Fire, That, the welding process used, operator skill, can & will all affect it. A continuous weld bead with a minimum of slag inclusion & good penetration ( means heat) is what most would agree gives the best strength.
We have machines available today so good that you can nearly lay a beautiful bead down on tissue paper. Due to that, we need even more skill to create a strong weld.
Practice pieces are still the best if you don't do a particular process enough to be sure of the results. Or, job it out to a pro.
Doug
