[BigD]

Yes it's another thin aluminum thread

I haven't been able to find many threads specific to my concerns so I figured I'd make a special one just for me.

I'm still a beginner but I've got about a year under the belt and I generally have no issues with aluminum but thin stuff is the bane of my existence. My machine can do anything settings wise and I've tried all kinds of things and just as I'm feeling like I found the secret recipe, the toilet gets flushed.

Specifically, I'm trying to build a rounded box out of 040 sheet so it's all outside corner, and I'm practicing on coupon scraps and I'm nowhere near ready to work on the real piece. I can seem to get tack welds ok with the trick to jam the heat in there quick and tight. And if I can get going, I suddenly look like I know what I'm doing. But whether or not the get going part is successful, seems to be a coin flip.

I've tried 100-400hz, 60/30/10 pulse, 30/30/30 pulse, each one has done good and bad things that I was able to work around no problem... if I could get a pudde going. But once I see those edges get shiny, I hold my breath. Sometimes they join and I can keep rocking, other times they blow apart and I'm sunk. Earlier on with inside corners I used to have a problem with not enough heat soon enough but I've tried sneaking up on these joints and so far not much luck with consistency.

I know that seat time cures all but in the mean time, I would be greatful for any tips in your personal arsenal. For instance, how much washing do you do of the molten edges to try to get them to join and flow? One issue I think I have is if the arc starts jumping edge to edge, I overheat one face too much before the other side is ready and it blows back. Sometimes in a panic I try to jam filler in to save it but the filler just blobs, I get pissed off and things only get worse

[exnailpounder]

We all feel your pain. .040 is awfully thin so you're kinda asking for it Outside corners are the easiest IMO but I am just speculating that AL that thin is going to give you problems no matter how much time you have spent in the chair. Thin ANYTHING is more challenging than thick but I'm sure you know that. I bet you have the skills to do what you are trying to do but your patience is frazzled. I saw a video of Jodys about welding thin aluminum and I think he kicked the Hertz way up to get the puddle to stand up and behave. Sorry I couldn't be of more help but I just came in for a stiff drink after getting my ass kicked on thick to thin stainless and saw your post. Your gonna have these kind of days

[LtBadd]

Hey BigD
Ex is right, thin AL is going to present some challenges, which means all the preparations you'd normally do to weld AL is even more important, think clean and clean again the base material, little to no gap in the fitup, good torch angle...when you start a tack have the filler right there, as soon as you have an arc move it onto the filler as you increase the amps at the same time and melt the filler into the joint.

What machine are you using?

[BigD]

Thanks guys! Richard I'll give that technique a shot. I'll also own up to the fact that I'm not taking cleaning particularly seriously with the pieces being throwaways. I zip them through the bandsaw to make coupons and go weld them, no brushing or anything.

The machine is a Dynasty 210DX. What size tungsten would you recommend? I use 2% lanth. I started with 1/16, tried 040, back to 1/16 and now trying 3/32. I found when doing pulse, I had to turn up the amps to the point where with too much cleaning the thinner electrodes weren't holding their point.

Also, do you think getting some mig wire would help? The thinnest rod I have is 1/16, maybe I should get a small spool of 040 or something mig 4043? I found that made it much easier to weld razor blades by using some 030 mig wire - I could start the filler going once the base metal started melting. With the 1/16 rod I think part of the problem is when I try to use filler, the edges are already melting but it's too cold for the filler and it just sags. But I haven't tried what you're saying, I just keep the arc on the base metal and try dabbing the rod in there.

[MosquitoMoto]

I do heaps of thin aluminium because motorcycle fuel tanks are what I need to make.

Been working on this myself for about a year and yes, it takes some doing. I use a sharp 1.6mm, 2 percent Lanth electrode with a gas lens...I find the gas lens helps a lot, especially on outside corners. I even go to the trouble of building little dams out of aluminium foil sometimes so that the argon doesn't just fall away.

I did a lot of experimenting with pulse and I find that even 2-3 amps one way or the other can make an appreciable difference. There is a lot of 'fine tuning' to be done when you are working with thin aluminium.

Where there are no curves I always clamp/prop my sheets against a chunky aluminium chill block - this makes an enormous difference. The other thing I have noticed is that when you are working on small pieces of scrap and then graduate to big sheets, your amp settings go out the window because the bigger workpiece acts as a more effective heat sink.

And as others have said, clean, clean, clean, and go for perfect fit up. Sheet cut with a bandsaw welds nowhere near as well as sheet that I cut with my aluminium mitre saw blade.

I feel for you - this is my white whale, too. But persist. I think maybe the best advice I can give is to get out there as often as possible and take notes on everything you do.



Kym

[LtBadd]

Thanks guys! Richard I'll give that technique a shot. I'll also own up to the fact that I'm not taking cleaning particularly seriously with the pieces being throwaways. I zip them through the bandsaw to make coupons and go weld them, no brushing or anything.

If the practice pieces aren't prepped the same as the production pieces then your settings will be different, the practice coupons need to simulate real life as close as possible.

The machine is a Dynasty 210DX. What size tungsten would you recommend? I use 2% lanth. I started with 1/16, tried 040, back to 1/16 and now trying 3/32. I found when doing pulse, I had to turn up the amps to the point where with too much cleaning the thinner electrodes weren't holding their point.

1/16" should work, try using triangular wave forum, its for thin materials. Adding pulse may not be helpful if you're not familiar with this, and only introduce more settings to play with, keep it simple unless you feel comfortable doing so.

Also, do you think getting some mig wire would help? The thinnest rod I have is 1/16, maybe I should get a small spool of 040 or something mig 4043?.

For Aluminum I wouldn't go smaller then 1/16, you will need to add filler fast to keep the puddle full, it's a different animal then any other material.

Kym has good ideas from his experience, are you able to use heat sinks?

[kiwi2wheels]

Try using a standard #5 ceramic on some coupons. You might find it works.

Can you fold a flange on one panel and give yourself a lap style joint you could clamp with clecos?

[Oscar]

0.040", eh? Lets see a pic of your tungsten point. Just how good is your fitup? Are you able to tack successfully and consistently? Lastly, show a pic of your actual arc length without actually firing up.

[Harry72]

Have you tried pulsing just using the pedal, I repaired some cheap Chinese under tray boxes for my ute(about 1.2mm thick chequer plate)like LtBadd said jam the filler in and bring the arc up on it and give the pedal a stab to melt it in, back off and move about a mm or two(keeping on the downhill of the last bead) and repeat.

[BigD]

Thanks again guys!

I'll try to use a chill block but because this is basically a quarter circle shaped box, that will be hard to do on the real thing.

The fitup with the bandsaw is pretty good, especially for coupons since I'm joining the complementary cuts together But I'll do my best to make it zero gap.

You're all right, I'll clean up my next practice session like the real thing.

I forgot to mention that I was using triangle wave. Seems to work quite well, I tried using the pulse and sometimes it made things easier but the bead seems to sit on top of things too much, which is a great demo of its usability for building up on thin material but I don't think it's needed here.

The trick about putting the arc on the filler might be my missing ingredient here. I'd never heard/thought of that. I've programmed myself that the rod only goes into the puddle, so you must have one going first. The only exceptions I've allowed for myself was when I was welding the upright posts of my rollcage to the upright face of a base plate, then I got a thick rod into the V and walked the cup up.

Kiwi, yeah I heard that too that a regular cup works better for some guys on thin alu for some reason. I'll add it to the list of things to try. The flange would be hard since most of the welding is on a constant curve but not impossible. But part of the reason I'm doing this instead of buying one of these things is the challenge to do it the hard way. Well, I guess if I really wanted the hard way I'd weld it from the inside but I want hard, not mad.

Oscar, no pics handy but I seem to have no trouble with tacks most of the time. I try to have overlap and then melt the overlapping edge down onto the butting one.

Harry, yeah I'll try that idea like Richard said, I've never done that before. I'm used to filler only being introduced after the puddle forms and even then it only goes in the puddle.

Dmitry

[BigD]

Here's today's disaster. At least I have pics this time. No problem with tacks again, much better with the beads but still sucks. I think this time it's just my exhaustion I was propping my body on my torch elbow, getting out of position and not stopping. But overall it was ok. But when I tried to start on the far tack it still melted away on me.

I turned the frequency down from 400 to 120 and I seemed to have better control, maybe the 400 is too focussed? Or maybe I'm just not used to the assault on the ears of the 400...

One thing that was a complete fail was the idea of moving the arc to the rod and melting it in. The moment I would do that, it would just ball up and blob, every time.

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[kiwi2wheels]

Depending on size, if your box is a quarter round, make a hammer form out of masonite or plywood. You can do L and R ends and it makes jigging a breeze with clecos.

[BigD]

Not sure I follow, I've never used clecos but I'm familiar with the idea - they are temporary placeholders for rivets. I don't want any holes in the box.

Can you guys elaborate on the arc to the filler rod technique? What could I be doing wrong? I hold it as close as I can without having it melt, then I move the torch onto it and it just softens and balls up instead of melting down into the joint (other times I have touchdown).

[exnailpounder]

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BigD...the thinnest aluminum I had was .060 ( your metal looks thicker than .040 but it might be the pics)you can see in this pic where I tried using filler, 1/16" 4043 and it was it didn't go well and then I just decided to fusion weld. I got the puddle started and just kind of went back and forth a little to get it nice. The flash washes out the detail but the weld actually looks good except the first inch where I was trying to dab in filler so maybe scrap the filler metal and just fuse the corners. Miller Syncrowave 210, 75 amps, 75% cleaning, 1/16" E3 tungsten, gas lens setup, 15 cfh. The 1" angles are clamped to the aluminum to trap argon. It welded very easily. You must trap your gas on an OS corner or you will have trouble with your weld. This metal was from my scrap pile and was very dirty so I spent time getting it really clean which is very important! Hope this helps

[kiwi2wheels]

Not sure I follow, I've never used clecos but I'm familiar with the idea - they are temporary placeholders for rivets. I don't want any holes in the box.

Can you guys elaborate on the arc to the filler rod technique? What could I be doing wrong? I hold it as close as I can without having it melt, then I move the torch onto it and it just softens and balls up instead of melting down into the joint (other times I have touchdown).

You use 3/32" clecos with the holes centered 1/8 " from the sheet edge. You'll fill them with the weld bead.

[Turbo]

I tried this when I first bought a tig welder just to practice. I was using the "aluminum" from the steel rack at Lowe's or somewhere like that. I think that stuff is for under your house siding around your windows and I have no idea what alloy it is. Some aluminum alloys like to just collapse into a blop right before your about to add filler. If that's what you are using I would suggest you buy a sheet of something that you know what it is and that it's easily weldable.

I would recommend against buying mig filler just for tig welding. You will have to twist 2 strands together if you want to make a straight rod. I think you'll be ok with 1/16th.

If you get a big swirling black blob that means you need to back up the joint. I use pieces of 2.5mm aluminum sheet that I bent on the brake and tape it into the backside of the joint using foil tape.

[geo]

When repairing thin aluminum like a tear where you can't get a backing on it I like to tack and tack (no filler just a stab) focusing on fit up and working with the heat. If I blow a tack I lay in some .040 rod to touch both sides and file down the high spot when done. Important part of the tacking period is to make the shape correct.
When the tacks are about an inch apart I stitch weld starting at a tack and going through the next then move away to an area that is easy to put a hand on (not hot). If your stop shows a hot crack shorten you bead by adding more tacks. Some times you just need to give it a break to cool.
You need so little amps on thin stuff even 5 amps too much will weaken the alloy enough to slump (lose the fit-up thus the hole) so short welds make it easier for us mortals.

Boxes and symetrical structure? A shelf of different sized blocks and plates is your friend. Begin your collection soon.

[exnailpounder]

I tried this when I first bought a tig welder just to practice. I was using the "aluminum" from the steel rack at Lowe's or somewhere like that. I think that stuff is for under your house siding around your windows and I have no idea what alloy it is. Some aluminum alloys like to just collapse into a blop right before your about to add filler. If that's what you are using I would suggest you buy a sheet of something that you know what it is and that it's easily weldable.

I would recommend against buying mig filler just for tig welding. You will have to twist 2 strands together if you want to make a straight rod. I think you'll be ok with 1/16th.

If you get a big swirling black blob that means you need to back up the joint. I use pieces of 2.5mm aluminum sheet that I bent on the brake and tape it into the backside of the joint using foil tape.

I think that home centers sell 1000 series aluminum. It's soft and welds like crap. I used to practice with it until I bought some 6061 at the metal supply and what a difference in weldability. I will respectfully disagree with you about the Mig wire. I tried using 1/16" on that .060 in my thread up there^^ and it was like trying to use a tree trunk on that thin metal edge.

[BigD]

Thanks for the input guys, it's around 040, I measured one edge in the pic but it also had a little saw flashing. I definitely need to stock up on scrap blocks for propping and chill blocks but it's hard to justify on the spot in the metal store, esp aluminum is so expensive nowadays.

Today's practice session was a rare experience where it's a coal that turns into a diamond (ok maybe just some dirty carbide but still positive). I started out not even being able to tack anymore, I was about to pack it in thinking my head is not right tonight if I'm screwing up such basics. But I decided to ruin a few more coupons and things slowly got better. I tried some butt and lap joints and realized for some reason, on the outside joints the torch angle I'm holding is way too steep. They always tell newbies that your torch should be almost vertical but that just doesn't work for this joint for me.

I tilted it back a bit and I was able to wash the puddle forward and rock and roll. I still melted out some tacks at the ends but built them back up with the pulser. Managed two coupons in a row and took that as a sign that I'm done for today, before I start regressing again.

I'm now more confident that I can get my project done, maybe not as pretty as I'd like but it'll hold water. I'll keep practicing

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Practice makes... modern art masterpiece?

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[BigD]

Well alright then... I'll call this a success. Played with the Dynasty pulser again and found my elixir. 150 pulses, 30% on 8% background (wanted to try less than 10 but not 5 lol). When tacking I realized I have so much heat control that I can run the damn tack all the way down and that's what I did. Then turned the pulser off and ran a bead over it. Other than some hearsoak towards the end I was a bit slow to react to, I am thrilled!

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[jumpinjackflash]

OK Here goes as a report of what worked for me and the material I had- .030" 6061 T-6 sheet.
Machine Dynasty 210 1/16" 4043 filler is the smallest I have
18CFH 100% argon running a 17 watercooled CK torch w/gas lens-pulse set to 60 pps,33% peak, Backgnd 33%.
Amps set to 70 w 70% balance @ 400Hz
I did have my 1/2" copper plate to back the corners up..lit up on it to wash onto the corner

[BigD]

Thanks J.J., sounds like I'm on the right track! Have you tried higher PPS? I tried 150 after listening to a tips and tricks podcast episode where they said higher pps pulsing really helps contain the arc. Working like a charm for me.

You guys with your chill blocks... I need to stop being a cheap bastard and raid my metal store's copper offcut bin with some cash and a smile...

Another practice coupon today. Feeling good about doing the real thing, maybe one or two more practice sessions. This one went pretty much exactly how I wanted except a little chewed out edge from the tack at the far corner.

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[jumpinjackflash]

As for the copper... I have a good friend that pulled some 480v change gear out of a building in town. This was the main power interrupt. He was able to keep all of the pieces. I have 1/2 and 5/8 thick plates bigger than your hand. Also have some 1.25 x 2 aluminum that machines really nice... hardness test shows to be near a 7000 series? Weird for electrical service or the current passing through it could have changed it... who knows. I didn't care as it was all free. Even have some 1/2 -13 copper bolts-nuts-lock washers.

[BigD]

Success on the first attempt again. Picked up a block of offcut aluminum and copper, made the difference for getting the very ends to fuse without chewing back. Still far from perfect but I feel confident I can get my project done.

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[Oscar]

Well alright then... I'll call this a success. Played with the Dynasty pulser again and found my elixir. 150 pulses, 30% on 8% background (wanted to try less than 10 but not 5 lol). When tacking I realized I have so much heat control that I can run the damn tack all the way down and that's what I did. Then turned the pulser off and ran a bead over it. Other than some hearsoak towards the end I was a bit slow to react to, I am thrilled!

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That's a nice tight tack "bead"! I bet you're thrilled to have 400Hz AC Freq capability!