I'm building a set of 304SS headers and I'm using a Diversion 165. I've been practicing quite a bit, but my question is if I only use enough filler rod to keep my puddle going, is the weld going to be strong enough??? I dab a little push the weld a ways and then dab a little more... I can make the weld look very pretty with this method, but I want it to be strong as well...

Another question, if the butt weld joints are perfect with absolutely no gaps, is filler rod even required????

Thanks in advance!!!!