Why not weld on concrete?

Welding on concrete is not advisable because the high temperatures involved can cause thermal shock, leading to cracking and damage to the concrete. Additionally, the sparks and molten metal produced during welding can create fire hazards and damage the surface. It's also challenging to maintain a stable and level work surface on concrete, which can compromise the quality of the weld. Instead, it's better to use metal surfaces or designated welding tables.