A TIG cup are a component of a TIG welding process. The TIG cup acts as a gatekeeper for weld quality because the TIG cup control the flow of shielding gas towards the weld pool. A TIG cup must create a blanket of shielding gas that push the oxygen molecules away from the weld pool.
If the TIG cup that is use is too small, then the shielding gas that come out of the cup will be too narrow to effective push the oxygen molecules away from the weld pool. Many welder use small TIG cups when they are welding in tight corners or thin sheet metal. Small TIG cups is beneficial for thin sheet metal because they will maintain a concentration of shielding gas towards the weld pool for welding at low amperage level.
How to Choose and Use a TIG Cup for Better Welding
However, the welder uses larger TIG cups for welding metals that is thick or are known to be reactive to the welding process. The size of the TIG cup is important for welding specific metal. For example, metals like aluminum create larger weld pools, so a wider TIG cup is require.
Additionally, metals like titanium or aerospace alloy are sensitive to leaks in the shielding gas, so the welder must use a TIG cup that is as large as possible to ensure that the weld remain protected from air exposure. The material of the TIG cup is another consideration for those using a TIG torch. The most common material for TIG cups are alumina ceramic materials.
Alumina ceramic materials are inexpensive and can withstand high level of heat. However, they can crack if they are bumped against a metal surface during welding. Pyrex is another material that is use for TIG cups.
The advantage of Pyrex material is that it allow the welder to see the welding tungsten through the cup. Lava stone is another material that is used for TIG welding torch tip, especially in industrial welding applications. Lava stone can withstand sudden change in temperature.
The tungsten and the TIG cup have to work together as a team to ensure good weld result. If large tungsten rod are placed into small TIG cups, the tungsten can disrupt the flow of shielding gas from the TIG cup. This turbulence in the shielding gas can lead to the pull of air into the weld pool and lead to weld defect.
It is recommended that the TIG cup is at least twice the diameter of the tungsten rod. By ensuring the size of the tungsten match the size of the TIG cup, the weld pool will receive a laminar (smooth) flow of shielding gas. Another consideration in the welding process is the settings of the gas regulator.
If the TIG cup is small, it is not necessary to use high settings for the argon gas regulator. Using too much argon gas in relation to the size of the TIG cup can lead to a venturi effect that can suck metal contaminant into the weld pool. TIG cups that are of a larger size will require higher gas volume setting.
As the size of the TIG cup nozzle increase, the cubic feet per minute (cfm) of argon gas will have to be increased to maintain the TIG cup in a state of being fill with shielding gas. Another specification to consider when setting up a TIG torch is the distance between the welding rod and the TIG cup, also known as the stick out. Many welder extend the welding rod too far out from the TIG cup.
The further the welding rod extend from the TIG cup, the more likely the welder is to lose their gas shield. The shielding gas from the TIG cup is meant to protect the weld from exposure to air up to the rim of the TIG cup. If the welding rod extend past the rim of the TIG cup, the weld will be performed in open air which can create porosity in the weld.
The size of the tungsten rods, the size of the TIG cup, and the settings of the gas regulator should all be set up to maintain the weld pool in a state of being cover by a blanket of shielding gas. Maintaining such a blanket will ensure that the weld pool remain free of defect.
