Heat Content of the Weld Pool

The weld pool must get hot enough that base and filler material melt cleanly and mix. If you put too much heat in, the pool runs away and you get undercuts or porosity. If there's too little heat, the base material doesn't melt properly, the weld doesn't bond, and it cracks later. Set the machine so the pool flows calm and even, without boiling or spattering. You can recognize the right setting by the shape of the weld and the pool – you have to keep an eye on that. If the pool gets too fluid, turn down the power; if it doesn't wet properly, you need to give more energy.