need help welding 6063 extrusion


Hello, all,
I got myself roped into a project making up frames for panels to
protect stained glass windows when a church sanctuary is used for a
gym during the school week. We went and got $800 worth of 6063
rectangular extrusion from the metal yard, and I'm having an
incredibly tough time TIG welding this stuff.
I don't have a lot of material to spare while fooling around,
either, we bought them out of an odd size, 1 x 1 7/8 x 1/8" wall.
(That's 1 x 1.875" outside dimension.)
I just got in some 3/32 Zirconiated tungstens, a gas lens set for that
size, and some 3/64" 5356 MIG wire for filler. I got a pretty good
fit-up of the edges after a whole bunch of fooling around with my 4x6
hor-vert bandsaw. I tried to weld this with without grinding a vee to
fill, maybe that is part of the problem, although my TIG book suggests
that is possible up to 1/8". I have a Lincoln Square-Wave TIG 300 that
as far as I know is working perfectly. I have a Weld-Craft
water-cooled torch with a Miller cooler. I know that MIG wire is
not the perfect thing for TIG, but I'm not even sure I need filler wire.
Does anyone have any advice on what to do, common newbie pitfalls,
etc? Obviously I can't support the back of the weld inside the tube. I
think preheat is going to be needed, I have a Bernzomatic propane torch
and an Oxy-Propylene set (essentially generic Oxy-MAPP) but have no
idea how much pre-heat to use. I did try welding a couple pieces
of tiny scrap, and that went a LITTLE better, I did actually get fusion
along part of the seam. That sort of supports the idea it needs
preheat. I KNOW I'm in way over my head, here.
Thanks,
Jon
Reply to
Jon Elson
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When the pro's get here they are gonna want to know, among other things:
1) How many amps are you using? Aluminum requires lots of amps. (You should have 150 amps available, minimum). 2) AC? DC? Polarity? Aluminum likes AC for cleaning and penetration. 3) What techniques are you using to remove any anodize, surface oxidation and gunge? TIG needs clean, clean, clean for the workpiece, filler and tungsten. 4) What problems are you seeing? Cracks? Lack of fusion? Burn through? 5) Equipment -- do you have a color filter to allow you to see the puddle? 6) Are you welding in position or out of position? 7) Straight argon for shielding gas, right? What flowrate? 8) You are regulating current using a foot pedal, yes?
Have you reviewed Ernie Leimkuhler's excellent TIG FAQ?
--Winston
Reply to
Winston
Yup, that's about where I set the dial.
AC, and I've tried a variety of wave balance settings.
The metal is quite clean, but I didn't use solvents on it. I did brush with a stainless wire brush I use only for aluminum. I haven't been using much filler.
Much lack of fusion, the sides of the joint pull away (melt back) leaving a gap.
I have an auto-dark lens with variable darkness, and I can see the puddle pretty well.
Not clear what you mean, here. I have the seam laying flat horizontally. Due to the piece being 12 feet long, there are some limits, but I could set this up so the surfaces to be welded are vertical.
Straight Argon, and I've tried several settings. Usually I can get good welds at 5 CFH, but I have turned it up to 10 with no change. I am using a gas lens in the torch.
Yes.
Yes, but not recently. Maybe I should reread it.
Thanks,
Jon
Reply to
Jon Elson
(...)
You don't really see a weld 'pool' at all? I was cruising the web just now and noticed that the accepted practise is to add ~5 to 7 percent filler to join 6063 in order to prevent cracking. If there is no pool to dip your filler into, that is going to be a big show stopper.
We have now exceeded the limit of my tiny knowledge on the subject so I think you should speak with those that really do know.
Your best bet is to subscribe to sci.engr.joining.welding and ask the experts. I see that Ernie Leimkuhler was answering questions in that newsgroup as little as 4 hours ago. Ernie is who God asks.
You might want to compose your question so that the experts don't have to work unnecessarily.
Were I you, I would repeat the question you asked here but I would add the details that you mentioned just now, plus any details you can add that seem useful. Use of High Frequency and Pre-flow and post-flow settings for example:
"I'm attempting to TIG weld some 12' long box tube 6063 1 x 1-7/8 x 1/8" wall (1 x 1.875" outside dimension) using 3/64" dia 5356 Mig wire filler.
Just as I begin to weld, I see the edges of the joint pull away, forming a gap. I expected them to form a pool but they don't. What could be the issue here?
Tungsten: 3/32 Zirconiated Gas Lens: Yes. 5 CFH straight Argon. Tried 10 CFH with no change Filler: 3/64" 5356 MIG wire Prep: Stainless Steel brush used only for aluminum, No solvents, No Vee prep. Welder: Lincoln Square-Wave TIG 300 with foot pedal Torch: Weld-Craft water cooled with Miller cooler Position: Flat on the bench, horizontally Polarity: AC Squarewave. Tried different balance settings. Helmet: Autodark lens but no Anti Sodium flare lens High Freq: [You do have that turned on, right?]"
Best of luck and please keep us posted.
--Winston
Reply to
Winston
(I don't wanna put words in people's mouths, all evidence to the contrary notwithstanding.)
Yeah, I do stuff that "just works" and isn't printed anywhere, too. It's been many years since I've welded aluminum and had forgotten that characteristic.
--Winston
Reply to
Winston
1/8" wall 6063 should be easy peasy.
Your kit sounds quite sufficient. You should not need any preheat. Turning up the gas a bit to 20 cfh or so might help. If it doesn't you can always back off. You do need to be able to establish and control a puddle. Clean metal is essential.
With zirconiated tungsten (good choice), grind them sharp. They'll self-form at your current level. If/when you dunk the tung: break it off, regrind it and start over. Contaminated tungsten doesn't work well.
You do have your HF on continuous and the welder set to AC, right?
Once you get a puddle going, you might try 1/16" 4043 rod. It might wet a bit better for you.
Reply to
Don Foreman
It's been my experience that aluminum often will do this. I'm more of a 'just do what works' type and less of a follow the book welder, what I've always done is just stab the filler rod right smack in the middle of the two. Once you have the two sides joined in a common puddle, you're on your way. On thinner materials, I sometimes melt off a small blob of rod right on the joint, and melt it into the material as I bring the heat up.
Jon
Reply to
Jon Anderson
Haven't seen any postings by Ernie lately---where can I get a copy of the FAQ ?? Jerry
Reply to
Jerry Wass
likes AC for cleaning and
and gunge? =A0TIG needs clean, clean, clean for
Lack of fusion? Burn
a foot pedal, yes?
Jon, Don=92t know if this will help you, but maybe something here will strike the right chord:
Describes common problems in aluminum TIG welding:
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aluminum before welding:
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From CIGWELD. More for MIG welding aluminum, but discusses moisture problems:
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I=92ve read that it=92s better to use solvents/cleaners before wire brushing or sanding to prevent driving in surface contamination. Have you tried sanding disks or flap disks? Some people prefer these to wire brushes. I suspect that a cleaner surface may allow you to get your puddle wet sooner and avoid melting back the metal and use lower amperage. Have you had any success with tack welds or just running beads on the material?
Reply to
Denis G.
Jerry, I don=92t know if a FAQ actually exists. At one time, Mike Graham was going to write one for sci.engr.joining.welding, (SEJW) but it was a big undertaking and I believe that he lost interest in the group.
Ernie often hangs out at SEJW and you can learn a lot by reading the archives:
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here:
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his website with metalworking links:
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post on welding 6063:
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Reply to
Denis G.
(...)
I looked all over for it just now and wasn't successful. That's funny because Ernie used to paste a copy as a useful guide in many of his responses.
As Denis G mentioned, Ernie is available to answer specific questions:
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--Winston
Reply to
Winston
Hi Jon
3/64" is pretty small for filler at that gauge. Do you find the end of the filler rod dropping off before you have a puddle? For me, I would be using 3/32" lanthanated, 3/32" or 1/8" filler. As someone else mentioned, 4043 would wet a bit better. I'd probably set the current at about 150A (assuming you have a pedal), and the argon to at least 15 CFH. You will need filler wire, as most aluminum is 'hot short' and will likely crack if no filler is added to the weld.
Clean the weld zone with a wire brush (stainless of course) or Scotchbright or similar product. Clean with acetone. Do the same thing with your filler rod. Setup your parts, and make sure they're well grounded. Start the arc at about 1/2 pedal and work it back and forth over one inch or so, and watch the surface carefully. You should be able to see the aluminum oxide surface erode and expose the unoxidized aluminum beneath. When you do, give some pedal, and when the surface goes shiny and wet, add some filler. Be sure to keep the end of the filler rod in the argon cloud, and carry on laying bead once you've got it going.
Hope this helps!
Pete
Reply to
Pete Snell
This should be a very easy weld to make, as aluminum goes. First off, don't assume aluminum will behave like an easier material, like stainless. It won't fuse without adding filler, regardless of how tight you make the fit-up, and oxidizes in a flash if shielding is inadequate.
Crank up the shielding gas - 25 CFH is not too much, especially on an outside corner.
You'll be adding much more filler than you would for a similar joint in ferrous metals. 3/64 filler is much too small, get some 3/32 5356 or 4043 wire.
Again in comparison to SS, you can't just hit the pedal and start welding. You need to warm the area with the torch first. 1/8 material won't require much; the effect is more pronounced with heavier material. Play the torch on the joint at a relatively low heat. Keep the torch moving a bit and avoid the corner of the tube until you're ready to start adding filler. There are some visual cues to the right moment to start adding filler, but without a hands-on demo you'll have to experiment.
If you see anything more than a light gray oxidation near the edges of the bead, either clean more thoroughly or turn up the gas. A SS wire brush should be adequate for cleaning in a non-critical weld like this. You shouldn't need the solvent.
And most important, practice, practice. Laying down an aluminum bead is easy. The hard part is getting your set-up right and *starting* the bead. Post some photos of the problem joints if you're not making progress.
Reply to
Ned Simmons
Thanks for the hints. I dropped by the welding store and got a new stainless wire wheel and some 3/32" 4043 filler. I cleaned with acetone (did the wire wheel, too, as someone suggested). I ground a vee on the pieces to give me something to fill up, and it is working a LOT better. I still need some more practice runs, but I'm starting to see some success with the 6063 alloy.
Thanks again,
Jon
Reply to
Jon Elson
You Rock!
--Winston
Reply to
Winston
Well, I'm afraid that was a bit premature. When I get good enough to actually start on the rectangular tube, then maybe "I'll rock!" Right now, I'm still messing. I got a weld that looked real good on one side, but easily broke apart with bare hands. So, I got real poor (practically NO) penetration. I will make the Vee groove deeper, turn up the current a little, and try some more. I have made enough progress that I think I WILL get this, eventually.
Jon
Reply to
Jon Elson
Be sure to clean and degrease the filler rod.
Reply to
Jim Stewart
It's cool when you see the possibilities opening up.
Yup. Workpiece, filler and tungsten all must be clean and degreased.
--Winston
Reply to
Winston
You will.
Don't get too focussed on penetration. Focus on wetting. A weld happens when metal fuses to metal. Penetration is relevant if/when the puddle must have enough depth to create acceptable weld cross-section. Ally puddles tend to be shallow. Helium puddles are deeper than argon puddles. Joint design is highly relevant. With aluminum, wetting is usually the issue. You need to establish and maintain a puddle that wets the parts to be joined.
Reply to
Don Foreman
The actual project is a 12' by 3' frame made out of 1 x 1.875" 1/8" wall rectangular tube. So, it really does need some strength. One of the 12' vertical pieces will be attached to hinges, and the whole thing covered with an acoustic-absorbing wood material. It is supposed to keep basketballs from breaking the stained glass windows in the "closed" position, and be an acoustic treatment when "open". The thing is going to weigh something like 75 Lbs when complete, and obviously take some abuse in the gym mode.
If I can rip the welds apart with my bare hands, it won't work.
Well, I made a deeper groove and turned up the current, and I got something that looked HORRIBLE, but I couldn't break it, even with both hands and a knee. (These are small practice pieces, with a 4" seam on 1/8" material, welding from one side only, like I will have to do with the rect. tube. This 4" material appears to be harder to weld than the actual tube I will be doing, so I may be "good enough" to try the real material now. This practice stuff cracked VERY badly when I welded it without filler, but one piece of tube that I had some success with didn't crack at all and gave a very good looking weld where I got it to fuse. (I had a lot of trouble starting the weld and making ugly holes in it. I think I'm getting the hang of starting the fusion with filler and a V groove, now.)
Thanks,
Jon Jon
Reply to
Jon Elson

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