Hello all, I have the opportunity to learn how to weld on my friends millermatic 251. He has it set up for mig spool and uses 0.035 ER4043 as the filler. I have done very limited mig (steel) welding back in the day during highschool. I am trying to weld 1/8 square tubing which I will eventually be welding into a bedframe. After doing some test pieces I realized I was getting very little if any penetration on my welds. I used the chart on the welder to set my parameters (19v, 400 wire speed) and I used a new grinder flat disk to clean the pieces.

I tried a couple different methods such as uping the voltage (As I thought this correlated with bead depth) and messing around with the wire speed. I also tried preheating the metal with a torch. Nothing seemed to make much of a difference. From watching several videos and reading some articles I have learned that the bead depth is actually related to amperage which in turn is dictated by wire speed. Although I messed around with wire speed a bit I for the most part was focused on voltage. Tomorrow I will have access to the machine again and I plan to keep the voltage constant while adjusting wire speed to see if I can increase penetration.

Here is a picture of one of my horrible attempts:
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Does this appear to be a wire speed issue to you guys? Any additional tips for a new welder? Also I'm assuming in order to test my beads I should be able to bend the square tubing without the weld breaking is that correct? Currently I can break them with a few taps of the hammer which I am sure is too weak...