Charcoal & Coal Forges: Solid Fuel, the JABOD, and Fire Management

Propane won the convenience war (first-forge guide), but solid fuel — charcoal and coal — still owns three things: the lowest cost of entry in all of smithing, a fire that concentrates savage heat exactly where you build it, and the full sensory tradition of the craft. If “forge” to you means glowing coals and rising sparks, or your budget says $30 and a shovel, this is your path.

The JABOD: Forging for the Cost of Lunch

The beloved community starter design is literally called a JABOD — “Just A Box Of Dirt” (born on the I Forge Iron forums): a wooden box or steel container packed with plain dirt or clay-sand, a trench shaped into the top, and a pipe entering from the side for air. Charcoal in the trench, air through the pipe — hair dryer, mattress inflator, or hand-crank blower — and that’s a forge that reaches forging (and with practice, welding) heat. Cost: near zero. Build time: an afternoon. It is not a toy; makers forge real blades on JABODs every day, and it teaches fire management better than any burner knob ever will.

Charcoal vs. Coal, Honestly

• Lump charcoal (real hardwood lump, never briquettes — those are compressed filler that smothers a fire): clean-burning, easy to light, available at any big-box store, historically what most of the world’s blades were forged with. Burns fast — you’ll feed the fire steadily — and throws fleas (sparks), so mind the surroundings. Community consensus: the friendliest solid fuel, and welding-friendly with an ash-clean fire.

  

• Bituminous smithing coal / coke: hotter and longer-burning per pound, the professional choice for heavy forging. Costs: real smithing coal takes finding (blacksmith suppliers or association group buys), lights grudgingly, smokes seriously until it cokes up, and its smell announces your hobby to the zip code. Better economics per-hour once you’re feeding a working fire.
• Rule of thumb: suburban and starting = charcoal; rural and forging often = coal earns its logistics.

Fire Management: the Actual Skill

1. Build deep, not wide. The sweet spot sits in the heart of the fire — steel wants 2–4″ of glowing fuel below it and a mound above; a shallow fire oxidizes steel in cold air while looking hot.

   

2. Air is your throttle. More blast = hotter and faster-burning (and, past reason, a scale factory and burnt corners — see cracks after forging). Learn the light touch: steady modest air for soak, a push toward welding heat, near-nothing while you’re at the anvil.
3. Keep house as you work: rake fresh fuel inward from the edges so it pre-heats and cokes, pluck clinker (the fused glassy ash that chokes the air inlet) when the fire goes sluggish, and park your next bar warming at the fire’s edge like the old-timers.

   

4. Heat treating too: a well-managed solid fire runs the whole no-kiln heat treat — the deep-fire even soak arguably beats a torch for it.

What You Give Up

Push-button convenience, indoor use (solid fuel is an outdoor/serious-ventilation game — CO and smoke both), consistent atmosphere (a lazy fire eats more steel to scale than a tuned gas forge), and neighbors’ goodwill if it’s coal. What you gain: the cheapest working forge on earth, the hottest spot heat you’ll ever park a billet in, and the craft’s original soundtrack. Plenty of smiths run both — gas for production, solid fuel for the soul of it.

Sources

• I Forge Iron — home of the JABOD build threads
• BladeForums — lump charcoal vs smithing coal
• Storm the Castle — coal vs hardwood charcoal comparison