Video illustration for the set up of Capacitor Discharge Stud Welding for general applications including Weld Studs. A portable, 110 volt, Stud Welder with handheld C.D. Weld Gun, is used to show the parts & components needed for proper operation and weld application with this high-speed fastening process.


  • SUMMARY of the Capacitor Discharge Process, Components, Features & Benefits
  • Equipment connections for C.D. Studwelders
  • Accessories required and Capacitor Discharge Weld Gun setup
  • Welding of C.D. Studs: Features & Benefits


Capacitor Discharge, often called “CD” welding for short, is characterized by the use of everyday power from an ordinary one-hundred-and-ten volt electrical outlet. This process is part of a larger family of fastening methods known as Stud Welding, or “Pin” Welding.

At Midwest Fasteners, we know that saving time is crucial to all types of operations. And easy to use, portable studwelding can be used to install many varieties of fasteners.

Since equipment setup is critical to getting the job done properly, let’s take a look at how Midwest Fasteners can help.

CD Welding Systems use readily-available, everyday electricity, and this is only one of the things that makes them:

  • very portable
  • made up of simple, light-weight parts,
  • able to work in short, low-temperature, weld cycles,
  • and used on sheet metal thickness material to create high strength welded fasteners in lots of types.

From this we get strength, speed and reliability by a simple process.

Capacitor Discharge studwelding occurs in 4 instant steps.

  • Contact
  • Ignition
  • Placement of the Stud (or ‘closing the Gap’)
  • and, “Bonding” of the Weld

For a closer look at setting up the C.D. stud, or pin, “welder” we’ll use a standard portable Midwest Fasteners Capacitor Discharge system.

First, the main unit is called the power unit, or “Controller”. It connects to one-hundred-and-volt or “wall power”. Some units have detachable power cords, some come with a power cord connected.

Next, the Capacitor Discharge gun is connected by Weld and Control Cables to the power unit. These hook-ups will provide signal to the unit from the gun and pass the weld charge during the actual weld cycle.

Each Capacitor Discharge stud welding system also has a Ground Cable, which is essential to “complete” the circuit for the weld cycle.

Finally, proper accessories are needed to prepare the gun for welding a specific type and size of fastener.

These components make up the “contact” capacitor discharge stud welding system as provided by all MIDWEST Fasteners CD portables.

Now, here’s a closer look at how to hook up a Capacitor Discharge stud welding unit.

Keep safety in mind in the operation of StudWelding and all types of power equipment. Always observe local and job-related safety practices, and keep in mind that this is electrical equipment capable of producing substantial power and voltages. Be sure to consult Manuals for your equipment and review trade-related guidelines for best practices under all conditions.

Connect the Ground Cable to the Unit, based on unit markings provided on the Control Unit.

Also, note here, some units have special “hook ups” for Ground connection based on the welding to be done, something like “CD” or “Cuphead”. If so, follow those markings.

You will also have a simple, single ground connection port.

Complete “grounding the work” by connecting the Ground Clamp to the metal to be welded. Make sure that this connection is tight and “clean” at all times.

Most stud welding is set up in “straight” polarity with the Ground “Positive” and the Gun providing the “Negative” pole for weld flow. Reverse polarity is also an available hook-up and can be used in some applications. Consult your References and Stud welding suppliers if you need to know more.

Next, the Gun is connected to the Power Unit by two cables:

  • a weld cable,
  • and a control line

Again, manufacturers provide markings to assist in helping to set up and connect properly. In each case, make sure the connections are sound and tight plus “locked” into place properly with their connector.

Finally make your power connection with the Power Cord.

Remember, easy hook up and portability allow you to “use” the CD system virtually anywhere, and only one-hundred-and-ten volt “everyday” electricity is needed.

Finally, select and properly install the right Accessories in, an on the CD gun. This is done based on the type and size of fasteners to be welded with the CD system. All connections here should be tight and complete; just as with the cable connections before.

With these simple steps completed, you can turn the Controller ON and your Capacitor Discharge system is ready-to-weld for stud, or pin, welding.


  • Load
  • Contact
  • Weld

With that you have fast installation, reliable results, with a high quality weld.

A weld that is strong, even under substantial loads through a bond that is formed immediately, and that will fail in the fastener BEFORE it fails in the weld under tests.

Capacitor Discharge stud welding and Midwest Fasteners’ CD portable equipment is fast, reliable, and gives superior weld strength on many types of fasteners.

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