There exists no free and universal guideline for choosing TIG welding cups. Different cup sizes are typically used for different types of metals, thicknesses, and applications.
For TIG welding, common choices include #4 (1/4″), #5 (5/16″), #6 (3/8″), #7 (1/16″) and #8 (1/2″). To choose the best cup size for a particular welding project there are few tips, we are going to share with you.
What is TIG cup size?
TIG cup size is a term that is used to describe the diameter of a TIG welding gas cup. Gas cups come in a wide variety of sizes ranging from 1/4″ to 1/2″.
Size is important as it determines the amount of shielding gas coverage you will have around the weld area.
Why use a different TIG cup size?
Different sized cups have their pros and cons. The larger the cup, the more gas is available and the harder it is to move around. The smaller the cup, the more mobile it will be and easier it to maneuver in tight spaces.
Which TIG welding cup should I choose?
There are a few things you need to consider when choosing a TIG welding cup size:
- What type of material are you welding?
- What is the thickness of the material?
- How big is the weld area?
- Can you get close to the weld joint?
What type of material are you welding?
Different materials will require a different size TIG cup. Titanium and in most cases stainless steel alloys need a larger cup due to the oxygen reacting with the base metal and creating a slag that floats on top of the molten puddle.
Carbon Steel on the other hand won’t be harmed by little oxidation so you can use the small gas cup during TIG welding.
What is the thickness of the material?
Thicker materials will require a larger TIG cup size to allow more gas into the weld joint. Thinner materials can be TIG welded with smaller cup sizes to get into tighter spaces.
How big is the weld area?
The size of the weld area will determine how big of a cup you need. A large weld area will require a larger cup size as more gas will be required to fill the puddle. A small weld area can use a smaller TIG cup size as less gas is needed to weld the joint.
Can you get close to the weld joint?
If you are unable to get close to the weld joint, you will need a small TIG cup size to get inside of tight spaces and around the corners. If you can get close to the weld joint, a large TIG cup size will be required to get the proper shielding gas coverage.
Air-Cooled vs. Water-Cooled TIG Welding Torches
An air-cooled torch is great if you don’t have water available to cool the torch. In addition, they cost a lot less. The drawback of using them is bead length. They can not perform long enough before overheating.
When control or power is important and needed, use a water-cooled TIG welding torch instead. You will be able to weld larger bead lengths and thicker materials.
Water-cooled torches use a water jacket around the torch body that is connected to a water supply. The water jacket helps to cool the torch and prevents the TIG welding rod from sticking to the tungsten electrode. This is caused by the arc being hotter than normal. It protects the tungsten electrode from getting burned or broken off.
Water-cooled torches are more expensive than air-cooled torches, but the benefits make it worth the extra money.
Which type of TIG welding torch should I choose?
If you are using the TIG welder for your hobby or to build a custom chopper, you may want to consider using an air-cooled torch. If the TIG welder is for commercial use and welding thicker metals such as steel plates then a water-cooled torch should be considered.
The tungsten should stick out about 1/4 to 3/8″ past the welding cup. You do not want to let it stick out too much, but you also don’t want it touching the weld. This will help to direct the welding gases into the weld joint and provide good shielding coverage.
The cup should be as close as possible to the weld area. As a general rule of thumb, you should try to stay within 2″ of the weld area. The closer the cup is to the weld, the better it will shield the weld pool from the atmosphere.
TIG cups are normally pink because they are made from a type of ceramic. The pink color is used to help identify the cups when they are in use. Some cup manufacturers also paint the inside of the cup with fluorescent paint to help make it easier to see in low light conditions.