On your pics 3 posts ago, those show the mounting flange where the fender proper is lapped over it and spot welded together. Welding those corner cracks isn't an issue as long as you get good penetration. If your welds are hollow, you need to turn up the wire feed a touch. The ones that stand tall, especially if there's a sharp definition to the base metal means that you need more heat. It's a balancing act. If you're concerned about burn thru, you could use a backer made of copper (a piece of old copper pipe flattened and shaped to match the fender works well.) If you use a backer, you need to turn the heat a bit higher, as the backer will soak up some of the heat.
Last edited by klhansen; 10/15/2021 6:33 PM. Reason: post inserted in between
