Imperfections in porosity are often cited as a common problem for TIG wielding, including when aluminum is used. While multiple steps can be taken to resolve this issue, adjusting the shielding gas flow rate and using a different filter rod can make a noticeable difference.
Undercutting is a similar problem that can occur when TIG welding aluminum. This is caused by the improper filling of a groove with the melted fill material, leading to joint weakness. To resolve this problem, recheck the angle at which you are holding the torch and ensure that you are evenly distributing fill material as you work.