I have tried both the flush tip and the recessed tip with my mig. I believe the flush is called direct transfer and recessed tip is spray transfer. On light guage, 18-20 guage, steel sheet metal which one seems to give the best results? Same for heavy guage steel, > 1/8". I seem to get good results on light guage with recessed tips and good on heavy with flush tips. What is the reason for one or the other or is it just preference. Is one better than the other for overhead welding?
I don't know about "direct transfer" but most of the MIG welding we do on our hot rods is not spray transfer. If you're using 75/25 Argon/CO2 mix it is fairly hard to get to spray transfer. 75/25 is too much C02. Spray sounds like 'whooosh'. Spray transfer is certainly possible with a different gas like 90/10 but most spray transfer welding has to be flat or horizontal. Overhead is hard enough as it is and I think it's pretty impossible with solid wire spray transfer. The MIG process we use is called short-circuit transfer. Sounds like sizzling bacon frying. Where you set the contact tip in relationship to the gas nozzle is a matter of personal preference but I usually keep mine sticking past the nozzle just a little. Recessing the tip inside the nozzle means your ESO (length of wire from the tip to the weld pool) is usually too long for short circuit. Take a long look at www.weldingtipsandtricks.com
Spray transfer...(been a long time since welding school)Is only after you are above I think 24+ volts, a bit higher if I remember from my mig welding days.Way to hot for any thing you weld on a hotrod even a frame.Lots of heat and wire almost sounds like whistleing,looks like you are squirting metal on!
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