Why do my AL tacks crack

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I think it is just this aluminum I'm working with right now because it has not happend to me in the past. Is this a lack of preheat? It seems to help if I put more filler in. Any info would help. Not sure what kind of aluminum it is. Bought it off CL for 100$ for 40 feet of 1/8x 1.5 wide square tube. New metal. 5356 filler
Reply:What procedure are you using ....gun or tig?Measure with a micrometre, mark with chalk,  cut with a torch.Never force anything...just get a bigger hammer.RoyOld Airco buzz box approx 1974Lincoln mig pack 15Lincoln 175 square wave1954 9" south bend lathe
Reply:
Reply:longer tacks
Reply:Tig. Couldn't see doing it any other way
Reply:What do u mean longer tack?
Reply:i think he  means more heat  and little more filler
Reply:Aluminum short cracks really bad. You may need more filler on your tacks. Also if you notice the center of your crater is really sunk in, you can slowly ease off the pedal and allow the puddle to cool evenly. If you get in this habit early on, you'll avoid cracked welds tooTeach Ag Mech - Mike At Home:Lincoln Electric AC225Miller Challenger 172Gas AxeWork:eclectic bunch of 90's vintage blue boxes
Reply:Yeah I'm looking at your photo, you need more heat. hit it with a wire wheel. Put D-nature alcohol and use rag that wont leave threads every where. Actually to much filler metalcan cause a crack. Not enough penetration. You'll get it. Hey at least your not welding aluminum with water trapped inside another plate like I did last week. lol.http://markwilliamhowell.blogspot.com
Reply:I was trying to let off the petal slowly and sometimes it still cracks. Sometimes it cracks only half way across or quater of the way across the tack. Seems like if I wash the puddle around a little and blend it into the rest of the metal it seems to help. On steel I put the amps to about double I would normally weld and floor the pedal real quick and works like a charm but aluminum seems alot different.
Reply:hum. I usually go hotter with aluminum tig tacks.
Reply:Mark do u weld with a transformer? How much amps would u use for this 1/8th. I'm using 175 +
Reply:Yeah man I've always set machine super hot and stomp for the tacks. Make sure everything is super clean. You don't want that much metal on such thin gauge tubing. when you get a crater crack at the end the weld is done it will crack all the way down (linear crack)
Reply:I mean every machine is different man. numbers really don't do it for me. it looks as though you need more heat.
Reply:Ok I will try running my tacks in hotter. Can u tack aluminum with a quick bump of the pedal?
Reply:Originally Posted by motolife313Ok I will try running my tacks in hotter. Can u tack aluminum with a quick bump of the pedal?
Reply:Alright I'll give you an example hope this helps. Lincoln Power Tic on AC no pulse setting pure argon gas lense #7 cup 100%tungstan 1/8 aluminum setting for tacks around 150get a little cleaning action then go all the way. I usually dab the filler twice on tacks. and release the pedal quickly. Hope that info helps some what.
Reply:Personally I would never tack thin aluminum with out filler metal
Reply:I know Jodie does it sometimes but I've only seen him do it on thin aluminum like 1/16.  The reason it might look a little cold is I didn't want it bigger then my weld will be. I might have to get over that. Do I need to wait for the 2 puddles to join or is it ok to jab the filler in real quick while there are 2 puddles?
Reply:Originally Posted by motolife313I know Jodie does it sometimes but I've only seen him do it on thin aluminum like 1/16.  The reason it might look a little cold is I didn't want it bigger then my weld will be. I might have to get over that. Do I need to wait for the 2 puddles to join or is it ok to jab the filler in real quick while there are 2 puddles?
Reply:Ok I'll try beefing them up and ill report back with my findings. Thanks guys for replying so quick!!!
Reply:you need to brush the bits of blue paper towel off before you start welding. A solvent wipe is insufficient to clean aluminum for welding.  Use a small stainless brush and brush off the oxide layer.  6xxx extrusions are the worst when it comes to brushing the oxide layer off.  As you brush, you will feel the brush bite into the metal instead of just slide across.  Once you know what to look for, you will be able to see the surface transition from unbrushed oxide, to brushed oxide, to brushed bare metal.  You kinda have to brush the s**t out of it with 6xxx tubes.  Try 10 seconds of brushing per side (four sides of tube) to start.  Resist the urge to just hammer on it with a power brush, as that will just shove the oxide into the base metal.  Brushing in the same direction helps a lot too.  Keep your AC balance somewhere around 55% EN to start (around 6-ish on the dial for transformer machines), and move more toward a balanced arc if you still can't get the tack to wet out quickly.  Also, autogenous welds are impossible with 6xxx aluminum.  I love 5356 myself, and usually when I get tacks breaking it's because I didn't get it enough penetration.  Nearly all extrusions (tubes) are 6xxx, and there needs to be a certain amount of dilution of the base metal with silicon (4043) or magnesium (5356) to prevent the hot short cracking that 6xxx alloys are susceptible to.    When welding 3003, it tacks up just great with no filler, provided your fit up is snug. You asked about waiting for the two puddles to join.  Sometimes they will, but the surface tension is pretty strong, and mostly they will just pull further apart from each other.  It's a real problem sometimes getting the arc to evenly heat both pieces when the fit up has even a sub-millimeter gap.  I feel like a snake-charmer sometimes trying to get the arc to evenly heat both sides, so what I do is let the arc heat the side it wants to, let the puddle form, then stab the filler in there and use the filler as a thermal bridge to conduct the heat to the other side.   If your fitup is dead nuts snug, the puddle will bridge the (nonexistent) gap and the puddle will flow just fine, but mostly you have to deal with some amount of gap.Read all you can on Alcotec's website http://www.alcotec.com/us/en/educati...num-Alloys.cfmLast edited by bebo; 11-14-2014 at 08:53 AM.
Reply:Originally Posted by beboyou need to brush the bits of blue paper towel off before you start welding. A solvent wipe is insufficient to clean aluminum for welding.  Use a small stainless brush and brush off the oxide layer.  6xxx extrusions are the worst when it comes to brushing the oxide layer off.  As you brush, you will feel the brush bite into the metal instead of just slide across.  Once you know what to look for, you will be able to see the surface transition from unbrushed oxide, to brushed oxide, to brushed bare metal.  You kinda have to brush the s**t out of it with 6xxx tubes.  Try 10 seconds of brushing per side (four sides of tube) to start.  Resist the urge to just hammer on it with a power brush, as that will just shove the oxide into the base metal.  Brushing in the same direction helps a lot too.  Keep your AC balance somewhere around 55% EN to start (around 6-ish on the dial for transformer machines), and move more toward a balanced arc if you still can't get the tack to wet out quickly.  Also, autogenous welds are impossible with 6xxx aluminum.  I love 5356 myself, and usually when I get tacks breaking it's because I didn't get it enough penetration.  Nearly all extrusions (tubes) are 6xxx, and there needs to be a certain amount of dilution of the base metal with silicon (4043) or magnesium (5356) to prevent the hot short cracking that 6xxx alloys are susceptible to.    When welding 3003, it tacks up just great with no filler, provided your fit up is snug. You asked about waiting for the two puddles to join.  Sometimes they will, but the surface tension is pretty strong, and mostly they will just pull further apart from each other.  It's a real problem sometimes getting the arc to evenly heat both pieces when the fit up has even a sub-millimeter gap.  I feel like a snake-charmer sometimes trying to get the arc to evenly heat both sides, so what I do is let the arc heat the side it wants to, let the puddle form, then stab the filler in there and use the filler as a thermal bridge to conduct the heat to the other side.   If your fitup is dead nuts snug, the puddle will bridge the (nonexistent) gap and the puddle will flow just fine, but mostly you have to deal with some amount of gap.Read all you can on Alcotec's website http://www.alcotec.com/us/en/educati...num-Alloys.cfm
Reply:I always brush by hand until all the lines go away and until its shiny metal. And I wipe first with a acetone. Othere wise u with be smereing the dirt in the metal right? I gave that a quick wipe down after I brushed it bc I was wiping other areas and the rag was still wet. I'm gona start using a washcloth bc it always tears up the shop towel so quick. I wipe down my filler every time to. Those are really nasty! And when I preheat I brush a little after that to. A pro told me to do that
Reply:Originally Posted by motolife313Ok I will try running my tacks in hotter. Can u tack aluminum with a quick bump of the pedal?Nice man! Way to go on finding the right settings! I new it could be done. But my machine maxes out at 230. I will give it a try on practice peices. I love doing it on steel. U gota floor it fast tho. On steel u can put ur finger on it almost right away after you speed tack it bc it does it so quick
Reply:Dave is showing off that he can vaporize a whole engine block in ten seconds, he's right, amp for amp, inverters tack quicker. I doubt anything tacks quicker than about 500 amps he can generate instantaneously. I do autogenous tacks on 16 gauge with a 280 and with a 310 amp transformer machine. Hot aluminum is very weak, You need lots of tacks. They can be very small, you just need a lot of them. Splattering acetone al over concerns me, but Zapster uses a toothbrush sized stainless brush with acetone to float contaminants away as they are scratched loose.I set as hot as the machine will go. If it takes a second, that's too long for a tack without filler. Puddle too fast to let heat dissipate, or aluminum to oxidize.Last edited by Willie B; 11-14-2014 at 10:00 PM.
Reply:What's wrong with acetone?
Reply:It's flammable, and soaks through skin to dissolve your internal organs. Use nitrile gloves, avoid breathing fumes, (use outdoors or with ventilation).
Reply:How do you prep your aluminum to clean it? I should get in the habit putting gloves on. I not afraid to try new things!
Reply:Originally Posted by motolife313How do you prep your aluminum to clean it? I should get in the habit putting gloves on. I not afraid to try new things!
Reply:I've whatched it like 3 times. The valve cover. I love that guy! Jodie is the man!
Reply:New material with light oxidation, I use gloves, a paper towel, pour a little acetone in a small aluminum tray, and wipe it down. If I don't want scratches, I leave it at that, set balance to 70% EN, (30% EP). If scratches are less a concern I use a Scotch bright pad. Then I can do 75 or 80%. Heavily oxidized material gets a 4" grinder with either a poly abrasive paint stripper disc, Home Depot has Avanti, or Avani, Norton Calls them Blaze, Radnor sells them, Sears has them, Don't use a heavily worn one on aluminum weld prep, as you get close to the backer disc the adhesive they laminate it with messes up your weld. An alternative is a fine brass brush on a 4". In any case keep the pressure light to avoid burnishing contaminants into the joint. It's catch 22, wiping last thing with acetone leaves millions of towel particles, abrasive of any kind may leave other contaminants.
Reply:Originally Posted by motolife313Nice man! Way to go on finding the right settings! I new it could be done. But my machine maxes out at 230. I will give it a try on practice peices. I love doing it on steel. U gota floor it fast tho. On steel u can put ur finger on it almost right away after you speed tack it bc it does it so quick
Reply:What's so bad about microscopic scratches? Do u use the purple pads? I would think the pads would clog up fast. I usually snip my filler rod at the end to where the contamination to
Reply:And why did u say splattering acetone concerns u when u use it urself lol
Reply:I use it with care. Some use it like toothpaste, a small stainless brush, liberal splashes of acetone, scrub the hell out of it.
Reply:I started puting very little pressure on my brushes and I works better for me that way. And a 1/8 tungsten. I keep arguing with my Machinest about using red tungsten on AL. He thinks it will spit tungsten in ur puddle. He is a welder also. But I know alot of good welders that us it on every thing. Zapster uses it to. What do u think. I think pure is crap. I use a transformer
Reply:Pure is fine on a transformer. I like lanthanated personally. I use it for everything. Transformer or inverter. Sent by a dumb smartphoneTeach Ag Mech - Mike At Home:Lincoln Electric AC225Miller Challenger 172Gas AxeWork:eclectic bunch of 90's vintage blue boxes
Reply:I know it works but the arc is not small. It's alot brighter but fans the arc out. 2% lanthanated is pretty good but not as good as red and I think u need more amps and its not very bright with the blue. I'm playing with 1.5 lanthanated right now but have nothing to say about it bc I don't have much time with it. I doing a project right now and I know what the red does. E3 seems pretty good and balls small on its own.
Reply:With a transformer, pure is OK. I'm not convinced it is the best choice. Slight balling is not a problem on AC.
Reply:I don't think tungsten is a big issue at all. I have always done the switch to pure when welding aluminum because that is the right way. Then I did some aluminum welding with red and didn't notice much difference. Now with my new welder and torch the guy had some sort of gray tungsten in the torch, weld aluminum and steel with it and know what? Can't tell the difference between the green, red, or gray now.The only thing I noticed is how the tungsten acts itself. The green and gray ball up on the tip, the red just gets dingleberries on the tip. Thats it, while welding I couldn't tell you what color tung is in the torch.12v battery, jumper cables, and a 6013.I only have a facebook page. https://www.facebook.com/pages/VPT/244788508917829
Reply:the gray is ceriated. it works OK. if you're balling the end on purpose, or running a transformer(which will ball the end on its own) the thoriated will get that thorium spike and really mess with the arc after a while. I was taught to switch to DC+ and ball the end anyway.  Now I just sharpen the thing and let it ball to where its gonna go on its own.  if it calls  a little on my inverter i don't cry about it.  If I really neeeeeed to focus the arc, i'll jack up the frequencyTeach Ag Mech - Mike At Home:Lincoln Electric AC225Miller Challenger 172Gas AxeWork:eclectic bunch of 90's vintage blue boxes
Reply:The grey is ceriated.  That's mostly what we use at work for everything
Reply:I wonder what John Marcella uses? Anyone know. Owner of marcellas manifolds that guy is a stud
Reply:Originally Posted by motolife313I wonder what John Marcella uses? Anyone know. Owner of marcellas manifolds that guy is a stud
Reply:Is there a reason ur talking it the wrong way? Or are you trying to cover somthing up by being a smart ***
Reply:Originally Posted by motolife313Is there a reason ur talking it the wrong way? Or are you trying to cover somthing up by being a smart ***
Reply:I can tell the e3 is not that good on low amps on DC. I close my eyes and switch them around in my hand then put them in the torch. I want to only have 1 kind of tungsten!!!!!!!!!
Reply:Originally Posted by motolife313I wonder what John Marcella uses? Anyone know. Owner of marcellas manifolds that guy is a stud