TODO: Confirm the exact model number from the unit label before publishing. Common ToAuto electric models include the TGF3000-V1.1 (3 kg capacity, 1400W) and the TAF8000 (8 kg capacity, 1800W). Fill in the confirmed specs below.
Model
[TODO: confirm model number from unit label — e.g., TGF3000-V1.1 or TAF8000]
Type
Electric resistance furnace — PID temperature-controlled
Power
[TODO: confirm — 1400W (most 3 kg models) or 1800W (8 kg model)]
Supply Voltage
110V / 60 Hz — standard US outlet
Max Temperature
1,100°C (2,000°F) for most electric models
Crucible Capacity
[TODO: confirm — typically 1–3 kg or up to 8 kg depending on model]
Temperature Control
PID digital controller — monitors and corrects every few seconds
Heat-Up Time
Approximately 40–60 minutes to reach working temperature at full load
Crucible Material
99.95% graphite — included with unit
Inner Chamber
Quartz or alumina lining — heat-resistant, acid/alkali-resistant
The smelting furnace is used to melt metals for casting — pouring molten metal into molds to create ingots, jewelry, art pieces, or functional metal parts. Common uses at the space include:
Casting ingots from scrap metal (aluminum, copper, brass, silver)
Jewelry making — casting rings, pendants, and other small metal pieces
Reclaiming and recycling scrap metal into usable stock
Prototyping metal parts via sand casting or investment casting
This is one of the most hazardous pieces of equipment in the space. Molten metal at 1,000°C+ can cause catastrophic burns on contact, and moisture near molten metal can trigger violent steam explosions. Training and strict PPE compliance are non-negotiable.
Working with molten metal is among the most dangerous activities in any makerspace. Burns from molten metal are almost always severe. Steam explosions from moisture contact can be lethal. Read every rule in this section before you touch the furnace.
Wear all of the following before the furnace is powered on. There are no exceptions and no partial substitutions.
Face shield (full face, IR/UV rated) — protects against molten splatter, infrared radiation, and flash. A face shield is not optional — safety glasses alone are not sufficient when pouring or handling the crucible
Safety glasses should also be worn under the face shield as a backup — the shield can shift
Heat-resistant foundry gloves — must reach at least mid-forearm. The gloves included with the ToAuto unit are a minimum — heavier welding or foundry gloves are strongly recommended for pouring
Never wear gloves made from synthetic materials (nylon, polyester, latex) near molten metal — they melt and fuse to skin
Flame-resistant or natural fiber clothing — cotton, wool, or denim. No synthetics anywhere on your body including inner garments — synthetics melt and cause far worse burns than they would protect against
Leather boots or heavy work shoes — closed-toe, covering the ankle. Molten metal runs downhill; protect your feet
Leather apron or foundry jacket — covers your torso and upper legs against radiant heat and splash
No loose clothing, open cuffs, open pockets, or dangling items — molten metal can collect in folds, cuffs, and open pockets and is impossible to remove quickly
¶The Single Most Important Safety Rule — Keep Everything Dry
⚠ Moisture + molten metal = violent steam explosion. Even a drop of water or a damp tool introduced to molten metal can cause an explosive eruption that throws molten metal in all directions. Moisture is the number one cause of serious injuries and fatalities in foundry operations.
Pre-heat all tools (tongs, molds, skimmers, ladles) before they contact molten metal — hold them near — but not in — the furnace for several minutes to drive off any surface moisture
Pre-heat all metal charge material by placing it near the warm furnace for several minutes before adding it to the crucible — never drop cold or wet metal into molten metal
Never pour molten metal onto a wet or damp surface — the work surface must be completely dry
Never pour molten metal onto concrete without a dry sand bed beneath your mold — moisture trapped in concrete causes concrete to explode
Molds must be completely dry and pre-warmed before receiving molten metal — a wet mold will explode
Do not pour molten metal in rain, high humidity, or outdoors during damp conditions
Melting metals produces metal fumes and oxide particles — ventilation is mandatory
Run the space's ventilation system before starting and keep it running throughout the session and for several minutes after
⚠ Zinc fumes are particularly hazardous — even brief exposure causes metal fume fever (flu-like illness lasting 24–48 hours). Zinc is present in galvanized steel, die-cast parts, and some brass alloys. Never melt galvanized, zinc-coated, or unknown scrap metal without confirming the composition first.
⚠ Lead is highly toxic — do not melt lead or any lead-containing alloys in the space. Lead fumes accumulate in the body and cause permanent neurological damage.
⚠ Cadmium (present in some older solders and coatings) is carcinogenic even at low doses. Do not melt unknown solder or cadmium-plated materials.
A respirator with P100 particulate filters is recommended when working with any metal fumes, especially during skimming or pouring
Never melt painted, coated, or plated metals without first confirming the coating is non-toxic — many industrial coatings contain chromium, zinc, or cadmium
Inspect the graphite crucible before every use — look for cracks, chips, or thinning walls. A cracked crucible can fail catastrophically mid-melt, releasing molten metal inside the furnace
Never use a cracked or damaged crucible — replace it. Replacement crucibles are [TODO: stocked at / ordered from location]
Always use the correct crucible tongs — the groove on the crucible rim is specifically designed to interlock with the tongs. Do not attempt to lift or pour with improvised tools
Never overfill the crucible — maximum fill is approximately 80% to allow for expansion and prevent overflow when metal melts
When removing the crucible from the furnace for pouring, keep it close to your body and move slowly and deliberately — no sudden movements
Use a dedicated, non-combustible work surface for the furnace and pouring — a steel or ceramic table is ideal. Avoid wooden benches for the furnace itself
Cover the floor beneath the pouring area with a dry sand bed or steel drip tray — molten metal on a concrete floor causes the concrete to explode
Keep the work area clear of trip hazards — a stumble while carrying a crucible of molten metal is catastrophic
Have a clear, unobstructed path from the furnace to the pouring area — plan your route before the melt begins
Post-pour spills happen — know where to set the crucible quickly if a pour goes wrong
No unauthorized people near the furnace while it is running or while pouring. Only the trained operator and their spotter should be in the immediate area
The furnace draws 1,400–1,800W continuously — confirm the outlet and circuit can handle sustained load. Do not share the circuit with other high-draw equipment during operation
Connect to a grounded outlet only
Do not operate with wet hands or in damp conditions
Do not leave the power cord where it can contact the hot furnace body
If the PID controller malfunctions or the furnace runs above the set temperature without correction, power off immediately and report to [TODO: equipment lead]
The electric ToAuto furnace has a maximum temperature of 1,100°C (2,000°F). Only metals with a melting point below this threshold can be processed. The table below shows common metals and their suitability.
Metal
Melt Temp
In Range?
Notes
Aluminum
660°C / 1,220°F
Yes — preferred
Easiest and safest metal for beginners. Low melting point, widely available. Aluminum cans, engine parts, and extrusions all work well.
Zinc
419°C / 786°F
Yes — with care
Low melting point but produces toxic fumes. Ventilation and respirator are mandatory. Never melt galvanized steel (zinc-coated).
Tin
232°C / 449°F
Yes
Very low melting point. Easy to work with. Used in pewter and bearing alloys.
Lead
327°C / 621°F
PROHIBITED
Highly toxic — permanently banned from use in the space. Lead fumes accumulate in the body and cause irreversible neurological damage.
Silver (pure)
961°C / 1,762°F
Yes
Melts within range. Commonly used for jewelry. Use clean silver stock — contaminated silver can produce unexpected fumes.
Copper (pure)
1,085°C / 1,985°F
Marginal
Right at the limit of the furnace's maximum temperature. May not reach full melt under all conditions. Check with lead before attempting.
Gold
1,064°C / 1,947°F
Yes
Melts within range. Jewelry applications.
Brass/Bronze
900–1,050°C
Yes — with care
Copper alloys. Melts within range but produces zinc and copper oxide fumes — strong ventilation and respirator required.
Iron / Steel
1,370°C+ / 2,500°F+
NO
Far above the furnace's maximum temperature. Cannot be melted in this unit.
Unknown scrap
Unknown
PROHIBITED
Never melt unidentified scrap. Unknown alloys may contain lead, cadmium, zinc, beryllium, or other toxic materials.
⚠ Lead is permanently prohibited. No exceptions, no small amounts, no lead solder. Lead fumes are invisible, odorless, and cumulative — there is no safe exposure level in a shared space.
⚠ Never melt galvanized, zinc-coated, chrome-plated, cadmium-plated, or painted metals without confirming the coating composition. Industrial coatings frequently contain toxic heavy metals.
⚠ Do not melt unidentified scrap metal. If you don't know exactly what it is, don't put it in the furnace.
Allow castings to cool naturally — do not quench in water (thermal shock can crack both the casting and the mold)
Aluminum: allow at least 10–15 minutes before handling with gloves
Copper, silver, brass: allow longer — these retain heat more than aluminum
Use tongs to handle any casting that may still be warm — do not trust appearance alone; metal that looks solidified can still be hot enough to cause burns
Inspect castings for completeness — incomplete fills may indicate the metal cooled too quickly or the mold wasn't hot enough
Clean the crucible while warm — remove dross and metal residue with a wire brush
Inspect the crucible for cracks, chips, or thinning — do not use a damaged crucible
Wipe down the furnace exterior and work area
Inspect the furnace chamber interior for metal spills or buildup — report to [TODO: lead] if significant material has accumulated on the heating elements or chamber walls
Log any issues, unexpected behavior, or material consumed on the session log at [TODO: location]
Power off immediately. Do not continue the melt. Report to [TODO: lead] — this indicates a sensor or controller fault.
Metal not melting at expected temperature
Crucible may be underfilled (metal needs thermal mass) or furnace needs more time. Ensure lid is closed. Check that correct temperature is set.
Smoke or fumes from the furnace
Check metal composition — some alloys produce more fumes than others. Increase ventilation. If smell is sharp or chemical, power off and evacuate area.
Crucible appears to be leaking
E-stop immediately — do not attempt to remove a leaking crucible. Molten metal inside the furnace is extremely dangerous. Contact [TODO: lead].
Metal splatter during charge or pour
Metal was wet or cold when added. Pre-warm all materials thoroughly before adding to melt. Slow down the pour rate.
Casting has voids or incomplete fill
Mold may have been too cold (pre-warm longer), metal may have been too cold (increase temp or pour faster), or pour rate was too slow.
Furnace exterior is very hot to touch
Normal during operation — maintain clearance. If exterior is hot enough to ignite materials nearby, increase clearance and check for chamber lining damage.
PID temperature won't stabilize
Lid may not be properly seated. Check that crucible is not touching the heating elements. Report to [TODO: lead] if persistent.
In-person training with [TODO: furnace lead — confirm who owns this equipment at the space] is required before solo use
Training covers: PPE requirements, moisture hazard rules, approved and banned metals, furnace operation, pouring technique, fire response, and shutdown procedure
Prior metalworking experience does not substitute for space-specific training — the moisture explosion risk in particular requires hands-on demonstration
Two-person rule strongly recommended for all pours — one operator, one spotter who is also in full PPE and knows the emergency procedures
Training sign-off recorded at [TODO: location or link]