I have to admit that I didn't concentrate so much effort on cleaning, so I was probably jumping the gun.
What would you suggest as a proper and successful cleaning technique? I normally use a stainless wire brush I bought for aluminum only (i.e. it doesn't get used for other stuff), but I've seen other suggest things like scotchbrite pads, acetone, "chemical cleaner" (don't know what that is specifically)
any info would be helpful.
oh yeah, I only stuffed the electrode into the work once, and I was well aware of that boo-boo, so I swapped in a fresh electrode and still had what looked like a dog's breakfast!
Turn the machine on to dc +, then only using the Tig Torch press pedal. Look at the tungsten while you do this. Make sure you get a lil ball at the end of the tungsten. This doesnt take much when you do this. Then switch machine back to Ac to weld your aluminum. This should help let me know if your having problems.
Turn your gas up to 30 CFH. Make the tungsten stickout only 1/8 from the end of the "Pink" gas cup. Turn up the power until you can get a good molten puddle without shooting a ball of tungsten into the puddle. The black around the welded area sounds like perosity from lack of gas flow, or from the tungsten being very contaminated. Hope this helps!!
30cfh (I guess I was being cheap at only 12cfh!!!) - heh, the "pink" comment was only because I can't remember what the material is called, but I remember it is the "pink" kind
The tungstens were balled properly
I will go and attack it again and see what the heck I can get this thing to do with 30cfh of sheild gas flow.
Thanks for all the tips, and keep 'em coming
By the way, what is "chemical cleaner"?!?
All of that "chemical" stuff is really overated for the home shop welder. A SS wire brush will work for 90% of the oxides on the surface. From there, the AC wave balance can also help. Keep trying!!!!!
Sorry, I was not trying to dig you for the "Pink" cup, just messing around a bit. It is made from a ceramic material. Good Luck!!
I switched to my #9 torch (brand new in box) without a gas lens, and with about a #6 cup (guesstimating), and turned the argon up to 30cfh. I still got the black bubbly flecks & crap apperance, except for one area and one portion of arc which I was conscious of as it was happening...
I felt like the puddle was getting away from me, so I backed off on the pedal a little bit for a second or so, and the arc seemed to smooth out, and I could see things working a lot better. After I finished the little section I was working on, I flipped up the mask and found the mentioned section was shiny, didn't have any of the black speckles in it, and it looked reasonable (except for my filler control was still a bit wonky)
So this brings me to my next question... is it possible to overheat the metal? I was under the impression that oxide and alloy components would float to the surface and that was that - you have a moltent pool under the scum-skin... ideas?!?
(of course, the deal may have been me not pulling the filler out of the gas shield because it just dawned on me as someone else mentioned, I might be pulling the filler right out of the Argon cloud...)
ahhhhhhhh... I suppose if it was easy, everyone would be doing it, and I wouldn't have all these beginner questions
Set your balence control at 5, Don't worry about balling your electrode, it can be pointed or hemispherical for what your trying to do. The important part is that the electrode is perfectly clean. If there is even the smallest dip into the puddle or if the wire barely touches your electrode you must stop!
Any contamination on your electrode will cause black smut (which by the way is burnt magnesium). Aluminum has a tendancy to climb up your electrode so make sure its all off before you continue. The constant cleaning is a real pain when you are in the beginning stages but will pay off immedatly in quality. 30 cfh is too high stay between 15 and 25. Keep your electrode extention limited to the dia. of your cup oriface.
Get a low chair so you can keep your electrode at 90 degrees to the work, a bad torch angle can draw air into the puddle and is a common error with beginners.
Safety tip....Clean the alum off your electrode with a belt sander. Never dress alum contaminated on a stone wheel.
Let us know how you progress
I agree with Lawrence keep your gas around 20 cfh, 30 can tend to draw air into your puddle.4043 is the best rod to use on 6061 it could be your rod thats contaminating your weld.Also check your gas lense make sure there is no trash in it restricting gas flow.
I agree that 30cfh can draw air in with some turburlance, but he did state that he was using a gas lense which should eliminate this problem. Also, one of the most frequent problems we see with first timers is they tend to be very inconsistant with their arc length ie. from too close to too far away and back again. As your experience gets better, 20 cfh would work fine I'm sure, but 30 will allow for this change in arc length without the intorduction of atmosphere.
You ask if it was possible to over heat the metal. Yes.
Aluminum is a very efficient heat sink and often times can carry your heat away as fast as you can put in with you torch. But as you know has a low melting temp. If you try to put it enough heat in one spot to make a puddle often times you will melt through and draw in contaminants.
Have you tried preheating your work? Aluminum welds beautifully when every thing is at the right temp. By every thing I mean both pieces to be joined. Welding a thin piece to a thicker piece almost always requires preheating the thicker piece before welding.
I thought I'd reply to my first post because all the other posts are getting too thin, and it feels like they are disappearing into the screen!!!
There's been some interesting mentions of drawing contamination in from the backside, vernturi draw of atmospheric air into the shelding cloud, and arc length variations...
I can see the higher 30cfh flow exaggerating the potential venturin problem as opposed to say 15cfh, but will a gas lens work better than a standard gas nub/tip, or am I just pissing in the wind either way if this is happening? How can I prevent venturi draw in the first place? Is it something to worry about?
If all variables were stabilized (you know, one of those "text book situations"), what effect would varying the arc length have for a TIG arc? I would guess arc length variations are more pronounced with Helium than Argon, but still, what would I actually see happen, or better yet, what should I look for, and how much arc length should I try to maintain?
I agree that I could possibly draw crap in from the backside because until the tube/flange joint is completely fused there is a small opening, but is this the likely source of contaminants, or is it more likely that I'm jerking the filler rod out of the gas cloud when it's still hot, then jamming it back into the cloud a split second later?
Preheating, yeah... I have to been meaning to stick the whole thing into my bar-b-que, put it on high, then go sweep up the shop for a half an hour. I figure that about as good a preheater as I have around here, and I totally agree about it helping the job work properly.
You seem to be getting alot of feedback here so...I might as well join in with my 2 cents worth... If you are using a gas lense, then use 25 cfh of argon on the torch. Plus or minus 5 cfh should not matter and if you are paying for the gas...less is better. Whether you zirtungsten or pure doesn't really matter nor whether you switch to DCRP to get a ball on the tip, because you will anyway.....when you sre using AC/High-Freq-continuous. Welding 1/2" plate to sched 40 pipe is not hard, but you need plenty of heat so you should be using 1/8" tungsten and 175 amps with a rheostat.....aim the heat on the thicker of the peices to be joined, stick-out the electrode 3/8"-7/16" to do a fillet weld....mash the pedal until you see the puddle start to form (on the 1/2" plate) pretty much where the pipe meets the plate. The cool thing about tig welding aluminum is that you can use a relatively long arc length which is really the KEY as someone already stated.....the rod really likes to jump on the electrode. Anyway, once the puddle forms on the 1/2" plate move the electrode so both plate & pipe are getting the heat and then start adding wire a drop at a time (keeping the rod in the gas shield & off the tungsten!) and progress right to left(if you are a righty) one drop of metal at a time. Try and get a rhythem and go until you are no longer steady, or the rod is too short or (heaven forbid) you contaminated the electrode.
If you are like me, who drinks far too much coffee and keeping a steady hand is an issue then you can "cheat" by allowing the cup (made of ceramic by the way) to rest on the work, however, you cannot keep ANY pressure on the torch or you will not be able to slide the torch along the path of the joint and ofcourse it will be all up to you to keep the tugsten aimed at the joint.
Cleaning is important so I concur with what was mention by others. It the material anodized??? you'll get black on the weld with that for sure unless you deal with that.
When I first started welding(80's) my first job was tig welding aluminum at a plant which manufactures aluminum oil delivery tanks where cosmetic welds were mandatory. My department supplied the fenders, meter pans and ladders(using 1"-sched-40 pipe) and your 6061-T6 material....some of it was anodized, some wasn't. 4041 makes a shinier bead, but 5356 is stronger. I worked there for 3 years production welding until I got "burned-out" by doing the same thing over and over, but I really enjoyed welding aluminum. For what it's worth......the weld metal deposited (by ANY process) is 1/2 as strong as the base material when it is Aluminum.
Weld-on!
Here is an animation of the technique I use when GTAW-AC welding Aluminum that may be of use. The rocking technique allows me to see a little better whats going on and keeps the filler metal from balling up from the heat of the arc.
http://www.weldinginspectionsvcs.com/misc/GTAWAlumAnimation.htm
As mentioned by others, you may be pulling debris from inside the tubes or even the cut end of the tube. Wire brushing right before welding seems to help and be aware of any drafts from other sources.
Helium if used will require higher flow rates than will argon for welding flat and seems to be a little more "sooty" ?.
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