Arc Welding

Arc welding was the first type of electric welding to be invented, back in the 1940s, and it’s still in widespread use today. You’ll find arc welders being used on a daily basis in a variety of industries, from large shipbuilders to small auto and fabrication shops.

In the decades since it’s invention, many race cars, dragsters, utility trailers, ships and even skyscrapers were successfully built or repaired with transformer powered arc welders. Even many nuclear power stations were constructed with the use of arc welders and low hydrogen welding rods.

Arc welding is the simplest form of electric welding, and one big advantage it has is the extensive selection of welding rods (filler metal), and the fact that these rods are very easy to transport and use. While somewhat difficult to learn, this welding method is still a valuable asset to any small shop or fabrication business, and many things can be welded with the average arc welding arc welder working on oil pipelinemachine.

Arc welding is differentiated from its cousin Mig welding by the fact that it utilizes a flux-coated welding rod typically 12 inches long, whereas Mig welders are wire-fed machines.

The arc welding electrode is a rod constructed of steel, stainless steel, or aluminum and is coated with a flux material that shields the weld pool when welding. This flux is a mixture of oxides, fluorides, carbonates and metal alloys that bind together and around the rod. This flux coating also cleans and protects the hot weld bead as it cools, protecting it from the atmosphere that could degrade the weld.

The electrodes are easy to change, and they can be inserted into the electrode holder fairly quickly. Still, this does slow down the process on bigger welding jobs, which is why many welders prefer to use a wire-fed Mig welding for those applications.

You can stick weld with AC or DC

Stick or arc welding gives you the option of using alternating or direct current. Many welding machines use AC output exclusively, and these are popular welders all around the world. AC welders are often cheaper and easier to manufacture, and cost less to buy, and so welders often choose AC over a DC output machine. And more and more of the new welders offer both AC and DC output, so you can often have the best of both worlds (but expect to pay a higher price for an inverter driven welder).

The other option with arc welding is using a DC or direct current output machine. With this type of welder you can manually choose the polarity, making the welding rod negative or positive as the need requires. Typically the DC machine will have a toggle or rotary switch on the control panel for choosing polarity, or another option is to simply switch over the welding cables. Just make sure the welding rods you’re using are designed to work with DC power output.

Choosing A Welder

 

When shopping for equipment, the best place to start is by determining your welding needs — now and into the future — then choose the arc welder that will meet those needs. Arc welders can range from $100 to $30,000 or more. Most times you won’t want to choose the cheapest unit, but you also probably won’t need the most expensive welder you can find either.

For most shops, a large capacity arc welder just isn’t necessary. In fact, even many commercial welding operations often dial their largest capacity arc welders down to about a third or less of its capacity. So for example a 400 amp machine will be set at 150 amps or less. This also improves the duty cycle – the percentage of time that the welding machine can be operated at its rated output before stopping to cool the machine down.

If you exceed the duty cycle when welding, the machine will start to develop less power than its rated output. For example, one common duty cycle rating is 60% at 200 amps. This means that if the machine is set at 200 amps, it can operate for about 6 out of every 10 minutes. As you might imagine, the duty cycle goes down as the amperage is dialed up, and vice versa.

If you’re looking for a cost-effective arc welder, one choice would be a machine with 80% or 90% duty cycle at 125 amps.

 


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