TACK WELDING
Have you ever wondered what the difference is between ‘tack welding’ versus ‘fully welded’ when buying restaurant equipment or food service equipment? While not the most exciting subject, knowing the difference and buying the product that is welded in the way that will best meet your needs can save you money in the long run. Tack welding can be sufficient for light duty items and equipment. Fully welded is the term used for a complete weld on an object which provides the user the strongest weld possible when done correctly.

The following paragraphs are excerpts from an article by Elia E. Levi; a retired welding consultant and a Mechanical Engineer ( E. Levi is not affiliated with Cook’s Direct, Inc.):

‘Tack welding, a necessary preliminary step in many welding projects, must be performed correctly to achieve optimal results from the final weld and to minimize part defects. Quality is as important in tack welding as it is in the final weld.’ This article describes proper tack welding conditions.

WHAT IS TACK WELDING?
After items to be welded together have been positioned as required, generally by clamping them on suitable fixtures, tack welds are typically used as a temporary means to hold the components in the proper location, alignment, and distance apart, until final welding can be completed. However, light duty kitchen and other equipment items use tack welds as the final weld. Equipment that is tack welded does not have the strength and integrity you would find in a fully welded piece.
In short-production-run manual welding operations, tack welding can be used to set up the work pieces without using fixtures. Typically, tack welds are short welds. In any construction, several tack welds are made at some distance from each other to hold edges together.

DEFECTIVE TACK WELD RISKS
When hoisted, moved or stressed in any way - improperly tack welded assemblies can rupture, and portions or subassemblies may disassemble, fail and endanger people or damage property.
The brittle metal can crack during solidification of the weld metal or when stressed. Under bead cracks cannot be readily detected by visual inspection, and more thorough nondestructive tests may not be performed if they are deemed unimportant for such limited welds. However, these small cracks can cause the whole structure to fail. Fully welded items are always stronger. When purchasing food service equipment for heavy duty applications, fully welded items may be more expensive but will have an increased life span and should prove to be a greater value.

Submitted by: Howard Breeden

Howard Breeden, was the founder of Szabo/Aramark Correctional Services, the Breeden Group and is the founder of Cook’s Correctional Equipment- now Cook’s Direct, and has developed, invented and patented stainless steel items for food service operations.

Elia E. Levi is a welding consultant. E. Levi can be reached at www.welding-advisers.com