Place the fencing screen on the gate and clamp it to the metal frame of the gate. Cut the fencing to the size and shape you need with tin snips and wire cutters. Adjust the clamps to hold the screen securely to the gate. Mark the location of your welds on the gate.
Clean the gate and the fencing where it will be welded using metal files and metal sandpaper. Paint the location with flux using the brush tool in the flux can.
Light your torch set with your helmet on and down, and adjust the mixture to produce the size and heat of flame that you need. Often the gate and the screen will be of lower quality metals which will make them vulnerable to holes from too high of heat.
Apply the torch to both the fence and metal screening to heat both equally and fast. Use metal filler or solder where the metals touch to create a secure weld. Move the torch away from the metal once the weld flows. Keep in mind that many pipe-style gates will not vent the heat well and they will remain hot. Move to the other side of the gate to allow your first side to cool. Weld near the top first and then remove your clamps. You can position your clamps closer to a weld if the fencing doesn't touch the gate on its own.