Need advise Welding thin aluminium sheet 0.8mm

[gt6s]

As title Been trying to weld this stuff. Foot pedal set at max of 25 amps tho full pedal blows straight through it. Tungsten is 1 mm. I have found on outside corner weld cut edges just burn away from each other, even with angle iron backing. Won't even tack. Tried folding a 1/4 inch 90 degree on one side makes for easier setting up but as soon as arc strikes the cut edge burns back folded over edge is okay tried laying a sheet of copper just back from the cut edge sort of works but NOT GOOD ! The reason I am trying this is firstly for ally TIG experience. Secondly I am building a Triumph Gt6 as a road legal race car and the Aluminium fuel tank has to be enclosed. Also I have a load of this stuff and I would prefer welded rather than pop riveted. BTW also tried 1.6 tungsten, pulse settings and winding up the frequency all those no go either.
ANYONE ?

 

[eSCHEn]

I'm not an ally welder but I would approach it the same as any thinner material. Nice super sharp tungsten to really focus the arc nice and narrow; have a good fit up on the material; lay the rod on top and strike against that if necessary.

Edit - also GET IT CLEAN AS CLEAN CAN BE!

 

[Chris Stevens]

You should be able to weld coke cans with a Tig no real problem. Can you weld 2mm sheet ok? If so try welding it with the same settings as you are using for .8mm and see if it still welds ok. If it does weld the 2mm, then get someone to watch the amps on the front of the machine when you are actually welding and see what they go up to.

 

[gt6s]

Have no 2mm sheet at present, don't think so anyway may have a few bits of 3mm. New first AC/DC TIG ! Been working on stuff that actually needed doing like repaired a previously modified and later broken starter motor also shortened a LT77 gearbox lever remote. Bar a test weld on a half inch thick gearbox casing.
I have a notion on how to do this but I will not be out to workshop again till Monday.
I have seen on u tube coke cans being welded It was said it was not easy OR PRETTY ! Also Coke can ends do not have cut edges. This stuff is so thin even the earth clamp puts dents in.

 

[Richard.]

Fit up is absolute key here.
0.8 is quite thin but far from difficult once you know how.
Part of your problem is imo too low on the current and using a pedal. Your tapering into it from 0-25 amps no doubt slowly and giving it too much time under the heat to open up.
Believe it or not once you have a sound tack in place you'll easily weld it. So get you tack in on an outside corner at 40amps. Use the torch switch only and turn off any up or down slopes. Instant current fill straight in and instant off. Practice on butt joints at 50 amps. Once that tack is there you can pedal away controlling the current to the end using your tack as a point to start.

 

[gt6s]

It has actually been fitted up very nicely. The folded edge helps a lot. You could well be right about tapering in but I am not even getting near full pedal 25 amps. Will certainly try tacking it up on the torch sw without slope in / out. Ta.

 

[Richard.]

It has actually been fitted up very nicely. The folded edge helps a lot. You could well be right about tapering in but I am not even getting near full pedal 25 amps. Will certainly try tacking it up on the torch without slope in / out. Ta.

Although it feels wrong the means to success is all about cracking up the juice and having the tack go in as quickly as possible. Lower current may take a second longer before it's ready for fill but that second has cost you the joint.
Practice on butt joints. Get a feel for the speed.

 

[Chris Stevens]

It has actually been fitted up very nicely. The folded edge helps a lot. You could well be right about tapering in but I am not even getting near full pedal 25 amps. Will certainly try tacking it up on the torch sw without slope in / out. Ta.

If you cant see the amps the machine is displaying while you are welding, it might be putting out 50amps or more. Its very easy to check, but if you are a beginner without a fair number of hours practice running bead on plate, maybe not that great an idea to be welding .8mm, until you can weld heavier material reasonably well?

 

[optima21]

don't know if you have seen this video of tacking thin aluminium

 

[PSweeney]

Richards advice helped me no end, quick hot tack with a dab of rod, then weld of the tack

 

[gt6s]

Nope full pedal is 25 amps. easy checked just floor the pedal without striking arc, gives readout. Agreed 0.8 stuff is not ideal to learn with.It just I have mountains of this stuff, and a job to do with it. I got the 0.8 stuff to skin a space frame race car I was building years ago which now will never happen, too many other projects. Thing is I also have some 1.25 sheet, problem with it is it is all etch primed. No point even trying to TIG that.

 

[Maxakarudy]

If you are just starting tig welding ali, then IMO start with thicker material, thinner ali 0.8mm is the most difficult place to start.
1.5mm is a starting point, welding ali is all about speed, it likes it fast and hot, trying to warm it up to get the puddle going started isn't the way it's done.
Just practice getting the puddle under control, then progress onto joining.
Martin

 

[Shox Dr]

What's your arc length?

Needs to be real tight<2mm and consistent

 

[gt6s]

Arc length is fairly tight actually Watching that vid he talks about a slight overlap and hitting it hot. Which I have not tried either of. Will have a quick play tomorrow. Only a quick play as I really do have to clear out my small workshop for a welding table. And yeah I fully realise that learning on 0.8 is anything but ideal.

 

[Chris Stevens]

If you are just starting tig welding ali, then IMO start with thicker material, thinner ali 0.8mm is the most difficult place to start.
1.5mm is a starting point, welding ali is all about speed, it likes it fast and hot, trying to warm it up to get the puddle going started isn't the way it's done.
Just practice getting the puddle under control, then progress onto joining.
Martin

Spot on............I get the feeling that the net and You Tube videos mean that a lot of beginners seriously feel there is no need whatsoever for hours and hours of bead on plate practice, and they can get straight onto the more advanced stuff before even getting the basics.

In the long term I think the perception that all you need to be able to Tig weld to the same standard as someone who has spent years learning, is a Tig machine and a connection to the net, probably leads to a fair number giving up, as the idea of being able to win a marathon before even being able to walk is now very common indeed, and is really pretty silly.

 

[langy]

Fit up is absolute key here.
0.8 is quite thin but far from difficult once you know how.
Part of your problem is imo too low on the current and using a pedal. Your tapering into it from 0-25 amps no doubt slowly and giving it too much time under the heat to open up.
Believe it or not once you have a sound tack in place you'll easily weld it. So get you tack in on an outside corner at 40amps. Use the torch switch only and turn off any up or down slopes. Instant current fill straight in and instant off. Practice on butt joints at 50 amps. Once that tack is there you can pedal away controlling the current to the end using your tack as a point to start.

Good advise Richard, learning on .8 ??? Wth

 

[Chris Stevens]

Good advise Richard, learning on .8 ??? Wth

This is the net..............learning on coke cans is quite possible.........................lol

 

[Maxakarudy]

A coke can is quite often used as reference to skill levels with tig welding, can anyone show it done, not end to end, but along the sides or is it just pub talk?
Martin

 

[Chris Stevens]

A coke can is quite often used as reference to skill levels with tig welding, can anyone show it done, not end to end, but along the sides or is it just pub talk?
Martin

Mate of mine has a plane made of welded coke cans hung up in his workshop.............its quite possible, but not the sort of thing for a beginner.

 

[Richard.]

A coke can is quite often used as reference to skill levels with tig welding, can anyone show it done, not end to end, but along the sides or is it just pub talk?
Martin

End to end is a challenge in itself as the ends are as thin as any other part of the tin but again it's the first couple of tacks that are the hard part once they are in you have a surprisingly good chance of finishing it up nicely.
Remember cans are anodised so if your looking to try it you'll need to take that off before making a mess.
Last ones I did messing about I prepped em back to clean Alu and did it with a course file.