Hi all I have been self teaching with welding for about 5 years now. Most of the stuff I do is 1.5mm - 4mm box and plate. I build theatre sets mainly. Got a first job with some proper thickness - need to put some 12mm plates onto the end of 100x100x 8mm box section post. It ends up as an upright column under compression as part of the structure of a theatre set. (Welds in compression thankfully but I'd still rather get it right) My setup is, Parweld Xte 201 0.8mm wire Argoshield Universal I got a little 6" offcut of the box and some of the 12mm plate and had a test weld. It wasn't amazing - I tried in one pass, I never usually turn the welder up that much, and the wire speed just made a massive buildup without a huge amount of penetration. My question is, what can I do to get the best penetration possible, it looks like I should bevel the edge of the box section, maybe pre-heat, and should I be doing multiple passes? Should I worry about penetration through the 12mm or is through the 8mm enough?