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Arc Welders
What are Arc Welders?
Arc
welders use a welding power supply to create an electric arc between an
electrode and the base material to melt metals at the welding point.
They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes.
The welding region is sometimes protected by some type of inert or semi-inert gas, and filler material is sometimes used as well.
Reviews, articles, and resources for arc welders
The electric arc welder is one of our most useful and timesaving pieces of shop equipment. Almost every shop, farm, ranch, garage, tech school, or large maintenance department is equipped with one or more arc welders which are used for fabrication, repair, and/or educational programs.
Most of these arc welders are AC/DC, 240 volt transformer types using electricity as the energy source.
Portable arc welders are usually powered by diesel or gasoline engines. Properly installed and used the arc welder is very safe, but if used improperly the operator can be exposed to a number of hazards including toxic fumes, dusts, burns, fires, explosions, electric shock, radiation, noise, and heat stress.
Selecting an ARC welder
When purchasing an arc welder you can be assured of design safety if the unit complies with National Electric Manufacturers Association (NEMA) standards or the safety standards for arc welders as determined by the Underwriters Laboratories (UL). Be sure that the welder you purchase carries the seal of approval of one of these organizations.
According to the Wikipedia, Arc welding processes use a welding power supply to create an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-cosumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, and filler material is sometimes used as well.
Installing Arc Welders
Prior to installing the arc welder you should determine if your present electrical system is adequate to handle the increased power load needed by the welder. If you aren't sure, hire a qualified electrician to safely and properly wire your arc welder.
It is very important for your safety to install the welder in compliance with state, federal and local safety (OSHA) regulations and the National Electric Code (NEC).
The following rules are not a complete list but are especially important guidelines, which should be adhered to:
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The arc welder's frame or case of the welder should be properly grounded.
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A safety-type disconnecting switch or controller should be located near the arc welder
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The arc welder or welders shall be protected by a properly sized fuse or circuit breaker on an independent circuit.
Arc Welders Ventilation
The arc welder should be located in an area with adequate ventilation. In general, when welding is being done on metals not considered hazardous, a ventilation system that will move a minimum of 2000 cubic feet per minute of air per arc welder. However, many materials are considered very hazardous and should be welded only in adequately ventilated areas. See your arc welder specifications or consult a ventilation expert to be sure your arc welder is properly ventilated.
Materials included in the very hazardous category are welding rod fluxes, coverings, or other materials containing fluorine compounds, zinc, lead, beryllium, admium, and mercury.
Arc Welder Fire Protection
Arc welders are capable of producing temperatures in excess of 10,000 degrees Fahrenheit, so your arc welding area must be fire safe.
You can do this by using metal sheets or fire resistant curtains as fire barriers. The floor should be concrete or another fire resistant material. Fill cracks in the floor to prevent sparks and hot metal from entering. When arc welding can't be moved to a fire-safe area then the area should be made safe by removing or protecting combustibles from ignition sources. Fire extinguishing agents should always be available during arc welding. The extinguisher should be large enough for the situation with a 10# size adequate for most farm and school shops. For more information, see our article on arc welder safety.
Arc Welders: Personal Protection
It is essential that the operator and helpers be properly clothed and protected because of the heat, ultra-violet rays, and sparks, produced by arc welders
For body protection a pair of fire retardant long sleeved coveralls without cuffs is a good choice. Always avoid clothing with tears, snags, rips, or worn spots as these are easily ignited by sparks. The sleeves and collars should be kept buttoned. The hands should be protected with leather gauntlet gloves. A pair of high top leather safety shoes, is good protection for the feet. If low shoes are worn the ankles should be protected by fire resistant leggings. Eyes should be protected by transparent goggles if the person wears prescription glasses or safety glasses if not. A welding helmet or hand shield with filter plate and cover plate is mandatory for eye protection from the harmful rays of the arc.
Arc Welders Safe Operations
Anyone who uses an arc welder should be properly trained.
If possible, work to be welded should be placed on a firebrick surface at a
comfortable height. Don't arc weld directly on a concrete floor. Heat from the
arc can cause steam to build-up in the floor which could cause an explosion. The
welder cables should be positioned so that sparks and molten metal will not fall
on them. They should also be kept free of grease and oil and located where they
will not be driven over. If the welding operation must be done on steel or other
conductive material use an insulating mat must be used under the operator.
It is easier and safer to establish an arc on a clean surface than a dirty or
rusty one. Therefore, metal should always be thoroughly cleaned by wire brushing
or other method prior to welding. When chipping slag or wire brushing the
finished bead the operator should always be sure to protect his eyes and body
from flying slag and chips.
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