Ending an aluminum pass

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I have been welding aluminum now for about a month, I use a Millermatic 252 with a Miller spoolmatic 30A, straight argon, approx 25 cfh, filler AL 5356. I get pretty good results on my weld until I get to the end, I always seem to leave a crater there, I have tried moving back to fill it but can never get a nice result, any suggestion would be appreciated. I will post photo's of results.Guy_48Welding is an art......Millermatic 252Lincoln SP175PlusLincoln 225 AC/DC
Reply:Stop moving, build a little tit, lower the heat and move the torch backwards as you back off.It works for meDavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:David,He's using a 30A Spoolgun on an MM252, not a tig torch.  How do you suggest he "back off on the heat"?Guy,What I've found is that, at the end of the bead, you just need to pause (stop moving forward) with the gun and let the wire fill the void.  Just takes a little practice, since we get used to running so fast with aluminum.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:It's easy, when you get to the end of the weld were you would normally stop back step the gun about 3/4 of an inch and let the weld end about 3/4 of an inch before the end of the plate. It's hard to explain but the lincoln book has a good pic of it on 9.3-8. Figure 9-10 --Gol'
Reply:thanks fellows, appreciate it, I have tried back stepping and filling like mild steel but was not successful. I will try and stop, back step a bit and stay still for a second, see what happens.Guy_48Welding is an art......Millermatic 252Lincoln SP175PlusLincoln 225 AC/DC
Reply:Oops....  I stop at the end of the bead and count to 3 then let go of the trigger.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David ROops....  I stop at the end of the bead and count to 3 then let go of the trigger.David
Reply:David,If you're counting to three, with aluminum, you surely won't have a crater.What you'll have is a clump of aluminum about the size of a quarter.Guy,You'll have to find your own time, but it won't take three seconds.  You may even make a small circle with the gun about the diameter of the regular bead.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:also turn you gas up to 75-80...and yes you wont need 3 seconds but youll see it fill up6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:ok, days off coming up, I'll give it a shot and post some photo's of my progress, thanks again to all who have responded.Guy_48Welding is an art......Millermatic 252Lincoln SP175PlusLincoln 225 AC/DC
Reply:Originally Posted by welder155also turn you gas up to 75-80...and yes you wont need 3 seconds but youll see it fill up
Reply:not according to the cwi at work. 6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:35 cfh is about right for me.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David R35 cfh is about right for me.David
Reply:Welder155, your CWI should be careful with his recommendations without knowing material thickness, wire diameter and travel speed.  I'm not saying anyone is right or wrong, I just don't like seeing the title thrown around haphazardly.
Reply:The OP is using a MM252 with 30A Spoolgun.  He sure as He11 DOESN'T need 75-80 CFH gas flow.  Bad advice.  Does your CWI work full time for a gas supplier?Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:One thing I have found is that if your material is not thick enough to pause without burning through is to end the pass, pausing for a few seconds and then leaving another "tack" on top of the crater and dimple to kinda fill it in. Not the best looking fix, but it looks better than a void. Sometimes its all you can do to keep from burning through.
Reply:ok guys sorry. apparently im stupid. relax im only 17 and i NEVER said i was the only right one. 1. we use the spool gun on 3/8 and bigger everythign else is tig, so he says run 75-85 to help prevent porosity.2. no he doesnt work for a gas supplier,  he shouldnt have to work for a gas supplier since hes an inspector. dont know why you would say that?are you using spray transfer?and ps dont call any advice bad advice because like everything else it takes practice and the trial and error.6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:also since it doesnt state material thickness dont just jump to conclusionsaluminum soaks up heat so dont bother doing aluminum wire under 1/4"6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:i've been welding aluminum for about 3 and a half years now and i'd say put your gas at 35.. the regulators we use at work only go up to about 50 anyways. We also use a miller 252 and 30A spoolgun but our base material is 6061 and our filler is 4043 cause we find that it gives us the best results but what i've found for as the best way for filling in a crater is to just do your weld normally then wait a couple seconds for it to solidify then fill the end then backstep 1/4" to 1/2".. or you could always just use a runoff tab and cut it off when you're donehttp://specific.net
Reply:Originally Posted by welder155also since it doesnt state material thickness dont just jump to conclusionsaluminum soaks up heat so dont bother doing aluminum wire under 1/4"
Reply:Originally Posted by Hammack_Welding  if it is setup right,then you should not be limited to 1/4" and above material with wire.