SAFETY DISCLAIMER: READ BEFORE YOU BUY, BUILD OR FIRE

Furnace V1 (waste-oil, aluminium/brass) — Rev B design package, NOT YET FIELD-BUILT.

This design has never been built, fired or tested by ScrapBuilt or anyone else. It is a paper design that was checked only by two automated (AI-run) design reviews, not by a licensed engineer or a real build. Every performance figure in it (temperatures, melt times, fuel and air flows, shell temperatures, lifting limits, costs) is a calculated estimate, not a measurement. The fix register lists 9 open risks that need physical verification: flame-sensor behaviour on hot restart; cold-oil gravity feed margin; lining and lid-anchor temperatures with no margin at brass duty (brass is "feasible but marginal"); the hand-built tongs/shank rating (proof test required); lid-lift clearances; the purchased castable's rating and dry-out schedule; aluminium charging requiring a full shutdown/restart each time; scavenged compressor/blower performance and all prices; and stick-welding thin sheet. Expect errors. Rev C will follow a real build.

This is not professional engineering advice. The plans are not prepared, sealed or reviewed by a licensed professional engineer. The burner, fuel system, controls, lifting gear and pressure parts are not certified, listed or approved by UL, CSA, ASME, NFPA or any authority, and do not claim compliance with any code or standard.

Hazards you accept by building or using this design

An oil-fired crucible furnace combines a flammable liquid, open flame, surfaces above 1000 °C and molten metal. Mistakes can kill or maim you and bystanders and can burn down buildings.

• Fire and explosion: use only filtered used engine oil from a known, traceable source. Used oil can contain fuel and solvents with a flash point below room temperature. Leaks, spills, pooled oil, flame-out and relighting can cause pool fires, flashback, or a delayed-ignition explosion ("whoomph") that blows flame out of the furnace at the operator.
• Carbon monoxide and toxic fumes: combustion produces CO, which is odourless and lethal. Burning used oil and melting coated or contaminated metal releases toxic smoke, metal fume and other pollutants. Outdoors only. Never in a garage, shed, basement, tent, carport or any enclosed or partly enclosed space. A personal CO alarm is required; a dust respirator does not protect against CO.
• Molten metal: spills, crucible failure, or contact with water or damp tools, moulds, ground or scrap causes steam explosions that throw molten metal. Severe burns, blindness and death are possible. Never pour over concrete or wet ground.
• Burns and hot surfaces: the shell, lid, flue, burner and tools stay dangerously hot long after shutdown.
• Electrical: mains-powered controls near fuel and wet ground can cause shock or ignition.
• Lifting and crushing: the lid, crucible and tools are heavy and can fall.
• Refractory dust and ceramic fibre: harmful to lungs; follow the product datasheets.
• Environmental and legal: used oil and combustion emissions are regulated in many places. Burning used oil may be illegal where you live.

Builder assumes all risk

By buying, downloading, building, modifying or operating anything from these plans, you accept full and sole responsibility and all risk of injury, death, property damage, fire, environmental harm and legal consequences, for yourself and anyone near your build. You are responsible for your own competence, judgement, supervision, protective equipment, fire precautions, site safety and compliance with local laws, permits, codes, fire and air-quality rules and your insurance terms. If you are not experienced with welding, fuel-fired equipment and molten metal, get qualified, in-person help, or do not build this.

ScrapBuilt, its owner and contributors make no warranty of any kind and accept no liability for any loss or harm arising from these plans or anything built from them, to the fullest extent permitted by law (see the Terms, §8–9).

If any instruction seems unsafe for your situation, stop. Nothing in the plans overrides your own judgement, a qualified person inspecting your actual build, or the law.