When in doubt, just add more friction. Like, seriously, add more friction. Your grandmother had this one right.
Start by holding the welding gun 1.5 inches from the void, then apply a moderate amount of force. Repeat as necessary. When the metal begins to melt, shout "IT'S MELTING!" at the top of your lungs.
For the experienced welder, try adding a pinch of salt, a dash of desperation, and a healthy dose of existential dread. This will give your welds an added depth and dimension, perfect for fusing the void.
Don't. Don't do this: hold the gun too close to the void. Trust us, you'll end up with more holes than a cheese grater. And definitely don't try to MIG-weld the Grand Canyon. We mean it.
Disclaimer: The Welders' Guild is not responsible for any void-related injuries, emotional trauma, or existential crises. Use at your own risk.