Liquid Aluminum Control

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Hi all,I'm new to Aluminum tig and I've found a fair amount of trip and pointers on this website and others. I'm having some trouble though and wanted to ask for advice.I've been trying to get the popular stack of dimes look but I am unable to. When I try I just get a solid string of metal or amorphous blobs, not a neat concentric look. The metal seems to just flow wherever. Are there any tips for controlling the puddle more effectively?Attached are some pictures of my welds and linked is the weldingtips and tricks video that shows the look.EditSorry my mistake. I meant to include the info but then completely forgot. Here's the listMiller Syncrowave 180sd1/16th Pure Tungsten100% argon at 20 cfhAC (60 percent electroide negative 40 percent positive)1/16th plate aluminum1/16th aluminum filler rod50-80 amps Foot pedal controlStainless Steel wire scrub on stainless steel table before welding. Electrode is melted into a round point before welding. Attached ImagesLast edited by canyon289; 07-28-2011 at 10:46 PM.
Reply:What machine and settings are you using?  What tugnsten and size?  What type of amperage control.Zap,When someone goes to start a new thread in this section, can a window popup and ask if you have included this info or not?  Seems like the first several posts in a lot of threads regard this unneccesarily.EDIT:  Looks like the metal is not very clean and you have contamination issues at the start.  Also, it looks way too hot at the end of the weld.  Show a pic of your tungsten before and after.  I bet it is a balled up mess by the end of that.Last edited by jmtebbens; 07-28-2011 at 10:42 PM.
Reply:I put the info up. Thanks for reminding me what a bone headed mistake
Reply:It looks like you need to clean more. Alum oxide melts at a much higher temp than bare alum. By the time you get the top oxide layer to melt, the pure alum underneath is already a liquid. this plays he11 with trying to get good beads when starting out. Also with alum you need to pour a ton of heat into the pieces all at once to get the bead going and then back down and move. If you take your time and try to build a puddle like you can with steel, you simply heat the whole plate up and then have puddle control issues. Since alum is such a good heat sink, you need to dump the heat into the weld faster than the alum can disipate it and then move to outrun the heat. You really need to have heat and puddle control down cold to do alum easily. If you can't control the puddle with steel, you will find trying to do alum to be very frustrating.Last edited by DSW; 07-28-2011 at 11:33 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thanks for the tips. Due to budget cuts my school is closed Friday through Sunday but I'm gonna get back on this Monday.As far as outrunning the heat goes, the youtube video shows the welder using a step pause technique and he mentions that he doesn't pulse his pedal. Is he just doing this rapidly enough to outrun the heat?
Reply:Still needs to be cleaner.  You have to get through that oxide layer.  In your above pics, you can see where it is burned off near the start of the weld.  That is what you need before you start.Acetone will help you clean as well.  Remember, your brush is ONLY to be used on AL.  I really prefer 70/30 as well on the balance.Practice, practice, practice.  It is doable, even with less than clean AL with enough hood time:
Reply:If you are running High freak when welding aluminum the aluminum oxide should mostly be blown off. That's what its for to clean the oxides off. The stack of dimes is not necessary to make a good weld it just happens when you have really excellent control of feed and heat and torch movement. Many times when I wanted really smooth beads I would go back over the bead with the torch flame and smooth the bead out. Especially if it was going to be polished.  Mac
Reply:Originally Posted by Tool MakerIf you are running High freak when welding aluminum the aluminum oxide should mostly be blown off. That's what its for to clean the oxides off. The stack of dimes is not necessary to make a good weld it just happens when you have really excellent control of feed and heat and torch movement. Many times when I wanted really smooth beads I would go back over the bead with the torch flame and smooth the bead out. Especially if it was going to be polished.  Mac
Reply:Originally Posted by LawsonWeldingLLCINCORRECTThe HIGH freq is not to clean the oxides off for one, the high freq refires the arc everytime it switches from dcep to dcen The dcep allows the electrons to flow from the work to the tungsten dcen switches to flow to the work. Depending upon the Hertz the machine is running at depends how many times a second this happens.
Reply:Correct , Dcep pulls the oxides up off the plate with the flow of electrons, Dcen switches and the electrons flow from the tungsten to the plate and this is where we get our penetration from.I forgot how to change this.
Reply:High frequency can help with puddle agitation(DC pulsing freq). More of a useful thing on stainless than aluminum. In AC(switching freq) though it can really tighten up the arc and give you a narrower deeper arc that lets you focus heat better. On dirtier material I actually prefer to turn the frequency down to around 50-60, It seems to help the puddle flow a little better and for some reason I have an easier time working with dirty metal (castings) with a lower frequency.
Reply:Thanks guys!The tips you gave me helped a lot. I was able to get better at puddle control and consistency when running beads but I still run into major problems joining two pieces of aluminum. The trouble I'm having is bridging the puddle between both pieces. If I concentrate on removing the oxide on one piece the other will melt or vice versa. If I try adding filler the puddle shies away from the oxidized piece. I've uploaded pictures of this on a lap joint.Here's my settings copied again for referenceMiller Syncrowave 180sd1/16th Pure Tungsten100% argon at 20 cfhAC (60 percent electroide negative 40 percent positive)1/16th plate aluminum1/16th aluminum filler rod50-80 amps Foot pedal control Attached ImagesLast edited by canyon289; 08-02-2011 at 01:33 PM.
Reply:Clean, clean, clean, and make sure the fit up is good.
Reply:Slam the peddle down and get a bead going , add filler to compensate for bead size....move forward....simple concept......if the bead dont form try more heat....simple oh and jump that tungsten size up and wire brush those pieces, dont make it harder than it really is.I forgot how to change this.
Reply:Learning with 1/16" is not easy. You might try 1/8" instead. It won't burn up quite so fast, so it's a bit easier to learn on. Besides what's been mentioned above, good fit up will be important. It looks like there may have been a gap between the two plates. The students at the tech school run into this some times if the guys shearing the plates are lazy. If the plates have a bow and don't lay flat, lap joints and outside corners are tougher to do than they need to be. getting the puddle to bridge that gap can be a PITA especially if you want to maintain a good bead appearance..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan