Flax seeds
Sunflower oil	Good	Low	Mild	Sunflower seeds
Castor oil	Excellent	Very low	Mild	Castor plant
Beeswax (melted)	Good	Very low	Pleasant	Bees
Pine resin/turpentine	Bright	Heavy	Strong	Coniferous trees
Kerosene	Very good	Low	Moderate	Petroleum reserves
Vegetable glycerin	Poor	Very low	None	Soap-making byproduct

Rendering animal fat: Raw fat contains water and protein that cause spattering and smoke when burned. Render it first:

1. Cut fat into small pieces, removing all meat and skin
2. Heat slowly in a pot with a small amount of water
3. Fat melts; impurities sink or rise as foam
4. Strain through cloth while still liquid
5. Cool — purified rendered fat solidifies white and clean
6. Multiple renderings improve quality

Infusing fuels: Fragrant herbs (lavender, rosemary) added to olive oil during gentle heating transfer some scent to the oil. This reduces the smell of the lamp during burning. A small addition of beeswax to tallow increases burning temperature slightly and reduces dripping.

Lamp Designs

The Dish Lamp

The oldest and simplest design. A shallow dish holds oil; a wick lies across the edge with one end submerged and one end lit.

Construction:

1. Any shallow fireproof container — pottery shard, clamshell, carved stone, tin lid
2. Fill with fuel to within 1 cm of the rim
3. Twist a wick from cotton cloth, plant fiber (flax, hemp), or twisted dried grass
4. Lay wick from inside the oil, up over the edge, with 5–10mm extending beyond the rim
5. Light the exposed wick tip

This is functional but messy — oil spills easily, the flame is uncontrolled, and there is no way to adjust brightness.

The Closed Lamp with Wick Tube

More controlled than a dish lamp. The fuel reservoir is mostly sealed, with only a small tube or channel guiding the wick.

Traditional clay lamp:

1. Form a small closed vessel from clay (egg-sized to fist-sized is practical)
2. Leave a fill hole on top (thumb-sized)
3. Form a pinched spout or attach a small tube at the front — this holds the wick
4. Fire the lamp in a kiln or long in coals until hardened
5. Fill with oil through the top hole, thread wick through the spout, light

This design is stable, has low spill risk, and the wick tube controls flame height.

The Float Lamp

Produces the most stable flame. The wick floats on the oil surface, maintaining a constant relationship between wick tip and fuel level as oil is consumed.

Construction:

1. Use a wide, stable container (wide-mouthed ceramic jar, can, deep plate)
2. Fill with oil to within 3 cm of rim
3. Cut a small disc from a cork, piece of wood, or folded tin — about 3 cm diameter
4. Punch a hole through the center, slightly smaller than the wick diameter
5. Thread the wick through the hole so it extends 5–10mm above the float and submerges below
6. Float the assembly on the oil
7. Light the protruding wick end

The float descends as oil is consumed, keeping the wick/oil interface constant. Flame height remains consistent throughout burning. This design was used in the classical world and medieval Europe.

The Kerosene-Style Wick Lamp

With salvaged kerosene, alcohol, or other petroleum distillates, the kerosene lamp design is far superior to open-dish designs. The wick advances via a threaded mechanism, allowing precise brightness control.

Reconstructing from parts:

1. A sealed metal tank with a wick tube soldered to the top
2. A flat cotton wick (5–10mm wide) fed through the tube
3. A knurled wheel that grips the wick and advances or retreats it
4. A glass chimney above the flame to create upward draft and protect the flame from drafts

The chimney dramatically improves combustion — it draws fresh air under the flame and carries hot combustion gases up and away. A kerosene lamp with a chimney burns several times brighter than a wick lamp without one and produces far less soot.

Making a chimney: Any glass cylinder that fits over the burner assembly. Cut the bottom off a glass bottle with a hot wire or scoring method. Improvise from sheet glass bent into a cylinder with lead solder at the seam.

Wick Construction and Maintenance

The wick is critical. It must draw fuel by capillary action, burn evenly without excessive consumption, and be trimmed regularly.

Best wick materials:

• Tightly woven cotton cloth, cut into strips 5–15mm wide
• Cotton rope (multi-strand rope, not twisted synthetic)
• Braided flax fiber
• Multiple twists of fine plant fiber (cattail fluff, milkweed fluff work reasonably)

Wick preparation: Soak the wick in salt water for 30 minutes, then dry completely before use. Salt impregnation reduces the rate at which the wick itself burns, extending its life and reducing mushrooming (the charred, widened tip that forms during burning).

Trimming: Every few hours of burning, the wick tip chars and mushrooms. This charred cap reduces capillary action, increases smoke, and dims the flame. Snuff the lamp, wait for it to cool slightly, and pinch off the charred tip — about 1–2mm. Then relight. A trimmed wick burns brighter, cleaner, and longer.

Wick width and brightness: Wider wicks produce more light but consume more fuel and require wider wick channels. A 10mm flat wick produces roughly 30–40 lumens. A 5mm round wick produces 10–20 lumens. Compare to a candle at 10–12 lumens — even a simple oil lamp with a moderate wick outperforms candles.

Operating Safely

Oil lamps are reliable but not without hazard. The majority of pre-electric building fires came from open-flame lighting.

Stability first: Place lamps on flat, stable surfaces. Never place on the edge of a surface where they can be knocked off. Heavy ceramic or metal lamps are more stable than lightweight tin.

Clearance: Keep at least 30cm of clear space above a lamp flame. Flammable material (thatch, wood beams, fabric) above a lamp is the main fire risk.

Lamp holders: A simple lamp holder — a bracket bolted to a wall, or a box with low sides that catches any spill — dramatically reduces fire risk. The holder keeps the lamp in a fixed position and contains any oil that spills during refueling.

Refueling: Extinguish the lamp and let it cool before adding fuel. Adding fuel to a hot lamp risks igniting the fuel stream. Give the lamp 5 minutes to cool after extinguishing before opening the fill hole.

Storage: Store bulk oil fuel in sealed, non-combustible containers (ceramic jars, metal cans) away from any open flame. A coolstorage area reduces evaporation losses.

Carbon monoxide: Oil lamps burning in poorly ventilated spaces produce some carbon monoxide. Always ensure at least a small crack of ventilation when using oil lamps indoors overnight. Never use large lamps in small, sealed spaces.

Fuel Production

Pressing Plant Oils

If no scavenged petroleum or animal fat is available, cold-press plant oils from available seeds:

1. Collect seeds: Sunflower, flaxseed, rapeseed, hemp seed, sesame. All produce burnable oil.
2. Remove hulls if possible: Improves oil yield.
3. Crush seeds: Use a mortar and pestle, or pass between two flat stones.
4. Press out oil: Wrap crushed seeds in cloth, place in a container, put a board on top, load with heavy rocks. Oil drains out over several hours.
5. Settle and strain: Allow 24 hours for sediment to settle. Pour off clear oil. Strain through fine cloth.

Yield from cold pressing is 20–35% of seed weight as oil, depending on seed type and pressure applied. A screw press (see Machine Tools) dramatically improves yield.

Rendering Tallow at Scale

With a community livestock operation, rendered tallow becomes available in quantity. Key considerations:

• Cattle and sheep produce higher-quality (harder, less smoky) tallow than pigs
• Render fat promptly after slaughter — raw fat spoils quickly
• Multiple renderings produce progressively cleaner oil
• Store rendered tallow in sealed ceramic or metal containers — it keeps for months in cool conditions