Microflame soldering unit — MIG-O-MAT Lötstar 141
Out of service. The automatic leak test failed on 10 October 2026 because of a small crack at the edge of the vaporizer glass. Replacement parts were ordered on 12 October. Do not use the machine until it is repaired and cleared.
Microflame soldering unit that makes its own hydrogen/oxygen gas by electrolysis of water. Used for precision soldering and brazing of small parts and jewellery. No gas bottles needed.
MIG-O-MAT Lötstar 141, front view
Location | Silver smithing workshop, soldering corner |
Access | Introduction course required |
Working pressure | 50–150 mbar recommended; 300 mbar is the safety maximum |
Max. nozzle | 1.0 mm |
Power | 230 V, 900 W |
Help | Slack #silversmide |
Introduced in spring 2024 after the propane equipment was removed in autumn 2023. Propane cylinders may not be stored in the silver smithing workshop.
Materials
Solder and flux suitable for the metal. No tin or lead in the workshop.
Solder on charcoal, ceramic or Skamol blocks.
Safety
The gas is highly flammable. The electrolyte is strongly corrosive, and BLQ-1800 is flammable.
Never leave the machine running unattended, and never let gas flow from the torch without a flame.
Never slowly turn the flame down towards the nozzle. Too little gas flow causes flashback.
Don't use the machine if a hose, glass vessel, seal or flashback arrestor is damaged or leaking. Never bypass safety devices.
Stop gas production and release pressure before opening any filling port or vessel. Discharge static first by touching the metal cap nuts.
Wear goggles and chemical-resistant gloves when handling liquids. Don't overtighten glass-vessel fittings, because the glass cracks.
How to use
Start
Check there is no out-of-service notice and that the bench is clear of combustibles.
Check the reactor water level with the glass float. Check the hoses, handpiece and vessels. Torch valve closed.
Turn on the rear mains switch, then press the front I/O button. Follow the display.
Run the automatic leak test each day, with the reactor below 45 °C. It takes about 30 s. Do not continue if it fails.
At operating pressure, check the vaporizer: the liquid must cover the gas distributor and stay below the red mark.
Solder
Set the pressure with the arrow buttons, normally 50–150 mbar. Open the torch valve and light it as shown in the introduction.
In short pauses, put out the flame and close the valve. In long pauses, also stop gas production with I/O.
Shut down
Put out the flame quickly, with an air pulse, a dip in water or by closing the valve fast. Then close the torch valve.
Stop gas production with the front I/O button.
Wait for the cooling fan to stop, then turn off the rear mains switch.
Clean the soldering area and leave hot work where nobody will touch it.
Troubleshooting
Symptom | Action |
|---|---|
Leak test fails / suspected leak | Stop; do not use until fixed |
Weak or unstable flame | Check nozzle, liquid levels and leak test; don't raise pressure to compensate |
Flashback or damaged nozzle | Stop; have the handpiece, nozzle and flashback arrestor checked |
Overtemperature / overload | Close the torch valve, press I/O for standby, leave mains on so the fan can cool it |
Pressure fault or above 300 mbar | Switch off immediately and report |
Chemical spill | Stop, keep ignition sources away, follow the safety data sheet |
Report faults in #silversmide. Do not keep resetting a fault without fixing its cause.
Maintenance
Only do tasks covered in the introduction.
Reactor: check the level daily. Top up with distilled or demineralised water only, never tap water.
Vaporizer: check the level at operating pressure and refill with the machine stopped, never above the red mark. Clean it about once a month.
Drying/filter vessel: drain the condensate when it is more than 1 cm deep. Replace the filter about once a year.
Consumables
Item | Use |
|---|---|
Distilled / demineralised water | Reactor top-up |
Reactor fill; not needed for routine top-ups | |
MIG-O-MAT BLQ-1800 | Vaporizer liquid |
Nozzles, filters, seals | Wear parts |
Spent liquids are chemical waste.
Specifications
Supply | 230 V AC, 50/60 Hz, 900 W |
Gas production | Up to 140 l/h |
Pressure | Adjustable 50–200 mbar, max. 300 mbar |
Max. nozzle | 1.0 mm |
Weight | 25 kg |
Documents and links
Operating manual, English (PDF) — model 141. Safety pp. 4–6, controls pp. 11–14, operation pp. 24–30, maintenance pp. 32–42.
Gallery
Soldering corner
Soldering corner with soldering blocks, rotating supports and the torch holder.
Nameplate side
Side view
Front with handpiece and hose