Planning to replace some inner fenders on a 1966 Mustang.   I needed to play with my welder and see if it worked again anyway, so I thought about the few different ways to do this.   I decided to weld from the outside in!   This actually simulates spot welds on the parts that show quite well.

I got some 16 gauge and 14 gauge sheet metal at the hardware store to give it a practice test.  I used to do these quite a bit at my old job, but I have not done too many rosette welds in years.   When I go to drill the spot welds out, I am just going to drill completely through them, leaving holes in the framerail.

Heres a sample.  I hit the first 4 and blew a hole in #5 for practice repairing it.   Heres what the first 3 would look like from the FRAME RAIL side. second photo   The first photo is what the inner panel will look like.  The one on the far left is the one I purposely blew a hole in to repair.     

Now, you clean your rosette welds AND The frontside.  Then you go back and hit the weld from the backside a second time with a higher heat AND low wire speed.   then clean it off a second time (easier this time)    Now this may not be for everyone, but if you want to simulate some spot welds in high showing areas, heres my idea.  I played with different heat settings to get the best spot weld simulation (far right)    This may not be for everyone,  some might not like having to grind a bit of weld off the original weld a second time.  However, It DOES make a nice circular impression!