Jasic MIG 250C, Operator'S Manual

Page: 39 / 50

39
TIG WELDING PROBLEMS
Before starting any welding activity ensure that you have suitable eye protection and
protective clothing. Also take the necessary steps to protect any persons within the welding
area.
TIG welding defects and prevention methods
Defect Possible cause Action
Excessive tungsten use Set up for DCEP Change to DCEN
Insufficient shield gas flow Check for gas restriction and correct flow
rates. Check for drafts in the weld area
Electrode size too small Select correct size
Electrode contamination during
cooling time Extend post flow gas time
Porosity/weld contamination Loose torch or hose fitting Check and tighten all fittings
Inadequate shield gas flow Adjust flow rate - normally 8 - 12L/m
Incorrect shield gas Use correct shield gas
Gas hose damaged Check and repair any damaged hoses
Base material contaminated Clean material properly
Incorrect filler material Check correct filler wire for grade of use
No operation when torch
switch is operated Torch switch or cable faulty Check the torch switch continuity and
repair or replace as required
ON/OFF switch turned off Check position of ON/OFF switch
Mains fuses blown Check fuses and replace as required
Fault inside the machine Call for a repair technician
Low output current Loose or defective work clamp Tighten/replace clamp
Loose cable plug Check and tighten all plugs
Power source faulty Call a repair technician
Will not strike an arc Weld/power cable open circuit Check all cables and connections for
continuity, especially the torch cables
No shield gas flowing Check cylinder contents, regulator and
valves, also check the power source
Unstable arc when welding in
DC Tungsten contaminated Break off contaminated end and regrind
the tungsten
Arc length incorrect Arc length should be between 3 - 6mm
Material contaminated Clean all base and filler material
Electrode connected to the wrong
polarity Reconnect to correct polarity
Arc is difficult to start Incorrect tungsten type Check and fit correct tungsten
Incorrect shield gas Use argon shield gas