TIG is hard!

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Well I picked up a syncrowave 180 for a sweet deal and finally got everything I need to start welding aluminum.  Many years ago I use to stick weld and thought I was pretty good at it but this is my 1st time trying tig on aluminum.  Hopefully you guys can give me a few pointers.I’m welding 1/8 aluminum, Using 1/16 100% pure tungsten rod and I tried the power between 90 and 130 just experimenting trying to find the right setting.  I’m not using any filler right now, I’m just trying to get the feel until I can lay decent beads. Yesterday I couldn’t even get it to form a puddle, then suddenly it would melt a hole. And the arc was huge and all over the place. But I found out the rod I was using was way to big not to mention I don’t even know what type it was (came with the rig) so the new 1/16 pure ones seem to be working much better.So today I was finally able to get some puddles going. But It seemed to have a tendency to form sunken depressions instead of raised beads? What causes that? Going to slow or too much heat? Or is that what happen when no filler rod it used?Then I tried joining to pieces together by laying them down side my side. I was somewhat successful but on my best looking weld (which wasn’t very good looking) I had a small crack right where the seam was. What causes that? Going to fast or too much heat? Or maybe I need a LOT more heat and need to go even faster. 90-100 seemed too low and hard to form a puddle. 110 to 120 seemed about right but it’s hard to know because I’m not really sure what I’m looking for yet.  130 seemed a little hot but if I was at the right height and moving the rod well it seemed like it might work too.  Am I at least in the ballpark for 1/8 aluminum?Thx in advanced.
Reply:going too slow and too much heat makes sunken depressions because going too slow makes too much heat and it could also be from trying to fuse.. don't even try to fuse with tig aluminum there's no point it's like impossible.. lol..  form a ball on the end of the tungsten by arcing it on brass.. i would use a 1/8 tungsten zirconia for aluminum and like 200 amps on high frequency on dc reserve.. i don't know what causes cracks tho.. maybe from rapid cooling?.. also use a half inch gas cup (#8)
Reply:Thx for the tipsBy just welding on the aluminum a nice ball formed all by it’s self.  I don’t have any brass around but would aluminum work?  Someone told me to use a penny to form the ball. It’s doesn’t seem to be a big problem because I can just weld on some scrap and form the ball.I’ll get some filler and try it again. Do I need to know exactly what kind of aluminum I am welding and and get the same filler or is there a general purpose filler that would work? I’m not welding anything could cost lives so it doesn’t need maximum strength .
Reply:ya you can make the ball at the end with scrap cause you're using pure tungsten and it melts easier than tungsten zirconia and no i don't think it matters for the type of aluminum.. i'd just use 5356 rod
Reply:Sounds like you are not getting the aluminum clean enough.  The oxide coating that forms on the outside of aluminum has a melting point that is much higher than aluminum (2 or 3 times higher..can't remember for sure)But if you don't get it cleaned off when you go to start your puddle you will pretty much bol the insides before the outside melts.  So then when you do get the outside "skin" to melt the inside will just pour out.  Same with the sunken depressions, sounds like the inside is meing beofre the outside.The hardest part about welding aluminum is getting it clean enough.Scrub it with a stainless wire brush or scotch brite pad..and only use that one for aluminum.  Then wipe it down with acetone.Once you get it clean it gets much easier.LaterRandy
Reply:Not sure if I missunderstood but are you new to tig?If so, you should probably try to start off on carbon steel, then stainless, then aluminium.
Reply:Yes I’m very new to TIG but I have some good news today.I actually made my 1st bead that actually looked like a bead on aluminum. Using a filler rod I managed to weld 2 pieces of 1/8 aluminum laying side by side together.  The bead was taller then needed and it didn’t have as many ripples as it should but it was a bead none the less. I think I’m starting to get the hang of things. I’m out of 1/8 scrap aluminum so Monday I’ll have to get some more to practice on. I have some ¼ inch aluminum but I think that’s pushng the limit of my syncrowave 180. I think the 1/16 tungsten rod is also too small for ¼ inch because it would melt before the aluminum would. So I gave up trying to practice on the thicker stuff. I also think I noticed the “skin” forming over the aluminum and making it hard to melt. It’ s a white milky looking film right? Since I’m just practicing I haven’t been cleaning the aluminum all that well. A dirty wire wheel is about the extent of it. I’ll try actually try using acetone next time and the correct size filler rod. I even tried out stick welding on some angle iron. I can tell I’ve lost my touch because my beads didn’t look very good and not very uniform. But the welder worked great. 1st time using DC instead of AC too. Noticed it sounds a lot different but couldn’t tell any difference form electrode positive VS negative except one setting seemed to consume the rod faster but maybe it was in my head.Anyway tanks for the tips so far and maybe next week I’ll take some picture so you guys can give me more advice. Theirs no point right now but in a week I think I should have the basics.
Reply:The key to cleaning aluminum is using a stainless steel brush or wheel that is only used on aluminum.This breaks the surface oxidation which actually has a higher melting point than the base metal.Unless your aluminum is oily you shouldnt need acetone, unless of course you like the smell or the way it dries out your hands.    Hang in there and keep practicing!!
Reply:Originally Posted by fl_riderThe key to cleaning aluminum is using a stainless steel brush or wheel that is only used on aluminum.This breaks the surface oxidation which actually has a higher melting point than the base metal.Unless your aluminum is oily you shouldnt need acetone, unless of course you like the smell or the way it dries out your hands.    Hang in there and keep practicing!!
Reply:The more I use my syncrowave 180 the more questions I have.1) when using TIG on angel iron (mild steel I guess) say 1/8 inch what’s the best setting? AC? DC+ or DC-? I know AC is for aluminum and DC for steel but DC seemed to heat up my tungsten much faster. 2) What’s the best tungsten to use for steel? And what size and amp for 1/8.3) Is there a nice tungsten chart on the web so I don’t have to keep bothering you guys?4) Now for stick welding on steel, What’s better DC+ or DC- and why?Thx in advanced…..again.
Reply:For tig welding steel, you want your torch negative and the work positive, which I believe is DC Negative.  Picture the electrons flowing from the negative torch to the positive workpiece.  The heat goes into the work, not the tungsten.  If you reverse it, you tend to overheat the tungsten and melt it.  You will know pretty quick, as the tungsten will melt fast.For tungsten, old school is a 2% throriated tungsten, but due to a very low level radiation hazard, 2% ceriated seems to be taking over.  My guess for 1/8" is you would probably want to run a 3/32" tungsten.  It is good from about 60 to 130 amps or so.  Make sure to sharpen it, as it will keep a point in DC.Here is a good source for tungsten information:http://www.ckworldwide.com/technical.htmI can't give you much advice about stick welding.
Reply:Most likely all the aluminum problems you are describing is comming from a nice thick layer of oxidation on the aluminum.  You can use an acid to etch the surface of badly oxidized metal (or for anodized) and get rid of most of it, but like others have indicated you should degrease (if necessary), and at a minimum, really clean the surfaces you intend to weld with a stainless brush.  It should be shiney and bright and done right before you weld.  If you are having problems with sagging, it's because the oxidation is acting as a sack around the aluminum.  You are melting the inside before the outside, because aluminum oxide has a melting point WAY, WAY above the base aluminuim.  The inside is liquid, the outside is solid, but unable to hold the form....and then splash...it's a hole.  Clean it good and this problem will be greatly reduced or disappear entirely.  I always use ac with high freq on continuous for aluminum.  I hear of people using dc tig on aluminum, but ac works and works well.  I use black or green banded electrodes.  They work pretty good and I havent experimented much because of that (that's more preference than anything else, though).  Really, I have found that the tungsten type (once properly shaped) doesnt make as big a difference as the operator.  Just get any one that is rated for AC, and if you want to experiment get a couple or three sizes (along with the right collets and stuff).For steel, you generally want the heat in the workpiece, else at moderate to higher amperage, you will be eating up tungsten like crazy and can damage some torches (if you arent using a torch rated for pretty high amps).  Straight Polarity (or Electrode Neg) will throw negative electrons (btw all electrons are negative) from the electrode to the base metal, heating the base metal.  There are situations for reverse polarity, but...this is probably a good place to start.  If you can work fast, you can use more heat and make really nice beads with a narrow heat affected zone, without burning through.  If you are learning, you are probably going to want to slow down and turn the heat down, just until you get the knack.  Slower means more heat buildup in the metal, but also more room for mistakes and adjustment.  Just a thought or two.Those are supposed to be fantastic machines....Last edited by smithboy; 10-06-2005 at 01:46 PM.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Originally Posted by guy-finnigan i would use a 1/8 tungsten zirconia for aluminum and like 200 amps on high frequency on dc reserve.. i don't know what causes cracks tho.. maybe from rapid cooling?.. also use a half inch gas cup (#8)
Reply:As far as I know, it's not the recommended method.  I have yet to see a chart or a table that specifies dc tig on aluminum.  All are AC with hi-freq + pure argon.  You might want to investigate this more before you try it on anything important.Smithboy...if it ain't broke, you ain't tryin'.
Reply:start with aluminum...its a blast..remember to move your torch..this nonsense that you should learn oxy open flame braze is bull.....imho...jim..good luckwww.arctekmarine.com
Reply:My suggestion to you is, do you know of any welders who could show you a  bit of welding. Where are you located ? If near wisconsin I'd gladly show you.Aluminum is for some very troublesome. Certain grades of aluminum must be dilluted with a sufficent amount of particular filler wire or weld cracking will result. 5356 is a good choice for you to have, 4043 is also good and used for cast alum. repairs and 4047 is even better for crack sensitive areas.Many people weld aluminum with not enough heat. As you stay on aluminum waiting and waiting for puddle to form prety soon metal will or may drop. Aluminum has a good heat transfer and therefor the need for a high heat to area to form puddle. I at times pre heat thicker parts, or used to do this for I now use pure Helium to weld thicker sections of alum or copper. The intense heat created is awesome.Actually Helium was the first gas used in the Tig process but Argon is used more so for its more stable arc, yet when welding at high amps Hel is fairly stable.Back to the welding of alum. yes it should be clean, but I could take a pc. from the steel supplier and still weld it pretty dam good. Try welding a alum casting, small engine cylinder, machine component full of oil, dirt etc.., boat, prop. These items I clean extensively and still there may be issues, for when the arc hits alum. it releases traped gases in casting which creates porosity.You should be able to place 2 pcs corner to corner and weld them fairly easy, as for balling the tip I have'nt bothered for 20 years or more. pure was the old stand by for tungsten but with the sq. waves 2%  and a host of others can be used. Aluminum can be tricky and like I said if you could watch someone you'd have it right away.Good luck JerLast edited by Jerry; 11-03-2005 at 12:23 AM.J P Streets Welding LLC