8mm aluminum angle to 6mm tubing with a 200A TIG unit?!

[w124]

i thought welding 1mm was tricky, which it is but this was even worse. i've done 5 constructions of that kind and i had enough. now i saw drawings for 30+ of them some with 8mm gussets and not L=1m like i have done but 3m+. the material was hot to that point i had to put 2 thick mig gloves under my wrist, but the arc force was way too low at 200A cant tell how much time it took to lay down a 130mm long fillet on it but i think it would be quicker on 3mm thick L=1500mm...
i dont know what to think about it...
as much as im trying to avoid MIG - sure we have one with pulse but we dont have a tool to pre-heat.
its just like that- someone thinks i can weld details made of 20mm at 70A so 200A unit is more than enough for everything

and the only joint configuration per tube that worked well with this 200A welder

 

[Brad93]

200A!? Sorry mate but you're gonna have a serious lack of fusion on all of that. I hope its not loaded or structural.

I would of been nearer to 260A! Preheating aluminium is a rocky road. You've got to be sure of the grade and make sure your interpass temps are not stupid. I'd never heat over 120 degrees celcius. 75 better.

 

[w124]

Its a part of a balustrade from what i know. The lap or actually fillet joints (3rd pic 2 the same welds per tube and the small 8mm long welds on the edge of the longer leg of that angle im sure they have fusion. but the rest was like welding over an oversized tack or something like adding filler before the puddle gets started i mean that hissing sound it wasnt flowing in the corner after the first 20mm towards the center of the angle so after a while i had 2 puddles, no matter how long i waited used 1,6mm filler

it also needs to look at least decent as it will be painted
You say 260A, is it worth trying helium instead of argon with that 200A TIG or it wont change much?
or rent a 300-350A tig for a few days.
i have to do this, but i want to make the job easier on me, and MIG is not an option for me.

 

[Richard.]

Brads bang on the money. 200amps is not enough for such gages. One of my machines is 220 amps and even that’s too light. I think you need a minimum of 250 before that can be done properly.
Pre heat will help yes because it prevents the material sucking your heat away at start up but it doesn’t change the fact you still need lots of juice to bite into that.
Now you mention helium. This would make a big difference. Helium gives you Big Bang for current settings depending on the ratio you go with. A 30% he mix can make 200 amps bite like 300 amps. The difference is massive. The down side is it’s hideously expensive. You cannot just go out and buy balloon gas. It’s not pure enough you need proper welding helium.
Other things that can help with getting the best out of your machine.
Turn your frequency right down. 60-80hz. This will get things pooling up a bit quicker.
Turn your balance as far as you can in to dc negative but with out comprising the cleaning of the oxide layer. You should be able to get it to 80% neg and things stay clean. Deeper penetration is achieved with more negative polarity. Those two adjustments alone will help get the best out of your machine if that’s what your stuck with.
Ditch the 1.6 filler. I’d be using 3.2 on gages and current like that. A 2.4 would be the smallest I’d go to.

 

[Hood]

You say you have a pulse Mig, why not use that?

 

[w124]

Brads bang on the money. 200amps is not enough for such gages. One of my machines is 220 amps and even that’s too light. I think you need a minimum of 250 before that can be done properly.
Pre heat will help yes because it prevents the material sucking your heat away at start up but it doesn’t change the fact you still need lots of juice to bite into that.
Now you mention helium. This would make a big difference. Helium gives you Big Bang for current settings depending on the ratio you go with. A 30% he mix can make 200 amps bite like 300 amps. The difference is massive. The down side is it’s hideously expensive. You cannot just go out and buy balloon gas. It’s not pure enough you need proper welding helium.
Other things that can help with getting the best out of your machine.
Turn your frequency right down. 60-80hz. This will get things pooling up a bit quicker.
Turn your balance as far as you can in to dc negative but with out comprising the cleaning of the oxide layer. You should be able to get it to 80% neg and things stay clean. Deeper penetration is achieved with more negative polarity. Those two adjustments alone will help get the best out of your machine if that’s what your stuck with.
Ditch the 1.6 filler. I’d be using 3.2 on gages and current like that. A 2.4 would be the smallest I’d go to.

Our tig is 169A at 150hz and 200 below 85hz balance was set at 85 (max penetration) its a invertec v205t
I used 1,6 to feed a small amount of filler into the puddle then i moved the torch a little back and added more.
I think price for the gas is not an issue it will recompensate the time to make it and ill be able to use 3.2 filler

 

[Richard.]

Good machine just undergunned for the job.
Do a price comparison between hiring a bigger set vs a bottle of helium and see what you get as a better deal.