Why use Skip Welds in Welding and Fabrication?
Skip welds or what some people call intermittent welds are a good tool to use in the right situation. Use of skip welds can reduce distortion, speed up production, reduce costs and reduce weight. Sometimes every lineal inch of joint need not be welded. Certain components or weld joints require 100 percent welding. When that is not the case, we might consider the use of skip welds. Skip welds are welds that are not completely welded the entire length. A segment of the joint is welded followed by a segment not welded. This alternating of welded and not welded segments continues along the joint as needed.
Skip welds are defined by a specific length of weld, and a pitch dimension. The pitch is defined as the center to center distance between the welded segments. Too often the pitch is mistakenly thought to be the length of the unwelded segment as opposed to the center to center distance between welds.
If we have to produce a full penetration weld in a butt joint, skip welds are not an option. If we have to produce a pipe weld that has to retain air or gas pressure, skip welds are not an option. If we have to produce a weld that has to contain or seal a liquid type joint, skip welds are not an option. These are but a few examples of when we cannot use skip welds.
A flat bar attached to a cat walk as a toe board is a good use for skip welds. A stiffener attached to the back of a large flat surface is a good use for skip welds. Any tee or lap joint fillet weld that does not require full strength is also a good choice for skip welds.
Skip welds reduce distortion by reducing the amount of overall weld required, thus reducing the amount of heat input. Reducing the amount welding also reduces the shrinkage that occurs from welding.
Production speeds can increase because not all of the joint is required to be welded. If the amount of welding is reduced to as much as half there is a chance to double production speeds.
The weight of a part can be reduced if the amount of weld applied is reduced. Skip welds are a great tool to reduce the amount weld required, and in the process reducing weight of the part. A specific welding pattern called staggered skip welds is a good way to maintain strength and reduce weight. In staggered skip welds, the weld on the near side of the joint is welded opposite an unwelded section on the opposite side of the joint.
Finally, reducing the amount of weld by using skips can reduce costs. Cost savings are seen in reduced, weld filler metal, electrical power, shielding gas and labor just to name a few. On the other hand, there are increased costs associated with skip welds in the area of labor too. Layout of the skip welds prior to welding adds to the labor and time required to prep the joint for welding. Cost savings, reduced distortion, reduced weight and increased production speeds can be had if skip welds are used in the correct application.
Check out the Longevity website (www.longevity-inc.com) or YouTube channel (www.youtube.com/longevitywelding) for more details and information about equipment for different welding and cutting processes. Longevity has the right machine for your exact application, so take a look and choose what is the best fit for your materials, product and needs.