Thermal Arc ARCMASTER 300 MST User Manual (English)

Questions and Answers:

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Jessica KnappAug 6, 2025
What to do if Thermal Arc ARCMASTER 300 MST Welding System has lack of penetration?
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  Denise SandersAug 6, 2025
  If your Thermal Arc Welding System is showing a lack of penetration, consider these factors: * Welding current: If it’s too low, increase it by increasing the wire feed speed and the WELD (V) control. * Joint preparation: If the joint angle is too narrow or the gap is too tight, increase the joint angle or gap. * Shielding gas: If it’s incorrect, switch to a gas that provides higher penetration.
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Allison JohnsonAug 13, 2025
How to prevent weld cracking in Thermal Arc ARCMASTER 300 MST?
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  stephensjenniferAug 13, 2025
  If you're experiencing weld cracking with your Thermal Arc Welding System, consider the following: * Weld beads: If they are too small, decrease the travel speed. * Weld penetration: If it's narrow and deep, reduce current and voltage, increase MIG torch travel speed, or select a lower penetration shielding gas. * Weld stresses: If there are excessive weld stresses, increase weld metal strength or revise the design. * Voltage: If there is excessive voltage, decrease it by reducing the WELD (V) control. * Cooling rate: If it’s too fast, slow it down by preheating the part to be welded or allow it to cool slowly.
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Robyn EdwardsAug 18, 2025
How to fix porosity in Thermal Arc Welding System?
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  Karen SchroederAug 18, 2025
  To fix porosity in your Thermal Arc Welding System, take the following steps: * Ensure your gas cylinder isn't empty and the flow meter is correctly set to 25 cubic feet per hour. * Check for gas leaks from the regulator/cylinder connection to the gas hose at the wire feeder. * Make sure the hose from the solenoid valve to the MIG torch adapter isn't fractured and is properly connected. * Shield the welding area from wind or increase the gas flow. * Clean contaminants off the plate. * Keep the distance between the MIG torch nozzle and the workpiece minimal. * Ensure gas holes aren't blocked and gas exits the torch nozzle; prevent spatter buildup inside the nozzle and check the MIG torch O-rings for damage.

Thermal Arc ARCMASTER 300 MST Specifications

General

Input Frequency	50/60 Hz
Output Current Range	5-300 A
Duty Cycle	60% at 300 A
Protection Class	IP23
Welding Processes	TIG
Open Circuit Voltage	70 V
Input Phase	1-Phase/3-Phase
Rated Output	300 A @ 32 VDC
Weight	66 lbs (30 kg)