[nelson]

I butt welded some 1/4 inch and there's a hairline crack throughout.
160 amps no filler.
Is filler the only way to avoid this? On startup and when the work was over 300 degrees, same thing.
Any guesses as to the penetration? 6061
Thanks!

[Oscar]

Yup pretty much. Aluminum does not take well to autogenous welds.

[Toggatug]

What type of joint are you going for?

Usually alum doesn't like fusion welds in my experience they either crack right away or crack very shortly down the road.

1/4" material I would figure is not fusion weldable with any degree of strength.

Perhaps if I machine did it with 100% ideal conditions? But I'm just guessing at that


Also just re read your post. Amps seem low to me. I'd normally be running 250-280amps depending on joint type.

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[tweake]

i'm told that only 5 series can be autogenous welded.
but i don't like sunken welds so i always fill.

160 amps is really really cold. you need full penetration.

one thing i do not like from stainless guys is not doing full penetration welds. its really easy with stainless to whip around and autogenous weld without full pen. that does not work with aluminium.

[Spartan]

It's getting scary how many welders are defaulting to fusion passes these days regardless of material, joint type, or application. I guess it's just too easy to run pulse fusion passes to make a pretty weld. Pretty until it cracks that is...

But the welder will have gotten the pic of that pretty weld up on Instagram well before the joint cracks while in service, so it is likely of little import to them, unfortunately.

[cj737]

I run 200+ amps for 1/4” with 1/8 filler. That barely gets full penetration, even with a bevel.

With aluminum that thick butted-up, you can blast the seam and “keyhole” it then stuff filler in. That insures 100% penetration. Otherwise you’re guessing.

[Dimestack]

You definitely want to use wire for your tacks. It’s not like stainless or steel. Even if you get it fused and you start welding they will break very quickly as the piece grows. Aluminum like wire for tacking. Tack more often than you think you should on outside corners and be very picky on your fit up. Wipe it clean and I’d say use 4043 wire. If you use 5356 or “color match” for anodized parts that will have a greater tendency to crack. I’m these cases small stitch welds to hold it together before proceeding to the entire joint. It gets easier.

[nelson]

Thanks for the help!
I'll run some 4043 in. Stronger and no color match issue.
I've got 160 A max so I'm thinnin weld inside & out for integrity.

[Toggatug]

Preheat would help as well but it's never going to be quite right @160

Used to weld the same stuff I do now with a 185 amp machine. Now I have 400 at my disposal and I can tell you it definitely makes a difference and you won't know how much easier it can/should be with the right amps for the part.

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[tweake]

Thanks for the help!
I'll run some 4043 in. Stronger and no color match issue.
I've got 160 A max so I'm thinnin weld inside & out for integrity.

at 160 amp i think your dreaming a bit. rule of thumb is if you need to weld at 160 amps you buy a 180-200 amp welder.

you might get it with bevel and preheat. not sure without going and testing it if you would have enough for the 2nd pass.
keep the cup size small (4,5), the least amount of cleaning action you can (say 20% cleaning). pre heat it.

i think jody has video on a thick aluminium bit that he preheated.

[G-ManBart]

1/4" aluminum with only 160A is way, way outside the box...like double the thickness you should plan for with that size machine.

Pre-heat will obviously help, but I'd be looking to find a way to add helium to the setup as well. I've tried 1/4" aluminum with a 200A machine and it was possible, but far from ideal...can't imagine what it would be like with only 160A.

[Oscar]

1/4" aluminum with only 160A is way, way outside the box...like double the thickness you should plan for with that size machine.

Pre-heat will obviously help, but I'd be looking to find a way to add helium to the setup as well. I've tried 1/4" aluminum with a 200A machine and it was possible, but far from ideal...can't imagine what it would be like with only 160A.

My guess is the puddle was extremely wide and concave, further exacerbating the issue of hot-shortness.

[G-ManBart]

1/4" aluminum with only 160A is way, way outside the box...like double the thickness you should plan for with that size machine.

Pre-heat will obviously help, but I'd be looking to find a way to add helium to the setup as well. I've tried 1/4" aluminum with a 200A machine and it was possible, but far from ideal...can't imagine what it would be like with only 160A.

My guess is the puddle was extremely wide and concave, further exacerbating the issue of hot-shortness.

I don't doubt that at all...it would have to be. I'm tempted to set one of my machines at 160A and see how long it takes just to get a puddle started on 1/4" aluminum.

[cj737]

I don't doubt that at all...it would have to be. I'm tempted to set one of my machines at 160A and see how long it takes just to get a puddle started on 1/4" aluminum.

With a preheat and the correct settings, you can get it to puddle with 160. You WON'T get nearly the penetration desired in a single pass, butt joint though. Far from ideal amperage, but it is achievable. I certainly can see the amps dropping to 160 during the weld, but only long after the 200+ really needed is poured into the parts.

I welded up some 1/4" 6061 sheet to make a tool box for a tow trailer. I borrowed my buddy's Dynasty 280 for it (I have the 200). I ran a preheat with MAPP, 240 amps, 90Hz, 72% EP. I stuffed 1/8" wire in like it was on sale. And I did weld both sides for added strength. That project I used a 26 air-cooled torch and a 1/8" tungsten (pure as I recall). Worked great. Welds are very strong and plenty of penetration. I would bet that at times I was peddling down to near 160 amps to keep up with the heated material.

[G-ManBart]

I don't doubt that at all...it would have to be. I'm tempted to set one of my machines at 160A and see how long it takes just to get a puddle started on 1/4" aluminum.

With a preheat and the correct settings, you can get it to puddle with 160. You WON'T get nearly the penetration desired in a single pass, butt joint though. Far from ideal amperage, but it is achievable. I certainly can see the amps dropping to 160 during the weld, but only long after the 200+ really needed is poured into the parts.

That's why I said I would just be interested to see how long it would take to get a puddle at such a low amperage...not if it would happen at all.

Regardless, I wouldn't trust a weld done with that method. I just turn the dial to 250-275 and hope my feeding hand can keep up

[cj737]

Regardless, I wouldn't trust a weld done with that method. I just turn the dial to 250-275 and hope my feeding hand can keep up

Amen to that.

[Dimestack]

This is quickly becoming all about amps. While having the ability to use more is always nice, it’s not always an option. Consider the size of your work. Obviously the more surface area you have on a part the more heat you’re going to need to puddle in a timely manner. If heat is a concern I can’t say enough how helium will help you. It’s actually amazing what even 25% will do. Preheat is always a favored option, I find helium does enough on its own. If you have the ability to get that part elevated off your table and only using necessary clamps or fixture to hold the work then whatever your table size is won’t be robbing your heat while you get going. When the table gets hot you can go faster and faster. If it’s work just ask for a new machine! If you’re at home toss them in the oven if you can or use a torch for preheat. Whatever works

[Dimestack]

Nelson, I just saw your location. I’m just outside philly. Pm me if you wish.

[cj737]

This is quickly becoming all about amps. While having the ability to use more is always nice, it’s not always an option. Consider the size of your work. Obviously the more surface area you have on a part the more heat you’re going to need to puddle in a timely manner. If heat is a concern I can’t say enough how helium will help you. It’s actually amazing what even 25% will do. Preheat is always a favored option, I find helium does enough on its own. If you have the ability to get that part elevated off your table and only using necessary clamps or fixture to hold the work then whatever your table size is won’t be robbing your heat while you get going. When the table gets hot you can go faster and faster. If it’s work just ask for a new machine! If you’re at home toss them in the oven if you can or use a torch for preheat. Whatever works

It has become about amps because amperage is required to generate the penetration and weld ability of the material he is using. You can not weld 1/4” aluminum with 160 amps, even with a 50% He mix. You could with 100% He and DC, but that is not what he asked.

Even preheating the material won’t yield the results needed in lieu of sufficient amperage.

[Oscar]

This is quickly becoming all about amps.

Like cj737 said, with aluminum it is ALWAYS about amps when using a standard TIG approach with only Argon shielding gas (and assuming everything else is in order). You simply need a buttload of it at the beginning, especially with small parts, as they will readily conduct the heat and heat soak so fast, before you weld 1" of the seam, you end up with...



...because you forgot you need to out-run the heat transfer which is much faster than steel (~ 5x faster).

[Dimestack]

You might end up with that. I don’t. You can always get more out of your machine than you think. There is a difference between weldable metal with your machine and 100% penetration. Welding is a combination oh heat and speed. If you’re hot enough to sink in like that you need to pick up the pace and dump in that wire

[cj737]

You might end up with that. I don’t. You can always get more out of your machine than you think. There is a difference between weldable metal with your machine and 100% penetration. Welding is a combination oh heat and speed. If you’re hot enough to sink in like that you need to pick up the pace and dump in that wire

Oscar’s example is no filler. And I’ll wager $1,000,000 you didn’t weld that socket with 160 amps. Would you like my PayPal account to transfer the money over?

[Dimestack]

You know it’s not 160. The example is to show that you can weld thicker than you think with a few tricks to help. As I stated before you need wire on those tacks. The type of wire also plays a factor. I think we’re getting a bit out of control here. I say it can be welded as it yes it’s absolutely possible to weld. It won’t be quick, it won’t be easy but there are ways to help.

[nelson]

Thanks a lot guys. I can't do He, the company won't buy bigger machine for the odd large job.

I was basically trying to weld a large heat sink . A box 12 X 12 X 18 of 6061 for processing some rubber parts. A 1/2 hp motor with a 5 inch propeller go at the bottom. This said, this has to be strong.

I've welded a lot of thick Al with luck. Nobody got hurt, no machine broke.
If I do 2 passes with lots of filler the crack should go away?

[tweake]

Thanks a lot guys. I can't do He, the company won't buy bigger machine for the odd large job.

I was basically trying to weld a large heat sink . A box 12 X 12 X 18 of 6061 for processing some rubber parts. A 1/2 hp motor with a 5 inch propeller go at the bottom. This said, this has to be strong.

I've welded a lot of thick Al with luck. Nobody got hurt, no machine broke.
If I do 2 passes with lots of filler the crack should go away?

the cracking issue will be fixed by using filler.

i would preheat the metal, insulate it from the table so it doesn't loose heat so fast (even just sitting it on a bit of stainless will help). small cup (4-5), the least amount of cleaning action you can get away with, blunt tungsten angle to focus the arc.
do every little trick you can as it will help a lot.