MIG Welder Buyer's Guide

April 6, 2012

Learn about the difference between a MIG welder and a TIG welder, the MIG welder's features and advantages, and a few basic welding tips.

A MIG welder is used almost exclusively in the auto industry. The process of MIG or metal inert gas welding involves a consumable wire electrode and shielding gas to protect the weld being fed through a welding gun. This differs from TIG welding, which uses a fixed, non-consumable tungsten electrode that produces a high energy arc. The process is rarely used outdoors, due to volatile air quality that will affect the weld, but is common inside a workshop or automotive repair facility.

Level of Experience Working with a MIG Welder

A person interested in purchasing a MIG welder should have some experience with this welding process and have worked on such equipment before. This is not a learn-as-you-go process, since the welding can be both complex and dangerous for a novice. For individuals with the requisite experience, here is a quick buyer's guide to MIG welders.

Cost and Other Considerations

When buying a MIG welder, cost is a consideration but should not be the only one. Buying a cheap MIG welder will result in cheap, inferior welds, while a more expensive model may be too much for your needs. To determine what is appropriate, ask an authorized dealer for information and recommendations.

As an example, if you're welding on a modern car that has thin panels, a small welder should be sufficient. Older cars with a separate chassis would require a 130 amp MIG welder at the minimum. A vehicle like a Land Rover or SUV would require a MIG welder of 150 amps or more. When you are looking for a MIG welder, make sure you keep in mind the use you're going to put it to.

Quality of MIG Welders

The quality of a MIG welder is based on where it's made. Those manufactured in Eastern Europe and China tend to have a lower price, but they are generally of a lower quality, and are often inadequate for your needs. An expensive MIG welder has better electronic components and wire feed units. What you might save in upfront costs will be diminished by other costs associated with blown fuses or replacement of the wire feed unit.

Automatic or Semiautomatic?

There are both kinds of MIG welding machines available. The automatic MIGs contain automatic controls and a robotic arm that manages the welding task once configured. With semiautomatic MIGs, slight human intervention is needed in holding the gun and navigating it. Which of these you want will depend on the cost as well, because automatic MIGs are decidedly more expensive than the semiautomatic ones.

Costs

The occasional welder that needs to perform some spot welding can get by with spending between $300 and $600 for a good quality MIG welder. You could also consider searching online or through bulletin boards such as Craigslist for a good used MIG welder. A used welder that has been appropriately maintained and cared for might be more than sufficient in meeting your needs and come at a price you can afford.

Features to Look for in a MIG Welder

There are various features to look for in a MIG welder. Some of these features include the ease of use of the welding stick and consumable electrode, the portability of the welder and the amps of the MIG welder.

MIG Welder Amps

The weld thickness will determine the amps needed for the MIG welder you are considering. The following shows maximum steel thickness for a butt weld based on amps:

  • 90 amp, 2.0 millimeters
  • 110 amp, 2.5 millimeters
  • 130 amp, 3.0 millimeters
  • 150 amp, 4.0 millimeters
  • 180 amp, 5.0 millimeters

Here are the maximum thickness for a V and root gap weld based on the MIG welders amps:

  • 90 amp, 3.0 millimeters
  • 110 amp, 3.8 millimeters
  • 130 amp, 4.5 millimeters
  • 150 amp, 6.0 millimeters
  • 180 amp, 7.5 millimeters

Portability of the MIG Welder

A MIG welder is more portable to use than a TIG welder, which has a welding plate where metal is placed. The MIG welder should be easy to move where it is needed in order to perform the weld.

Ease of Use

The MIG welder should be easy to use and the wand that contains the consumable electrode easy to operate. A wand that is too cumbersome or bulky will not be as effective as one that has a weld electrode that can be moved simply and easily.

When purchasing a MIG welder, look for one that meets your amp needs, is portable and easy to use. A welding supply store or other type of equipment retailer that sells MIG welders can help you find the machine that is right for you based on the type of usage you have.

Keys to Using a MIG Welder

A MIG welder works through the creation of an arc between the metal being bonded and the wire electrode. The arc creates the weld which is sealed and protected from elements by gas being fed to the arc. A MIG weld generates a lot of heat and electricity and the welder must wear a protective shield to protect his or her eyes.

The Difference between TIG and MIG Welding

TIG welding uses tungsten electrodes. The electrodes do not burn off or dissolve during the welding process. MIG welding uses a wire, which dissolves upon the completion of the weld. MIG welding was developed in the 1940s as a way to bind aluminum and nonferrous metals while TIG welding is used with thin layers of stainless steel, aluminum, copper and magnesium alloys.

Observing Safety Procedures

One of the basics related to MIG welding is the observation of safety procedures. MIG welding uses a stick wand that holds a wire electrode that creates the weld. The welder must maintain a short arc in order for the weld to be effective. Wearing a safety shield and ear plugs and not wearing loose, combustible clothing are essential to a safe working environment when using a MIG welder.

Feeding the Wire for the Weld

The wire electrode used in a MIG welder should be carefully guided into an acceptable position within the welding wand. While welding the piece, care should be taken not to touch the metal with the electrode. Contact will produce a crater and weaken the weld point. When the arc is struck, the welder moves the stick in a circular motion as it is fed forward in order to produce the weld. You may need to practice on several scrap or discarded pieces in order to develop a technique for properly applying the weld.

Shutdown and Clean Up Procedures

Upon completion of the welding process, the MIG welder should be shut down immediately. Hands and other exposed skin areas should be kept away from the welder during the shutdown process and the machine should be allowed to come to a complete shutdown before any component, such as the tungsten electrode is handled. Approved cleaning methods should be observed to remove any particulates that may have accumulated during the welding process.

Following these basics will help you complete your MIG weld and be safe throughout the welding process.

Car Projects that Require a MIG Welder

A MIG welder can be very useful for some car projects.

  • Floor panels. A MIG welder is ideal for welding on floor panels, when you need to replace or patch them. The metal is thin enough to weld easily, and the welding doesn't have to be exact, as it will eventually be covered by carpet.
  • Tube frames. For someone building an aluminum frame, a MIG welder will do the job very well. Be aware that if you're welding an alloy, then MIG welding isn't the best option because a poor welding technique can damage the metal.
  • Exhaust repair. If you need to perform a weld on the exhaust, you can easily use a MIG welder for this, as long as you take the proper precautions. It's easy to put a patch on an exhaust box, for example, or to install a new exhaust system with a MIG welder. The weld will be strong enough to hold well as long as the system is well supported.
  • Bodywork. Welds on the bodywork can be done with a MIG welder, although it needs to be carefully performed in order to look good once it's rubbed down and finished. In this instance, it's best to leave this project until you have experience with a MIG welder.

Where to Buy Gas and Supplies for a MIG Welder

MIG welder gas is usually an Argon blend, since Argon is both non-conductive and non-flammable. There are a number of ways to purchase MIG welder gas and other supplies for your MIG welder.

Local Stores

One of the largest national retailers of MIG welder supplies is a company called Airgas. Call 866-924-7427 or go to their website to find a store near you. Airgas has supplies for all types of welding, from welding goggles and masks, auto-darkening goggles and masks to gauntlet gloves and aprons. Airgas has over 700 locations nationwide, so there's sure to be one near you.

Online Welding Supply Houses

There are literally dozens of local and national distributors of MIG welding supplies. Three are listed below:

  • Cyberweld. Cyberweld is a one stop online shop for everything welding.
  • Welding Supply Co. This is another everything you need in one place website.
  • Ram Welding Supplies. Ram has been in business since 1949, so you know you can trust them.
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