For the autobody repairs that I'm doing, I'm using a lot of plug welds. Obviously, these don't have the same appearance as the factory spot welds. I recently picked up a used miller spot welder and was wondering if I could go back and use the spot welder over the plug weld. I've tested it on pieces and it looks OK and seems strong enough. Intuitively, it seems like it should be OK. I'm just an amateur, so I thought I would get opinions from people with more experience. My real concern is does it weaken the original plug weld? Is there any downside to doing this? Any other thoughts?