Kemppi MasterTig LT 250 Operating Manual

Also see for MasterTig LT 250: Quick guide

Contents

EN3. USENOTE! Welding fumes may be dangerous to your health. Ensure that there is ample ventilation duringwelding! Never look at the arc without a face shield specifically designed for arc welding! Protectyourself and your surrounding area from the arc and hot welding spatter!Prepare to weldNOTE! Always wear protective clothing, gloves, face and eye shields suitable for welding. It isrecommended that you make practice welds before you commence welding your main work piece. Ifwhen igniting the arc or during welding, the electrode stick’s or freezes’ to the work piece, note that itwill quickly heat up, and may start to glow red hot. To release the electrode, twist the electrode holderaway from the work piece and start again. If this fails, switch off the machine at the main switch andthen release the electrode after it has cooled down.NOTE! The electrode and work piece will be very hot. Protect yourself and others at all times.You can start welding after you have made the necessary preparation described throughout theseinstructions.3.1 TIG weldingTIG welding electrodes and gas nozzlesIn DC TIG welding we recommend the use of the WC20 (grey) type electrode, however other typesare available.The welding electrode size (diameter) is selected depending on the welding current/power to beused. An electrode with an insufficient diameter compared to the welding current will melt, whileexcessive electrode size will make it more difficult to ignite the arc.Generally speaking, a 1.6 mm tungsten electrode will cover currents up to 150 A, and 2.4 mmtungsten electrode up to 250 A DC current.Before use, grind the tungsten electrode to a sharp point at approximately 1.5 times the diameterof the electrode. If the electrode touches the work piece during welding, re-sharpen the electrode.7© Kemppi Oy / 1422