Picking and Sizing your electrodes.


How to choose the right material for your resistance welding applcation and how to size properly size your electrodes.

This page was designed to help you pick the right* resistance welding electrode. 


  • Below we will review electrode materials to help determine which is right for your application and how to choose.

  • We will discuss how to pick the right electrode tip profile and size for your project.

  • And we will help you pick the right size taper (4RW, 5RW, 6RW, 7RW) for your application based on expected force. 

It is important to note, not all welding electrodes and metals are created equal. All of our proudcts are pressed and machined from virgin bar stock.

 Electrode Material

There are over a dozen copper alloys used in modern day resistance welding. Many of these alloys are speicaly metals engineered to help weld dificult welding applications.

 The most commenly used resistance welding metals are RWMA Class 2 and 3. Below is a breif summery of each alloy and their uses. More detail and addtional alloys can be found in our bar stock section.

RWMA Class 1 (C15000 & C16200)

Also know as ZIRCONIUM-COPPER. This alloy is suited for high tempature applications such as welding aluminum & magnesium alloys. The Zirconium minimizes eletrode sticking when resistance welding coated materials. C15000 can be harder to find in larger sizes.

Material substitutes: C15000 Copper Zirconium and C18150 Copper Chromium Zirconium both are good replacements for C16200 Copper Cadmium. C15000  is a good subsitute because of its excellent thermal & electrical conductivity while still offering a moderate amount of strength. The C15000 hardness properties have been developed through cold working ( similar to C16200) but the C18150 hardness properties through heat treating, which can be an advantage for larger parts.

RWMA Class 2 (C18200 & C18150)

Also know as CHROMIUM-COPPER or ZIRCONIUM-CHROMIUM-COPPER.  This alloy is suited to welding cold- and hot-rolled steels, stainless steel, and low conductivity brasses and bronzes.

Class 2: is recommended for high-production operations. It's used for welding electrodes, projection welding dies, seam welding shafts and bearings, flash and butt welding dies, and current-carrying structural components. It is heat treatable.

NOTE :  ZIRCONIUM-CHROMIUM-COPPER  should be used when welding galvanized steel & other metallic-coated steel. This is a specially heat-treated alloy, which meets the minimum electrical conductivity and hardness specifications of Class 2 alloy.

This alloy over time has been know as: CMW 3, CMW 328, Mallory 3, Tuffaloy 77, and Tuffaloy Z, CuCr, CuCrZr, C18200, and C18150.

RWMA Class 3 (C18000 & C17510)

NICKEL-COPPER (BERYLLIUM FREE)and  BERYLLIUM-NICKEL-COPPER are suited to welding steels having high electrical resistance, such as stainless steel.

Class 3: alloy is recommended for projection welding dies, resistance welding wheels, and flash and butt-welding dies. With its higher strength it is also used on high current-carrying parts such as electrode shanks and heavy-duty electrode holders. Class 3 It is heat treatable. 

Also Known as: CMW 100, CMW 353, Mallory 100, Tuffaloy 55, Tuffaloy 55A, CuNiSiCr, Weldaloy 60, and CuNiBe.

RWMA Class 20

COPPER-ALUMINUM OXIDE (Glidcop) has exceptional resistance to deformation when welding and it is highly recommended for weld caps when welding coated and galvanized steels. It allows a stable start-up and generally outlasts other cap material when welding parameters are not carefully controlled. 

Also Known as: Elkaloy 20 and CuAL₂O₃

 Don't see the alloy you're looking for? Please check out our copper alloys section



What is Elkonite?

Elkonite is a copper-tungseten alloy. Elkonite comes in up to 12 different alloys and many shapes and sizes. Copper and tungesten are not mutially soluable. Each material (tungesten and copper ) is comprised of a distinct metal which is then dispersed in to the matrix of the other through infultration. Copper tungsten bars (elkonite) is made when the tungsten powder W is pressed into the desired shape, sintered, and then infiltrated with molten copper.   

When should I use Elkonite or copper tungsten as my electrode?

As mentioned above Elkonite comes in several different alloys. Choosing the right alloy for your application is important.

Each alloy has different mechanical properties that can perform differently based on individual applications.

For example: Class 11 also known as 10w3 has a 75W/25Cu composition by weight percentage. The Class 11 material designation comes from the Resistance Welding Manufacturers Alliance (RWMA). The 10w3 alloy of Tungsten/Copper is used in resistance welding because of the good electrical conductivity and it’s excellent strength at high pressures and temperatures. Because of the added benefit of high strength and wear resistance, Class 11 is often used as a backup electrode for projection welding and stud welding.


Is it "better" to use Elkonite than copper?

 Elkonite and 

Standard RWMA tapers and force ranges

RWMA Male Shank Taper  Force Range  Taper size

The standard RWMA 4RW taper is designed for weld forces ranging from

200 - 800 LBS of force.


The standard RWMA 5RW taper is designed for weld forces ranging from

800 -1500 LBS of force.


 This page is still in progess, call 937-253-3300 for additional details or check back later.