Spot welding (also called resistance spot welding) is the process of using an electric current to permanently joini two or more metal parts that have a thickness of up to 3 mm. Spot welding provides reliable welds, as you can control the energy delivered to the spot.

The most common application of spot welding is in the automotive industry, where automobile manufacturers use spot welding to weld sheet metal in order to form automobile parts. The aerospace, construction, electronics and medical equipment industries also use spot welding.

Some important parameters you must consider before purchasing spot welding equipment are:

1. Surface finish requirements
2. Resistance of base metal and amount of current flow required for necessary heat generation
3. Thickness of total weldment
4. Diameter of the spot weld

Action Steps
The best contacts and resources to help you get it done

Buy a spot welder from reputable suppliers of spot welding equipment

Once you understand your requirements, evaluate standard spot welding equipment available in the market.

I recommend: Miyachi Unitek, a reputable manufacturer of spot welding machines, also offers spot weld controls and weld heads for large-scale spot welding applications. Polaris Electronics offers a range of spot welders with AC or DC current. Weld-Action Company is another manufacturer and supplier of automated welding equipment.

Buy standard spot welding accessories

To ensure that your spot welding equipment works efficiently, buy standard spot welding accessories from manufacturers of spot welding supplies and accessories.

I recommend: Miller Electric Mfg. provides tongs and tips of various configurations for both air-cooled and water cooled spot welding equipment. Airgas also offers supplies and equipment of a number of leading brands, including Lincoln Electric, Miller Electric, Victor, Tweco, Esab and Hypertherm. American Chowel is a good source from which to buy standard electrodes and other accessories. You can also buy spot welding tools from Weiler Welding, a distributor of welding equipment manufacturers such as Hypertherm, Lincoln Electric and Miller.

Buy used spot welding equipment

A used spot welding machine can provide you a cost effective solution for your welding requirements. However, make sure you buy a good quality product with a warranty.

I recommend: Spotwelding Consultant Inc. offers reconditioned spot welding machines from various reputable manufacturers like acme, Taylor Winfield and Unitek. You can check out used spot welders at Used-Line.com, a retailer of used industrial equipment. You can buy used spot welders from Surplus Record Machinery & Equipment Directory, an Ariba Company that sells used equipment.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Excessive tong pressure and extended weld time can result in improper spot weld.
• •  To avoid accidents, wear proper safety gear such as safety goggles and dry insulating gloves.
• •  Buy spot welders from the suppliers of spot welding equipment that also provide accessories.