Filler metals and electrodes

Filler metal is chosen to match the base metal. ER70S-6, also known as SG2, suits structural steel. For stainless steel choose 308L, and when joining stainless to mild steel the right choice is 309L – it tolerates the mixing of alloys in the joint. For acid-resistant stainless steel, 316L is used.

For aluminium there are two main options: 4043 melts at a lower temperature and gives a smoother weld, while 5356 is stronger and suits structures where the joint is under load.

Choose the TIG rod diameter according to sheet thickness: 1.6 mm for thin sheet and 2.4 mm for thicker. As a rule of thumb, the rod should be no thicker than the material being welded.

Store rods in a dry place. Moisture causes porosity, especially in aluminium.