I have more experience in making welds that look like that work. Even when working as a continuos bead on a mig (flux or solid core) half the time, you are heating the filler up to lay on top of the already layed material as you go.(This makes no sense to a weldor at all,burning in one consistant pass gives continuos heat and penetration in the area,tacking and move method does NOT,it lets the area cool and heat,which actualy creates stress within the weldmant and gets very little penetration) Basically with the tack option, you are putting the most heat to that exact point as you go...(burning one consistant pass with no stop n go will get you MORE penetration,not an opinion,a FACT), and not just laying more material on top of rod. With the tacking option also, you are fusing the materials together, not just laying material on top of it.
none of this makes any sense to me and other true weldors
With heavy equipment I have the most experience welding as far as excavators/loaders and attachments such as bosses on buckets and rakes. Most of the factory welds would break after enough abuse. Usually they break along the weld line and sometimes it would creep through 1/2 to 3/4" steel. Instead of going along the lines of the weld where the two materials will meet, I would lay a tack bead along there, then go the opposite way. Criss crossing them 2 layers with the tack option. After I learned that, no welds of mine ever broke. A tool I made out of forklift forks withstood a 50 ton jack with no cracks with "tack" welding. 1 and 1/2 steel 90 deg welded together in a u-shape was the base of the jack. It bent the 90's of the 1 1/2 and the base, but did not crack.
Also whenever welding, flat is preferred, but if you have to go vertical, that tacking option works best for me. That way there is no puddle falling at all. That is all, IMO, carry on.
If you have problems welding a vertical without using a "tack n go" method,then you need more practice welding to be a weldor...
I agree totaly with jeepfreak383,that tacking method is a weaker weld,it makes for a weaker weld for the fact you are not generating enough penetration through the whole weld,this also puts stress within the weldmant itself.
If you are having problems on welds holding up on heavy equipment as you say, then you are either using the wrong filler metal and/or not using the right pre-heat and post heat method needed for that type of wear plate or hardened steel.
If that was the case,then all those welds made during the building of the heavy equipment would all have that"tack n go method" from the factory,which they do NOT..for a GOOD reason...
The Pre-heat and post heat releives the stress created by the weld on exotic metals,DH-2..T1..etc..i can't think of the long list of hardened steel used on heavy equipment at the moment,there is a long list of the different types used,but they all have to be treated different when welding,you can't just grab any filler metal/rod and "git'rdun" without failure unless you go by the right procedures and materials they are designed for...Carry on