Spoolgun question.

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Starting to play around with the 30A spool gun that came with my MM250x today. I am welding some 3/16" plate on edge to some sch 80 - 1 1/2" for a boat davit and ran into a snafu.  I had the spray transfer dialed in pretty well but when I reached the end of my weld I lingered just a touch too long and burned the edge of the plate just a bit. Usually with steel I just bump it a little to fill in the notch but with the aluminum it never seemed to fill but rather just continued to melt out. I waited for a minute to cool a bit and tried again but it still wouldn't build up. What is the trick to fill these gaps? Do I need to wait longer for it to cool down? Do I need to drop the volts to go back to short circuit transfer rather than spray?
Reply:I am making davits here in SoCal using a spool gun for my little multimatic 200.  The problem with my set up is that I start cold and end hot.  I have found that I can not stop during my weld, no matter what it does.I pre-heat before I start with a propane torch to minimize the cold start.  Sometimes when I weld the 3/16" plate to my 1.5"X3/16" tubing i use extra length and then just cut off the piece with the "cold looking" bead.To reduce the melt away, I use something to dissipate the heat that builds up.  Inside aluminum tubing you could try clamping in a steel rod to back the tube or clamp a piece of flat stock onto the opposite side of the 3/16" plate you are welding.
Reply:Hello AKmud, a couple of options might work for you. 1, start at the edge and weld to the center and then start at the other edge and meet in the middle. This assists with the build-up of heat that is causing the end to blow-out on you. Another possibility, use run-on and run-off tabs, this can help to avoid the cold start at the beginning of the weld and assist with the excessive heat at the end of your weld bead. Just a couple of thoughts for your consideration. Good luck and best regards, Allanaevald
Reply:Another vote for run-on and run-off tabs.  Just vise grip them in place and snap off when done.Solves the cold start, hot finish problem.Dave J.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Thanks guys, I'll give it a try. (After I get some new contact tips.... )
Reply:(After I get some new contact tips.... )