Welding plays an important role in many metal fabrication projects, as it’s what fuses two pieces of metal. It’s a complex process that requires considerable skill, and things can go wrong if everything does not go as planned. There are several types of welding techniques, including MIG, TIG, stick, and oxy. Below are some of the key signs of a bad weld for each of these popular techniques.

How to Spot a Bad Weld

1. MIG

Metal inert gas (MIG) welding—the most common type—is a metal fabrication technique that makes an electrical arc between a filler wire and the weld material, which creates enough heat to turn the metal molten. Signs of a bad weld include the following: the weld line is not uniform or is too thin; cracks appear along the bead, or the parent metal is not properly discolored as it should be after heat exposure.

2. TIG

Tungsten inert gas (TIG) welding is similar to MIG except it uses a tungsten electrode instead of consumable filler wire. It's used when the look of the finished product is highly prioritized and is performed only by experienced metal fabrication technicians. It. Signs of a bad weld include porosity, lack of filler material, and a bead that's too wide without a distinct pattern. Other indications include excessive melt-through and undercutting, or grooves melted into the base metal by heat but left unfilled by filler material.

3. Stick Welding

Stick welding is a manual technique that uses an arc between the weld material and a flux-covered, consumable electrode. You can spot problems with the weld by the presence of spatter, cracking, and undercutting.

4. Oxy Welding

Oxy welding uses no arc but rather a hot flame created by a mixture of oxygen and acetylene gas. Look out for points where the metal hasn't fused completely, and for overlapping, undercutting, porosity, cracking, and spatter or metal globules.

To discuss your welding and metal fabrication needs with an experienced professional, contact C & C Machine in La Crosse, WI. They’re a full-service machine shop that can handle almost any project, whether you need portable welding service or milling and CNC machine work. Visit their website to connect with them on the web or call (608) 784-4427 to request a quote.