How can you prevent "blowholes" in a MIG weld?

Preventing "blowholes" in a MIG weld is primarily about ensuring that the welding process has the right conditions for a clean and effective bond. Maintaining proper gas coverage is essential because the gas shield protects the molten weld pool from atmospheric contaminants, such as moisture and oxygen, that can lead to the formation of blowholes. If the gas shield is insufficient or interrupted, environmental factors can enter the weld area, causing trapped gases to expand and create voids in the finished weld.

Additionally, cleaning the base material is crucial. Any contaminants such as rust, oil, or dirt can contribute to gas entrapment, which results in blowholes. Properly cleaned and prepared surfaces allow for a better fusion of the base materials without creating pockets for gases to accumulate.

Therefore, the combination of ensuring adequate gas coverage and cleaning the base material directly addresses the causes of blowholes, making it the most effective way to prevent them in MIG welding.