I'm building a sports car chassis out of RHS and tubes in mild steel. I am a relatively new welder and using a Millermatic 140 (MIG) for the project.

I've gotten to the point where I need to weld some 0.75" x 16 gauge tubular cross braces into a larger structure of 1.5" x 1.0" 14 gauge RHS (photo below).


While this is my first real need to do this, I will be doing it many times over the project and I'd like to produce high quality welds I'll be proud of. I'm not worried about them being strong enough. I've got the penetration, etc. down and my practice welds are plenty strong. However, I'd like some help on getting the weld to look good and flow together. Intuitively, my approach is to do 4 welds where each one is 1/4 of the perimeter of the joint. I don't know if that's right or wrong. It's just what came to mind.

Also, the 4 segments don't overlap well and you can see each of the 4 welds clearly (examples below). I've seen much better on professional race cars, so I'm looking for some help and suggestions on how to make mine look good while remaining strong.

Also, while my samples below are at 90 and 15 degrees, there are quite a few that will be at 45 degrees too. How does one handle the narrow (tight) part of those 45 degree welds? Do you let the filler wire get long and close to the join or do you just try to build up a fillet and don't worry about getting in deep between the pieces?