Forge Setup

Part of Metalworking

Building a complete blacksmith’s forge from scratch — the workshop that makes all other metalwork possible.

Why This Matters

The forge is the heart of metalworking. Without a properly built and equipped forge, you cannot heat iron to forging temperature, cannot weld, cannot harden steel, and cannot produce the tools your community needs. A well-designed forge is not just a fire — it is an engineered system that concentrates heat exactly where needed, controls airflow precisely, manages fuel efficiently, and provides a safe, productive workspace for hours of continuous operation.

Many rebuilding communities will attempt metalwork with an improvised campfire and a rock for an anvil. This works for the simplest tasks — bending heated rebar, straightening nails — but it cannot sustain the temperatures, control, or duration needed for real smithing. A proper forge, built with thought and local materials, transforms metalworking from a desperate improvisation into a reliable production capability.

Building the forge is also a community investment. A single forge, operated by even one trained smith, can supply an entire settlement with tools, hardware, cookware, weapons, and repair services. The few days spent building it correctly pay dividends for years.

Choosing the Forge Type

Side-Blast Forge (Recommended)

The most versatile and historically common design. Air enters from the side through a tuyere into a firepot (a depression where the fire burns). The fire is open on top, giving full access to the work.

Advantages: simple to build, easy to adjust fire size, accommodates any size workpiece, good visibility of the work in the fire.

Disadvantages: uses more fuel than a bottom-blast, fire tends to spread if not managed.

Bottom-Blast Forge

Air enters from below through a grate in the bottom of the firepot. Common in later European and American smithies.

Advantages: more concentrated heat, uses less fuel, clinker falls away from the fire.

Disadvantages: harder to build (needs a grate and ash dump), grate must be replaced periodically, very small firepot limits workpiece size.

For a first forge with available materials, the side-blast is recommended. It requires only a tuyere pipe and can be built from earth, stone, or brick with no metal components except the tuyere itself.

Building the Forge Structure

Materials Needed

• Structure: stone, brick, rammed earth, or adobe. The forge table is essentially a waist-high platform with a fire on top. It does not need to be refractory clay — only the firepot lining needs heat resistance.
• Firepot lining: refractory clay (50% clay, 25% sand, 25% grog/straw). This lines the area immediately around the fire.
• Tuyere: iron pipe (3–4 cm diameter) or a clay pipe for the air inlet. Iron is preferred — clay tuyeres crack with thermal cycling.
• Bellows or blower: see Bellows Building.

Construction Steps

1. Build the table. Construct a flat-topped platform approximately 75–85 cm high (waist height for the smith), 90–120 cm wide, and 60–90 cm deep. Stone masonry, stacked brick, or a wooden frame filled with rammed earth all work. The top surface should be roughly level.

   Dimension	Measurement	Notes
   Height	75–85 cm	Match to smith’s waist — reduces back strain
   Width	90–120 cm	Wider = room for larger fires and more tools
   Depth	60–90 cm	Front-to-back; must accommodate firepot + work area
   Firepot diameter	20–30 cm	Smaller = more concentrated heat; larger = bigger work
   Firepot depth	8–12 cm	Deep enough to contain the fire

2. Create the firepot. In the center of the table top (or offset toward the rear), form a shallow, bowl-shaped depression about 25 cm in diameter and 10 cm deep. Line this depression with refractory clay, at least 5 cm thick. This is where the fire burns. Allow the clay to dry thoroughly before first use.

3. Install the tuyere. Run the tuyere pipe through the table wall, entering the firepot from the side at the level of the firepot bottom or slightly above. The pipe should protrude only 2–3 cm into the firepot — further protrusion blocks the fire and gets buried in clinker. Angle the tuyere slightly downward (5°) to prevent clinker from flowing back into the pipe.

4. Add the ash dump (optional but recommended). Below the firepot, create a chamber or opening where clinker and ash can be raked out. In a side-blast forge, this is simply the front of the firepot — you rake debris forward off the table into a bucket.

5. Fire the forge. Before first metalwork use, build several gentle fires in the firepot to cure the refractory clay gradually. Increase fire intensity over 2–3 sessions. Clay that has not been properly cured will crack and spall from thermal shock.

The Chimney/Hood (Important but Optional)

A forge without a hood fills the smithy with smoke, making work uncomfortable and unhealthy. A simple hood and chimney dramatically improve the workspace.

• Build a conical or pyramidal hood from sheet metal (if available) or clay-plastered wicker, positioned 60–90 cm above the firepot.
• Connect to a chimney (stone, brick, or clay pipe) that extends above the roofline.
• The chimney creates natural draft that pulls smoke upward even without a fan.
• If building materials are limited, simply position the forge near a wall opening or under an open-sided roof.

The Anvil

The anvil is the second most important piece of equipment after the forge itself. It is the surface against which all forging, cutting, and shaping occurs.

Ideal Anvil

A proper blacksmith’s anvil is a heavy block of hardened steel with a flat face, a horn (pointed projection for bending), a hardy hole (square hole for inserting tools), and a pritchel hole (round hole for punching through). Weight: 50–150 kg.

If you find a commercial anvil in salvage, it is one of the most valuable items in a rebuilding scenario. Protect it — do not use it as a chopping block or welding table.

Improvised Anvils

Material	Weight Needed	Suitability	Notes
Railroad rail (upright)	15–30 kg per section	Good	Wide, flat top surface; mount on a stump
Large steel plate (3+ cm thick)	30+ kg	Good	Bolt to a heavy stump or concrete block
Heavy I-beam section	20–40 kg	Moderate	Narrow working surface but functional
Large flat stone (granite/basalt)	50+ kg	Poor	Breaks eventually; no rebound; emergency only
Hardwood stump	30–50 kg	Poor	Only for light copper/brass work

The critical quality of an anvil is mass and rigidity. When you strike hot metal on the anvil, the anvil must not move or flex — all the hammer’s energy must go into deforming the workpiece, not bouncing the anvil. Heavier is always better. Mount any improvised anvil on the heaviest, most stable base you can manage — a green hardwood stump set into the ground is traditional.

Anvil Height

Set the anvil face at knuckle height when the smith stands with arms relaxed at their sides. This allows the most efficient hammer swing with the least fatigue. Too high causes wrist strain; too low causes back strain.

Essential Tools

You need surprisingly few tools to begin forging. The basic kit can be made from salvaged materials using only the forge, anvil, and each other.

Must-Have (Day One)

1. Cross-peen hammer (1–1.5 kg): your primary forging tool. One flat face for general work, one wedge-shaped peen for drawing out. Can be salvaged from any hardware store or made from a heavy bolt head.

2. Tongs (at least 2 pairs): hold hot metal. You need at least flat-jaw tongs (for flat bar) and wolf-jaw or V-bit tongs (for round bar). Forge from 12–15 mm round bar — tong-making is an excellent first project.

3. Hot cut (hardy tool): a chisel that fits in the anvil’s hardy hole, edge up. Place hot metal on the edge and strike to cut. Forge from a piece of medium-carbon steel or a large bolt.

4. Punch: a tapered tool for making holes. Forge from a coil spring or high-carbon bolt.

5. Wire brush: for cleaning scale from hot metal. Salvage or make from fine wire bound to a handle.

6. Quench bucket: any container holding at least 20 liters of water, positioned within arm’s reach of the anvil.

Build Next (Week One)

• Straight-peen hammer (0.8–1.2 kg): for spreading metal in a controlled direction
• Flatter: a flat-faced tool with a handle, struck with a hammer, for smoothing surfaces
• Fuller (top and bottom): rounded tools for creating grooves and necking down
• Drift: tapered mandrel for sizing holes — essential for axe and hammer eyes
• Hardie: a cutting tool that fits in the hardy hole; like a hot cut but for heavier work
• Swage block: a heavy plate with various shaped grooves and holes for forming — a luxury but enormously useful

Forge Fire Management

Knowing how to manage the forge fire is as important as any forging technique.

Fuel

Charcoal is the ideal fuel for a beginner’s forge:

• Clean-burning, low sulfur (sulfur ruins iron)
• Available by making your own from any hardwood
• Reaches forging temperature easily with moderate air
• Produces minimal clinker

Coal (mineral coal) is superior in heat output and burn duration but has drawbacks:

• Must be low-sulfur “blacksmithing coal” (bituminous)
• High-sulfur coal makes iron “hot-short” (brittle at red heat)
• Produces clinker (fused ash) that must be regularly cleared from the fire
• Requires coke-making: fresh coal must be coked (heated until volatiles burn off) before it becomes useful forge fuel

Building and Maintaining the Fire

1. Start with a small kindling fire in the firepot. Add charcoal gradually.
2. Begin bellows operation once the charcoal is well lit.
3. Build the fire shape: mound charcoal around and over the fire, leaving an opening at the top for inserting the workpiece. The fire should be roughly hemisphere-shaped, 15–20 cm across.
4. The sweet spot is just above and slightly behind the tuyere opening, where air meets fuel. This is where temperature is highest — position your workpiece here.
5. Bank unused areas: push unlit charcoal up against the edges of the fire. It preheats and catches as the fire consumes fuel from the center.
6. Clinker management (coal fires): periodically rake clinker out of the firepot. Clinker blocks the tuyere and smothers the fire. A clinker breaker (a bent iron rod) pushed through the tuyere from outside clears blockages.

Fire Types for Different Operations

Operation	Fire Type	Air Blast	Notes
General forging	Open, medium	Moderate, steady	Standard operating fire
Forge welding	Deep, closed	Strong	Pack fuel over work to create reducing atmosphere
Heat treatment	Small, clean	Light	Precise, even heat; avoid overheating
Carburization	Deep, reducing	Minimal	Bury work deep in charcoal; lazy, smoky fire
Brazing/soldering	Very small	Gentle	Focused heat on joint only

Workshop Layout

Arrange the forge space for efficient workflow:

• Forge at the back wall (near chimney/ventilation)
• Anvil within one step (arm’s reach) of the forge, positioned so the horn points left (for a right-handed smith)
• Quench bucket between forge and anvil, accessible from both
• Tool rack on the wall behind or beside the anvil — tongs, hammers, and punches within arm’s reach
• Vise mounted on a heavy post or bench, near the anvil but not blocking the workflow
• Stock rack along a wall for iron bar, rod, and plate storage
• Work area in front of the anvil, clear of obstructions — the smith needs room to swing and maneuver long pieces

The floor should be earth, stone, or concrete — never wood. Hot scale and dropped pieces will start fires on wooden floors. Keep the floor clear of debris and trip hazards. A tired smith carrying a piece of orange-hot iron does not need obstacles.

Safety Essentials

• Leather apron: protects from sparks, scale, and radiant heat
• Safety glasses or clear goggles: hot scale flies unpredictably
• Leather gloves (for handling near-heat, NOT for hammer work — gloves reduce grip)
• No synthetic clothing near the forge — polyester melts into skin
• Fire extinguisher or sand bucket within reach
• First aid kit with burn treatment supplies