When to Bend Tubing—And How to Do It Right

When to Bend Tubing—And How to Do It Right

Mike Gagel, Strategic Services Specialist, Swagelok Pittsburgh and Trainer, Advanced Tube Bending, Swagelok Company

Many decisions must be made during the design and assembly of a new fluid system or when replacing components in an existing one. Those decisions include choosing between stainless steel tubing or pipe and determining how those materials will be routed to deliver system media where needed.

While threaded pipe has historically been a reliable choice in fluid system applications, tubing is a beneficial alternative for a variety of reasons. One of those reasons is tubing’s easy bendability and routing capabilities, which can help operators achieve more intricate and efficient fluid system design with fewer connection points.

Tube bending takes skill. To do it right, you should be able to identify where tube bends are most applicable and can benefit your system. You must also be capable of making high-quality bends, following best practices and using the right equipment. Here is a primer on bent tubing, where it can be most advantageous, and what you need to know to bend tube successfully:

When to bend tubing.

Planning ahead is a necessity for proper fluid system design and assembly. No matter the materials you choose for fluid conveyance, your goal is to get liquids or gases from point A to point B without interfering with other critical parts of your system. Depending on your application, accomplishing this goal may not be simple.

First, determine whether tubing will be advantageous over pipe. There are a few considerations to be made here. To make a desired run using pipe, the pipe must be cut, deburred, and threaded. All male threads must be wrapped with a PTFE tape or covered with a sealant. The pipe fittings are then tightened with a wrench. A well-built system can provide high reliability, but the assembly process can take up significant labor time, especially for a complex system application. Additionally, each new introduced fitting connection is a potential leak point even if it has been put together by a skilled assembler.

Tubing provides some benefits here. It must also be cut and deburred, but most directional changes can be accomplished with a bend instead of a new fitting. A single bent tube can accomplish several directional changes as opposed to pipe where many different runs and fitting connections would be required. Additionally, compared to a pipe elbow, a tubing bend creates less turbulence as system media flows through it. Tubing is also lighter weight than pipe and will not require as many supplementary supports.

As you establish and plan your desired tube routes, determine how you will perform your directional changes. These will be accomplished by bends, or by connecting separate lengths of tubing with high-quality tube fittings. Bends are applicable for many directional changes—but your choice between a bend or a fitting largely depends on the situation.

Simple 90-degree directional changes (as shown here), which are useful for any necessary offsets in your line, can often be most effectively accomplished with bends. For example, if a tubing run needs to traverse a panel without preventing easy access (shown here), a series of 90-degree bends can be effective. Bending is also beneficial in confined areas where several lengths of tube must change direction in proximity to each other. More complex methods, like rolling offset, parallel, complex, and segmented bends can also be applied, and may require advanced bending skills and experience.

Bends are not applicable everywhere. A minimum length of tubing is required to bend yet still allow the tube to be installed in the tube fitting safely. If you are dealing with several short lengths of tubing, it is more appropriate to use fitting connections for a directional change. Additionally, if a certain required directional change will require a more complex bend than you are comfortable making, it may be beneficial to use a fitting. This situation illustrates why skill and experience are so important to creating safe, efficient, and cost-effective systems with bent tubing.

Applying the art of tube bending

Once you have decided to deploy bent tubing for your fluid system needs, it is important that you have the right skills to perform the work correctly. Tube bending is as much an art as it is a skill, requiring technicians to think in three dimensions to turn designs on paper into physical systems. And even if the first several bends made on a piece of tube are flawless, a mistake on the final bend can cause the entire length of tube to become scrap.

From a practical standpoint, operators must also know how to use a tube bender and other equipment to complete accurate, quality bends. There are two common pieces of equipment that are applicable for many bending applications: a hand tube bender and a benchtop tube bender. In the following videos, you can find practical instruction on how to use each type of tube bender:

How to use a hand tube bender:

In this video, learn how to use a hand tube bender to accurately and efficiently make 90° and 180° bends in tubing. Swagelok^® hand tube benders provide consistent, high-quality bends in tubing made from most materials used with Swagelok tube fittings.

How to use a benchtop tube bender:

In this step-by-step instructional video, learn how to use the Swagelok^® bench top tube bender to produce accurate, repeatable, high-quality bends in tubing made from most materials.

Following the best practices established in these videos can help technicians avoid a variety of common defects that can compromise the integrity of even the simplest bends, resulting in a waste of time, labor, and money.

Ultimately, creating quality tube bends—especially more advanced bends—requires skill that comes with practice and experience. Training courses can be invaluable for equipping technicians with the practical knowledge needed to create safe, efficient fluid systems with bent tubing. This is why Swagelok has developed training courses for tube bending, ranging from the essentials to more advanced techniques, to help fluid system professionals learn practical skills they can apply in their facilities. If you are interested in learning more about how we can help you enhance your tube bending abilities, contact our team today.

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