Can someone please tell me what happened here? (prob. metallurgy related)

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I cut all the pieces I needed to do my intercooler end tanks. The aluminum I used was ordered from onlinemetals.com and the only description I could find was 6061-T6.I have been practicing aluminum TIG for a while now and I was using aluminum bars with markings 6061-T6511 and 5356 rod.I'm by no means the best TIG welder but here is a pic of the results I was getting with the 6061-T6511 aluminum and 5356 rod.Now here is the result I got with the 6061-T6 aluminum, pretty crappy isn't it?  It responded like nothing I ever experienced before, it's like it wouldn't "melt" evenly.Can someone help me with this please?  I noticed the color of the metal I bought online is different from the bars I practiced on.  Is the problem the 5356 rod I used?Any help would be greatly appreciated, thanks in advance.Last edited by x1rider; 03-30-2008 at 01:26 PM.
Reply:Are you sure thats alum. in the last picture?? Better check again. 5356 filler?
Reply:Originally Posted by lars66Are you sure thats alum. in the last picture?? Better check again. 5356 filler?
Reply:Did you plama cut the pieces to length. It appears that the edge still has some dross (slag) if you did. Well if you plasma cut them you need to hit the edges with a grinder and clean them up. --Gol'
Reply:Originally Posted by Go1lumDid you plama cut the pieces to length. It appears that the edge still has some dross (slag) if you did. Well if you plasma cut them you need to hit the edges with a grinder and clean them up.
Reply:No slag..Spray cutting matter..Or Anti Matter Matter should be left behind..Get to the good metal then continue.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterNo slag..Spray cutting matter..Or Anti Matter Matter should be left behind..Get to the good metal then continue.....zap!
Reply:try hitting it with a flapper wheel on your angle grinder, one that says its good for aluminum on it, then try welding it again. your first tig pic looks better than mine though cool.Nothing Ever Got Done By Quitting, Never Give Up.
Reply:You can weld over a plasma cut edge and make it tie into both sides, although it will be a bit more dirty and not weld as easily...It looks more like you're just having a hard time with that type of weld joint to me.
Reply:Originally Posted by EngloidYou can weld over a plasma cut edge and make it tie into both sides, although it will be a bit more dirty and not weld as easily...It looks more like you're just having a hard time with that type of weld joint to me.
Reply:I find it hard to believe the same guy did both welds.  Your second pic looks like you didn't use near enough heat.  When you clean the aluminum, make sure the wheel does NOT contain aluminum oxide.  Its the last thing you want in your base metal.Keep at itDavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:if you just cut it then weld it, it could still be hot cause aluminum soaks it up it could be to hot to weld.  so did you cut then weld right after?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:Originally Posted by x1riderI don't understand, outside corners are the ones I practiced the most and never had any problems with... until now that is...The pool just wasn't appearing and I just ended up smearing molten filler.I'll try cleaning better with a flap wheel like Doug247 mentioned.
Reply:That type of a weld can also happen if you pull the gas nozzle to far away from the work. If you are close you should be melting the base metal, and just filling in the corner. To much angle can also do that.        Sincerely,             William McCormick
Reply:There's several things going on here but the problems aren't caused by a filler/base metal incompatibilityDoesn't look like you're hot enough for a start.Trying to completely finish one joint before fitting the next piece is asking for trouble- the heat required is going to vary lots as you approach an edge. Tack the whole weldment together first before finish weldingAs Engloid said, welding plasma cut edges is possible but aside from being more difficult, (with heat treatable alloys at least) the plasma can cause micro cracking in the HAZ of the cutDon't use a bench grinder with aluminium unless you have specific wheels- the standard wheels are aluminium oxide.Intercooler and radiator cores are typically made from 1050 or 3003 series Al. No problem welding 6061 to them but personally i fab tanks from 3003- it's more than strong enough and far nicer to shape. I would have made that tank out of one piece, tack the cut lines that are necessary due to the shape and then tack the entire tank to the core before final welding
Reply:Originally Posted by David RI find it hard to believe the same guy did both welds.
Reply:Originally Posted by welder155if you just cut it then weld it, it could still be hot cause aluminum soaks it up it could be to hot to weld.  so did you cut then weld right after?
Reply:sorry but were the pieces still hot or coolim guessing cool6G 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:Originally Posted by welder155sorry but were the pieces still hot or coolim guessing cool
Reply:ok so with all that said i saying deff more heat cause i though possibly it was melting away before joining.  so if your using 5356 filler yes it melts different then 4043. 4043 = better melt in but durastic difference in weld color when anodized or any other treatment5356 = not so easy to melt in (more heat) but weld will stay close to the parent metal in color after treatment (but not when annealed)SO basically more heat haha6G 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:ooo,  also to add, i find sometimes i will be tilting the torch towards the filler too much and it melts off the filler before i can dab it into the puddle, and it looked like yours. so aiming the arc close almost  straight into the joint  with the filler at 90 degrees properly helped fix that.Nothing Ever Got Done By Quitting, Never Give Up.
Reply:Looks like you were melting the filler metal with the arc, and blobbing it onto unmeolted base metal.  You need to melt the filler by dipping it into the molten puddle on the base metal.  Maybe you had trouble gettiing a puddle on the base metal because of excessive oxide and the puddle/filler would not wet out nicely.  First degrease with a solvent like acetone, then stainless steel wire brush.  After you tack weld the pieces, wire brust again.  Do not aggressively power wire brush, the intense localized friction heating can cause oxide formation.  Hand wire brushing is fine.
Reply:Originally Posted by pulserLooks like you were melting the filler metal with the arc, and blobbing it onto unmeolted base metal.  You need to melt the filler by dipping it into the molten puddle on the base metal.  Maybe you had trouble gettiing a puddle on the base metal because of excessive oxide and the puddle/filler would not wet out nicely.  First degrease with a solvent like acetone, then stainless steel wire brush.  After you tack weld the pieces, wire brust again.  Do not aggressively power wire brush, the intense localized friction heating can cause oxide formation.  Hand wire brushing is fine.