Alu TIG questions

[Delgado]

Hi guys, been awhile....

Back un the UK for a while and I've just started learning Alu TIG, something that I've never really done much of, and to be honest I'm loving it.

Anyway, on the finished job is there any way to get rid of the white marks from the cleaning action of the AC arc without ruining the finish of the alu? And how do you get rid of the dimples at the end of the weld, I've been dabbing a bit more filler than normal and trying to use the slope out (set to 4), but it still leaves a slight pit.?

Thanks!

 

[hotrodder]

Keeping the arc moving as the weld pool freezes helps with regards to dimples/craters. Could just be that you're adding the extra dab of filler too soon i.e. add an extra dab and then stop moving during slope out it'll still sink. Add the last dab during slope out just before the pool freezes

The etched zone... removing it will always have some effect on the surface finish of the ally. If the part isn't going to be polished or given a brushed finish etc then best way imo is to minimise the size of the etched zone in the first place- pre weld cleaning and machine settings. As the part weathers in use it'll end up barely noticable

 

[Delgado]

Thanks for that, I'll give it a go and post som pics next time I've got a spare minute.

BTW you're right, I think I've been adding that last dip a little too early.

 

[Delgado]

Some fotos

Here's some fotos to show how I'm getting on, definitely need to learn how to use the foot pedal, seems a lot harder with alu to control the heat by increasing the travel speed, end up going so fast that I cant feed the filler rod through my fingers quick enough

All the fotos are 4mm alu (no idea what grade as it's just some scrap that I found laying about) 4043 1.6mm filler, 2.5mm zirc tungsten, AC balance 50%, AC Freq 110hz, 125 ish amps, and no pulse.

 

[Delgado]

Also, is this what I'm aiming for penetration wise, and if so, how do I stop it cracking (I'm not back purging)? It's the back of an open corner joint with no gap, incase anyone's wondering.



Any help, advice or constructive criticism more than welcome.

Thanks in advance!

 

[Lewis Medlock]

Looks great

Jim

 

[hotrodder]

4mm Al with 1.6 wire... be easier with some 2.4 wire but looking good

is this what I'm aiming for penetration wise, and if so, how do I stop it cracking

Are there actually cracks or is it an 'oxide line' you're seeing? If cracks then pics needed. Oxide line usually more visible on the root side of butts, it should be a cosmetic thing i.e. DPI shouldn't find a crack and should pass a bend test without problems

I knocked out a few coupons of defects and a (not great) bend test here a couple of years ago. Was done hot with 2.4 wire (when 1.6 would've been a better choice for base thickness) to get a heavy oxide line. Note that were several other threads on the subject done at the same time- the pornographic close ups and some of the comments only make real sense if the other threads are read too, there were a few members with multiple personalities at the time Ron Jeremy being one of the regulars having a poke at someone. The marks on the bend test are from trying to get the coupon to bend properly (squashing it a vice and clobberin it with a hammer)

Radius for bend testing Al varies with alloy, iirc can be upto around 8T for some of the 6xxx series alloys

 

[Delgado]

Looks great

Jim

Cheers mate, still got a way to go yet though!

 

[Delgado]

4mm Al with 1.6 wire... be easier with some 2.4 wire but looking good



Are there actually cracks or is it an 'oxide line' you're seeing? If cracks then pics needed. Oxide line usually more visible on the root side of butts, it should be a cosmetic thing i.e. DPI shouldn't find a crack and should pass a bend test without problems

I knocked out a few coupons of defects and a (not great) bend test here a couple of years ago. Was done hot with 2.4 wire (when 1.6 would've been a better choice for base thickness) to get a heavy oxide line. Note that were several other threads on the subject done at the same time- the pornographic close ups and some of the comments only make real sense if the other threads are read too, there were a few members with multiple personalities at the time Ron Jeremy being one of the regulars having a poke at someone. The marks on the bend test are from trying to get the coupon to bend properly (squashing it a vice and clobberin it with a hammer)

Radius for bend testing Al varies with alloy, iirc can be upto around 8T for some of the 6xxx series alloys

Fantastic thread in the link, answered a few questions that I was going to ask on here, and a must for anyone learning to tig ally. I think the 'crack' is as you say, an oxide line, I've never seen that before and I guess I just assumed the worst Thanks for the advice about using larger filler, only got 1.6 but gonna get some 2.5 asap, the need for it became even more apparant when I tried doing some fillets with the same material as before....



Was experimenting with the pedal on this (max on pedal was 175a), but need to get out of the habit of backing off too much, although I think it'll get easier with practice. Had a few problems with the tungsten balling up too much, had the freq on 110hz and tried giving it a bit more negative on the balance (from 50%/40%) but didn't seem to help. Anyway, got plenty of scrap so I guess I'll have to play around a bit more to get the settings right.