Welding is an industrial process that involves more variables and sciences than many others, with a variety of welding methods being used for different applications. Choosing the most appropriate alternative will enhance the durability of the weld, producing a finish free from defects.

Although tests are in place to assess its integrity, there are a number of visual indicators that can signify a bad weld. The following key points will allow anyone to identify if any specific job remit has been fulfilled to a credible and safe standard.

MIG welding

The signs of a bad weld can include:

• A lack of uniformity
• Too thin – the parent metal should be about one-eighth of an inch
• Cracks down the middle of the bead
• A lack of discolouration of the parent metal

TIG welding

The signs of a bad weld can include:

• Insufficient penetration to the underside of the weld
• Excessive globules of metal
• Undersized or oversized welds
• Incomplete fusion
• Porosity or cracking
• Undercut or overlap

Arc welding

The signs of a bad weld can include:

• Excessive spatter
• Undercutting
• Cracking
• A visible lack of fusion

Oxy welding

Signs of a bad weld include:

• Insufficient penetration to the underside
• Excessive globules of metal
• Undersized or oversized welds
• Undercut or overlapping
• Incomplete fusion
• Porosity and cracking

Most defective welding is due to an incorrect welding procedure and once the cause is determined, the operator can correct the problem.

What if your weld is below standard?

If you feel the weld you have been given is not up to standard or if you think it might be a safety risk, it is important that you advise the operator that it must be re-done. If the welds are very poor, you have no choice but to grind them out, as piling more filler on top of an already bad weld is not a safe solution – it might cause a weakening of the area adjacent to the weld. If the job isn’t done properly your new weld will fail.

Established in 1980, Pipecraft specialises in high-quality metal fabrication processes. To ensure that your projects are completed on spec, on time and on budget, we use only the best design technology and materials to guarantee consistent quality. To discuss your project with the professionals, please call Pipecraft on 01903 766778.