Extreme difficulty with aluminum

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Ok short story I have previously made acceptable welds on aluminum scrap using 4043 filler. I haven't tried to do any aluminum recently, got my bottle refilled and attempted to weld a bung on a cast valve cover yesterday. It went terrible I preheated it with a torch, stainless brushed it then wiped with acetone. Tried to lay a bead and it just spattered and contaminated the second I even thought about putting my filler in the puddle. After 10 failed attempts I just tried to lay a flat bead on a piece of scrap and the same thing happened. The second the filler melted it contaminated everything and made a mess.In summary do I just suck or could I have gotten argon c02 mix? I was also having trouble just keeping an arc it was like oxidizing and the arc would just go out. I tried a bunch of different settings for gass flow pre and post and a few different sized cups no difference Attached ImagesLast edited by chrisbmx68; 05-10-2008 at 06:01 PM.Reason: added picture
Reply:the 2 beads that don't look like bird poo are the old ones. I did everything the same this time around cant figure it out
Reply:id be suspicious of the gas
Reply:I don't tig Al.  Just curious is you are withdrawing the filler from the gas between dipping or is the rod dirty.
Reply:Did you remove the oxide from your aluminum before you started welding? I can see some impurities. It's either improper cleaning or you have the wrong shielding gas, IMHO.
Reply:Angle of the torch right, approx 60 degrees, running ahead of the weld and the filler about 10 degrees from the surface in the left hand?Enough current 10l/min gas? Aluminium should be welded hot and fast for a nice looking weld.Looks like my first welds when I had the torch in the wrong angle.
Reply:that piece of aluminum was spotless before I tried to lay those beads, I prob didnt have the angle of the torch perfect but as far as I can tell I was doing everything the same as when I layed the 2 beads that are signifigantly better. I also forgot to mention that I used a 3m brillo pad thingy to rough up the filler before hand
Reply:there are some good beads there, looks like you added the filler prematurely. Establish a puddle before adding filler. If you cant build a puddle then its not hot enough.Bill
Reply:also, looks like the cup is too far from the material which is why there is so much porosity there. The tungsten should not be sharpened for aluminum and should not stick out from the cup as you would for steel.
Reply:I would suspect that your arc is too long, causing you to lose gas coverage...or the wrong gas.
Reply:Thanks for the tips guys, I am really leaning toward the gas at this point. It seems like im doing everything close to correct, and with an old bottle of gas same filler tung settings etc I have laid a bunch of beads that went totally contaminated. I went down and tried a few more passes after my last post with the same result and i made sure the filler was really clean too frustrating
Reply:So it only does it when you add filler? If you run the torch along and melt the base metal but not add filler it is fine? If it is the gas just melting the base metal without adding filler would contaminate as well. If it goes crazy only when you add filler, try some different filler. Or cut a thin slice of the base metal and try using as filler just as an experiment.
Reply:good point I will try that. Thanks again for the tips
Reply:It could be that when you add filler, your focus shifts away from your arc length...and you long-arc it and loose gas coverage.
Reply:Originally Posted by EngloidIt could be that when you add filler, your focus shifts away from your arc length...and you long-arc it and loose gas coverage.
Reply:Im not an expert on aluminum but it looks like either wrong gas (but I always use pure argon) or tungsten is out to far.As said by CHENRY:you cant weld on a thingamajig like that. are you even certified to do thingamajig welding ? I once saw an improperly welded thingamajig fail and eleventy twelvoteen things got ballywhacked. I dont think i would risk it.
Reply:You haven't done any alum recently. Did you remember to switch back to AC?Do you have a pedal? Can you hear gas flow when you hit it?9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:If you produced good beads with the old gas, then got the tank refilled, and now you produce bad beads... what else might be different, other than new gas?
Reply:To me it looks like DCEN not AC Also looks like no HF check your machine setup AC HF on tungsten out about 1/"8 beyond the cup gas flow at 20 CFHI know it is not contamination from the plate (given that you made welds on it before) Go back to basics! Check all the things you "know" are not the problem and fix the one that is.1 in 1000 cylinder fills gets mislabeled or contaminated.
Reply:Its been a few weeks since i messed with aluminum but the best beads I can lay are 100% worse than the first I ever did. I have gas its on ac etc im doing everything "correctly" just cant get an uncontaminated weld It hasto be the gas, or the AC functionality of my machine is breaking
Reply:what gas are you using?machine?If you feel strongly that you have bad cyl of gas exchange it
Reply:check your gas lensHave we all gone mad?
Reply:Incorrect gas (argon/CO2) would fry the tungsten pretty quicklyContaminated argon or a leak in the system...  try a spot weld on some stainless, should come out colour free i.e. no heat tintThe etched (cleaned) zone is clearly visible in the pics so i doubt it's the machineLooks to me like you're melting the filler with the arc and (as several others have said) arc length is excessive
Reply:I will keep at it then thanks for the advice.-Chris
Reply:Originally Posted by hotrodderIncorrect gas (argon/CO2) would fry the tungsten pretty quicklyYou said you replaced your gas, have checked to see if all of your gas line and flowmeter connections are tight and have no leaks?  I have seen this before when there was a loose fitting, or leak and it was sucking air into the shielding gas.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......