Using the Arc Welder
The arc welder is used for welding or joining
two or more pieces of metal together. The metal is
heated to a molten state using electricity which
creates an arc. Either AC or DC is used and a
welding rod appropriate to the metals being used.
The two pieces of metal are heated to a molten
state and are fused together as the metals blend
and a compatible welding rod is melted and used as
Controls: The controls on
the arc welder in the materials processing laboratory
consist of the following:
- Amperage of the welder is adjusted for the electrode
being used. Other welders allow adjustments for polarity;
AC or DC or DC reverse.
- Welding rod is selected based upon the material to be
welded, the position of the weld, and the penetration
into the metal that is needed.
Operation: Welding heats metal
and using a filler rod, joins two pieces of metal. Refer to
the following illustrations.
- Clean the metal that is to be welded. It should be
free of dirt, impurities and flammable materials.
- Adjust the arc welder to the correct setting for the
material and rod being used; AC or DC polarity.
- Connect the ground clamp to the work piece.
- Select the proper welding rod for the metal being
welded. Place into rod holder.
- Strike an arc by quickly tapping the welding rod to
the work piece or by quickly scratching it across the
- Maintain the arc length equal to the diameter of the
- Maintain an angle of 15 degrees off vertical with the
- Use a chipping hammer to remove slag from the
Stock is being fed into the planer. Notice that
the worker is wearing welding helmet for eye
The weld is being cleaned of slag with a slag
hammer which forms as the piece is welded.
Potential hazards: The
following hazards exist:
- Materials become hot during welding. Care must be
used to avoid touching hot metals.
- Sparks are created avoid contact with flammable
- Eyes may burn when looking at the arc. Use a welding
helmet with shade 9 glass.
- A sunburn-type burn is possible on exposed skin;
cover arms and neck.
Safety practices: Because
of those potential hazards the following safety rules must
- Eye protection required. The ultra-violet and
infra-red rays which are given off during arc welding
will burn the eyes. A shade 9 must be used in the
- Eye protection must be worn when chipping flux and
when cleaning with the wire brush.
- Electrocution is a possibility with the use of
electricity. Avoid standing in puddles or welding while
standing on damp ground.
- Do not touch welded metals as they are hot.
- Leather gloves and an apron protect from sparks.
- Wear long sleeves and closed shirt collar to protect
arms neck from intense light, spatter and sparks.
- Do not wear particularly flammable clothing such as
chamois and nylon.
- Tie back long hair.
Graham, Gregory S. (1981). Metalworking : an
Introduction. Boston, Mass. : Breton Publishers. p.
Walker, John R. (1972). Exploring Metalworking; Basic
Fundamentals. South Holland, Illinois: The Goodheart-Willcox
Co. p. 125-131.
Zaner, John. (9/9/01). Circular Saw.
ITT 252 - Materials Processing
Department of Technology
University of Southern Maine
Prepared by Joanne Gauley, 11/15/2001