1rst try at aluminum AC TIG following the pointers you guys gave me...

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So I hacked up a piece of aluminum I bought yesterday and following the pointers you guys gave me I tried my first butt joint with AC TIG on aluminum.I also tried a corner joint, sorry for the bad picture.  As you can see, I wasn't too successful at that one.I tried a few filet joints but I didn't take pics 'cause they sucked.  I can't get a decent filet joint to save my life even on mild steel (I'll review the technique and practice some more I guess).Any suggestions or comments on the pics I posted?Thanks in advance for any input.One quick question, I sharpened my electrode but after a little while the end balls up, is this normal?  ThanksLast edited by x1rider; 10-12-2007 at 03:23 PM.
Reply:the balling is normalexcellent for a for a 1st attempt  advice, work with larger coupons. that'll give the heat somewhere to go and make life easierthe bead looks pretty clean but it's hard to tell with the light reflection. as long as there are no black specs you have good cleaning.run some beads on a piece of scrap at different balance settings (try more EN). this will determine the minimum amount of EP needed to get a clean weld. not enough cleaning (EP) will result in black specs in the bead and a sluggish weld puddlehave a look at the miller website. theres a free TIG hand book (in the resources section) that covers loads including torch and filler angles- probably the cause of your problems with fillet welds
Reply:Thanks for the advice, I'll experiment running beads with different balance settings and see what is the best for my application.  I printed the TIG handbook from the Miller website, I'll review the torch and filler rod positions and try again.
Reply:They look great for first try , corner fillets in Ally with Tig always look bigger than you would expect at first...well they did with me.At the end of the day its all practice.As hottrodder said long welds will give you the experience of backing off your amps as the ally heats up.A good guess is better than a bad measurement
Reply:Looks pretty darn good! Not so tough, is it? Fillet welds give me hell sometimes too with thin Al. Try cranking up the heat a little and really blasting it at first. Start your puddle as quick as possible on the horizontal piece, then real quick puddle on the verticle piece and dab some filler in at the same time. Once you get the two pieces joined you got it whipped, back off the heat a little and push the puddle. The verticle piece likes to burn back on me if I'm not real quick about that first puddle. Is that the problem you were having?Miller EconotigCutmaster 38Yes ma'am, that IS a screwdriver in my pocket!
Reply:Originally Posted by BrettThey look great for first try , corner fillets in Ally with Tig always look bigger than you would expect at first...well they did with me.At the end of the day its all practice.As hottrodder said long welds will give you the experience of backing off your amps as the ally heats up.
Reply:Originally Posted by Joe HLooks pretty darn good! Not so tough, is it? Fillet welds give me hell sometimes too with thin Al. Try cranking up the heat a little and really blasting it at first. Start your puddle as quick as possible on the horizontal piece, then real quick puddle on the verticle piece and dab some filler in at the same time. Once you get the two pieces joined you got it whipped, back off the heat a little and push the puddle. The verticle piece likes to burn back on me if I'm not real quick about that first puddle. Is that the problem you were having?
Reply:You can aim the arc in the corner.  What I DO is set the tungsten so it won't reach the corner.  It needs to stick out more than if you are welding on a flat.  Use a good size nozzle, 6 or 8.  You still need to keep the tungsten one rods width from the puddle. (1/16" or 3/32") It take some getting used to.  It takes more amps to do a fillet than it does a butt no matter what process you are using or what base metal you are welding.Its a great start!DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RYou can aim the arc in the corner.  What I DO is set the tungsten so it won't reach the corner.  It needs to stick out more than if you are welding on a flat.  Use a good size nozzle, 6 or 8.  You still need to keep the tungsten one rods width from the puddle. (1/16" or 3/32") It take some getting used to.  It takes more amps to do a fillet than it does a butt no matter what process you are using or what base metal you are welding.Its a great start!David
Reply:[/QUOTE=x1rider]I think maybe my tungsten wasn't sticking out enough, the arc was kinda wide and hard to concentrate in one spot.  Almost like the arc was all over the place.  Do you run the cup on the metal (direct contact between cup and metal)?  Pardon my ignorance but when you speak of the nozzle, do you mean the ceramic cup?  Thanks for the information.[/QUOTE]An arc jumping around can indicate you didn't clean the ally enough also. I use scotch brite belts on my linisher but a Stainless Steel brush also works ...never a mild steel brush.I'm not a fan of it but others on this board (who I may add have demonstrated their superior welding skills compared to mine through pics I may add) swear by acetone and the such as a final clean.I also stick my electrode out a bit further in a corner fillet than usual and often aim for the center unless there is a considerable difference in wall thickness or the bench is acting as a heat sink.A good guess is better than a bad measurement
Reply:As Brett said, many use acetone to final clean the part. I would say, in most cases, if you can, it is a good idea. If it is a critical part, it is simply done that way. If the aluminum is old, or dirty, you do need to be sure the oxide layer is scrubbed clean. And, acetone will clean off any grease. Honestly, I think the acetone simply wets the rag to grab the oxide dust from the part, and the good byproduct is that the acetone leaves no residue. I find that for corners, I like the tungsten to be pretty sharp, but for sure.... CLEAN. I am the Zen Master of sticking filler into my tungsten. When I have corner work to do, I am sure to clean up the tungsten, and get a good grind on it, so I can have a clean arc. I don't worry too much about stickout, but I do try to concentrate on keeping the tungsten consistently close as David pointed out. If you wander a lot on the distance, you will see the arc widen, and the is on his way to goof you up!!! Your flat welds look good, so keep up the practice. I also agree with Joe about the blasting it to get the puddle started real quick, then back the heat off. Also, if you have waveshaping, try to get the downslope timing as close to 0 as you can. If you downslope too much, the aluminum will blob out on you sometimes. I run my downslope at .2 second.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Thanks for the many pointers again.  I use a SS brush and acetone for the cleaning but it is old aluminum that I picked out of a scrap pile.I'll try what was suggested and I guess that the only thing that will make me "get it" is practicing.  I need to get bigger pieces of metal though, the ones I use tend to melt quickly.