Miller Electric DB1712RDI25, DB1725RDI25 Guidelines for TIG Welding Gtaw, Positioning The Torch

5-2. Preparing Tungsten Electrode For Welding

YGrinding the tungsten electrode produces dust and flying sparks which can cause injury and start fires. Use

local exhaust (forced ventilation) at the grinder or wear an approved respirator. Read MSDS for safety infor- mation. Consider using tungsten containing ceria, lanthana, or yttria instead of thoria. Grinding dust from thoriated electrodes contains low-level radioactive material. Properly dispose of grinder dust in an environ- mentally safe way. Wear proper face, hand, and body protection. Keep flammables away.

A. Preparing Tungsten For DC Electrode Negative (DCEN) Welding Or AC Welding With Inverter Machines

Radial Grinding

Causes Wandering Arc

Wrong Tungsten Preparation

2-1/2 Times

Electrode Diameter

2 3

1

4

Ideal Tungsten Preparation − Stable Arc

1 Grinding Wheel

Grind end of tungsten on fine grit, hard abrasive wheel before welding. Do not use wheel for other jobs or tungsten can become contaminated causing lower weld quality.

2Tungsten Electrode

3Flat

Diameter of this flat determines amperage capacity.

4 Straight Ground

Grind lengthwise, not radial.

B. Preparing Tungsten For Conventional AC Welding

1 − 1-1/2 Times

Electrode Diameter

1 2

1Tungsten Electrode

2Balled End

Ball end of tungsten by applying AC amper- age recommended for a given electrode diameter (see Section 5-1). Let ball on end of the tungsten take its own shape.

SECTION 6 − GUIDELINES FOR TIG WELDING (GTAW)

6-1. Positioning The Torch

		Y Weld current can damage electronic parts in vehicles. Discon-
			nect both battery cables before welding on a vehicle. Place work
			clamp as close to the weld as possible.
	3	. For additional information, see your distributor for a handbook on the
			Gas Tungsten Arc Welding (GTAW) process.
2		1	Workpiece

1

90°

10−15°

4

5

6

5 6

1/16 in 3/16 in

Bottom View Of Gas Cup

	Make sure workpiece is clean before welding.
4	2	Work Clamp
	Place as close to the weld as possible.
	3	Torch
	4	Filler Rod (If Applicable)
	5	Gas Cup
	6	Tungsten Electrode

Select and prepare tungsten according to Sections 5-1and 5-2.

Guidelines:

The inside diameter of the gas cup should be at least three times the tungsten diameter to provide adequate shielding gas coverage. (For example, if tungsten is 1/16 in diameter, gas cup should be a minimum of 3/16 in diameter.

Tungsten extension is the distance the tungsten extends out gas cup of torch.

The tungsten extension should be no greater than the inside diameter of the gas cup.

Arc length is the distance from the tungsten to the workpiece.

Ref. ST-161 892

OM-1600 Page 10