Control Warpage on Aluminum (from old board)
Registered User
Posts: 152
(7/14/04 10:35 pm)
Control warpage on aluminum
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This applies to both MIG and TIG on aluminum sheet.
Worst case scenario is welding a filler tube or doubler plate for fuel level sender right smack dab in the middle of a 24x36x6 un-baffled fuel cell (for example)
Your best bet is gonna be to tack the livin' ***** out of it BEFORE you bend the wrapper. This lets you use your welding table as a big ass heat sink, and/or something to clamp to.
On something like that, I usually tack in 4 places, let it cool, then 4 more tacks. Sometimes more, sometimes less.
Your weld sequence will also vary depending on placement of the part to be welded and thickness of the base material.
This is a pretty hard question to answer in depth due to the huge number of different scenarios you can come across. The three biggest points to remember:
Tacks are your friends.
It's gonna warp. How bad is up to you.
Patience!!
Matt
www.RFRCustomFab.com
RFR
Registered User
Posts: 153
(7/14/04 10:40 pm)
Re: Control warpage on aluminum
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By the way, starts and stops are no more important in this case than on any other AC TIG situation......Vitally important!
Matt
www.RFRCustomFab.com
zbugger
Registered User
Posts: 1570
(7/15/04 12:03 am)
Re: Control warpage on aluminum
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Matt, all great info. Now I just need to learn how to actually weld. With a welder. For real. Like in real life. Would a welder help me any? Would skill help? Ahh.... Nevermind....
- Allen
RFR
Registered User
Posts: 154
(7/15/04 10:46 am)
Re: Control warpage on aluminum
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Allen, you could use bubblegum (pre chewed, ofcourse) and do better than a bunch of the guys at my day job.
So, yes, skill would help, but apparently isn't necessary.
Matt
www.RFRCustomFab.com
parsonsj
Registered User
Posts: 1678
(7/15/04 12:33 pm)
Re: Control warpage on aluminum
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Matt,
I'm just talking about TIG welding aluminum sheet.
I ordinarily use .060 or .090 5052 alloy for fuel tanks and such. When I'm getting a nice bead going I really hate to stop since that means I have to get the bead going again. Plus the transition to the new weld bead is a prime spot for pinholes. On the other hand small short beads are what keeps the sheet from warping. I ordinarily tack weld so that the tacks are no more than 1 or 1.5" apart. I'm usually pretty happy with weld appearance (no worries about weld accuracy) until I get something like a Ron Davis radiator in the mail and see just how pretty those welds are. And I can't see any stops and starts. So how do they do that?
Any thoughts or advice?
John Parsons
RFR
Registered User
Posts: 155
(7/16/04 11:28 am)
Re: Control warpage on aluminum
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So I assume your question is about welding wrappers together? (Outside corners)
If that's the case, I don't know how to help you. You tack 1 1/2" apart...I tack probably 3" apart and have no problems on .100" 3003 H-14. I will run welds as long as I want, and still no problems. (And I run much hotter than you do) Only thing I can guess is that you're moving too slow.
Regarding getting pinholes...You've got something going wrong!
Will you please tell mw what machine you're using, what settings you're on and technique you use to clean your material? Also, filler size and alloy, tungsten size, alloy and point prep. Gas flow, gas lens or regular collet body, amount of tungsten extension, etc, etc.
Matt
www.RFRCustomFab.com
parsonsj
Registered User
Posts: 1681
(7/16/04 2:53 pm)
Re: Control warpage on aluminum
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Outside corners and sheetmetal to square tube.
OK, here is how/what/why
Lincoln 175 Square Wave Pro.
Miller Diamondback water-cooled torch (20M). I do nothing to prep the tungsten (I use pure tungsten for Al), other than to periodicallly break it off and square it up as it gets "used up". I let the welding form the ball end. I have the tungsten out between 1/8 and 1/4 inch. I've tried welding with both 1/16 and 3/32 tungsten diameters.
I use Lincoln's TIG Manual Welding Guide for settings. For .090 it recommends around 100A, 15 CFH flow. For .060 it recommends 60A, 15 CFH flow. Pure Argon.
I prep with sanding, washing in soapy water, rinse and dry. I use Aluminum-dedicated SS brushes to clean the material as I go (like between a stop and start on the same bead).
For filler material I use Lincoln's recommended alloy (can't remember it right now). For .060 I use 1/16 stuff, for .090 I often use 3/32.
I try to hold the torch at a slight angle and I work it from left to right when ever possible (I'm left-handed).
thanks!
jp
RFR
Registered User
Posts: 158
(7/16/04 3:46 pm)
Re: Control warpage on aluminum
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Does your machine let you adjust balance? If so, what are your settings?
Try this for me...next time you weld some aluminum, throw in a 2% thoriated tungsten (red stripe) that's ground to a point. Only difference is you need to grind a small flat on the end, otherwise you can get tungsten inclusions. (Not that that's a big deal for most stuff, it's just good practice.)
With any machine that has fixed balance & frequency, 2% tungstens won't last long, but you get a ton more control versus a balled pure tungsten. Arc starts are much much better too.
Extension is good.
Amperage seems alittle low to me. I've never followed the "1 amp per.001 mat'l thickness" rule...but everybody is different.
15cfh is good if you're using gas lenses. If you aren't (why not?!?!) you need to be around 20-22cfh, depending on cup size. I generally use a #7 cup size for stuff like this.
Have you leak checked your gas lines? If not, do it. Even pull the body off and check the line in the machine, as well as the selonoid.
I wonder if the water you're using to rinse with is screwing with you. I usually just wire brush and weld, but it all depends on the condition of the material. Stuff I've gotten back from the CNC machine shop, I wash in SuperClean, rinse with tap water and dry with compressed air.
Running hotter and slower will probably help too.
For arc starts, do you just mash the pedal, or do you ramp up slowly? If you mash-n-go, then you're probably not giving the arc enough time to clean the material.
Matt
www.RFRCustomFab.com
parsonsj
Registered User
Posts: 1682
(7/16/04 4:09 pm)
Re: Control warpage on aluminum
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Matt,
Good stuff! I'll give those suggestions a try.
My machine does not have balance control. It's Lincoln's so-called "optimized balance". Whatever that means.
I can try hotter and slower. I usually try to go fast to minimize heat input to the surrounding material.
Gas lenses, huh? (I've been using a #7 ceramic cup) I'll talk to my dealer about them. I assume I can use them on my Miller torch. Got a link to some documentation about 'em?
I think you may be on to something about the arc starts. I think I mash the pedal to start the arc, then back off, then run the bead. I'll try a slower start to the bead to help clean better. That could very well be the cause of pinhole leaks.
thanks again!!!
jp
RFR
Registered User
Posts: 160
(7/16/04 4:33 pm)
Re: Control warpage on aluminum
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I don't endorse this product (never used it), but the picture shows the difference between a standard collet body and a gas lens, flow wise. This is why 15cfh is ok when using gas lenses, but too low when using standard collet bodies.
Besides, gas lenses are CHEAP! The most I've paid for one was like 2 bucks. (new)
Matt
www.RFRCustomFab.com
parsonsj
Registered User
Posts: 1684
(7/16/04 8:34 pm)
Gas lens
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Now I remember. My Lincoln welder came with a gas lens torch, but was only rated for 125A and was air-cooled. Meaning it was as hot as hell when welding thicker aluminum. So I stepped up to the Miller water-cooled torch and it was not a gas lens. I meant to switch over later (kinda ran out of money then), but forgot all about it. I just ordered the parts to upgrade to gas lens.
jp
Curtis Menard
Posts: 3
(7/19/04 11:22 am)
RE: Aluminum
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I recently purchased a Miller 180SD welder and have been trying to teach myself how to weld aluminum. I have the hang of steel but I'm having issues with aluminum.
I've been practicing on .060 sheets building boxes. What I've been using is 1/16 2% tungstens with a balled end. If I were to try using a point should I step up to a 3/32 tungsten?
Plus I find myself pumping the pedal allot more on aluminum than steels. Am I doing something wrong?
parsonsj
Registered User
Posts: 1707
(7/23/04 3:29 pm)
Gas lens stuff is here
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I just switched over to gas lens. Now I need to weld something ...
jp
parsonsj
Registered User
Posts: 1738
(7/27/04 5:22 pm)
Holy ***** !!
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The gas lens makes a noticable difference. The weld looks smoother and cleaner. What an improvement!
I need to weld up some sheetmetal and see how that goes.
Thanks for the help.
jp
RFR
Registered User
Posts: 178
(7/27/04 10:10 pm)
Re: Holy ***** !!
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Matt
www.RFRCustomFab.com
loelco
Unregistered User
(8/9/04 11:01 am)
Thanks!
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I'm a machinist/fabricator for a living, but I've never needed to TIG and want to learn. Thanks for the tips, hope I get to use them someday! I learn a hell of a lot just being near you guys.
RFR
Local user
Posts: 215
(8/9/04 11:20 am)
Re: Thanks!
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Thanks Loel. Let us know when you get ahold of a TIG and we'll see if we can get you up and running.
Take it easy.
Matt
www.RFRCustomFab.com
yody
Registered User
Posts: 359
(8/9/04 11:40 pm)
Re: Thanks!
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where could i get ahold of a cheap used tig machine in CA, would love to learn how!
firebird website
RFR
Local user
Posts: 221
(8/9/04 11:45 pm)
Re: Thanks!
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Damn! I just sold my old one. Wasn't cheap though.
Your friendly local welding supply store should be able to lead you in the right direction. Other than that, Ebay (yuck)
And, remember, if you want to run aluminum, your TIG needs AC capability.
Matt
www.RFRCustomFab.com
Edited by: RFR at: 8/9/04 11:46 pm
Jensen
Posts: 8
(8/12/04 6:34 am)
picking RFR's brain
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Guess I'll jump in...
I'm running a syncrowave300. (Yody; got it off Ebay for $600) When welding Al I try to set the AC balance as high (more EN) as I can while still getting enough cleaning. The highest I can set it seens to be around 30%. At that setting I get atleast a 1/8 inch margin of oxidation around the weld. Examples of Al welds on your site show much less oxidation. Besides becoming a better welder, do you have any tips to reduse the oxidation and get more focused AC cleaning?
Looking at a 64 Chevelle this weekend. Then the questions will really start flying. Thanks,J
RFR
Local user
Posts: 231
(8/12/04 10:21 am)
Re: picking RFR's brain
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Terminology: White zones on either side of weld are etched . If they were oxidized, you would NOT be happy!
Either you're saying 30% when you mean 70% EN, or there's something wrong. To give you a ballpark, the 180SD's with fixed balance are set at (or close to) 65% EN. I NEVER run below 65%.
Those early transformer machines are funny. I used a syncrowave 250 for awhile, and a 50% change in balance netted me what a 5% change does on my new Dynasty 300DX! I wouldn't put too much faith into what the dial actually sais...just adjust for the best setting.
What tungsten are you using? What alloy and thickness mat'l are you working with?
Matt
www.RFRCustomFab.com
