Tig Welding thin aluminium

[rebekah_harper]

hiya all.

I have been tig wellding for a year now.

getting better at it. the problem I have is that I tend to weld thin aluminium 1mm and less.

I am using the chineese WSE 200. (yes I know).

it's actually good value for 2mm and thicker, no problem.

I have changed settings use low amperage and got the gas on high.

what I am finding is that sometimes I get a good run then other days ir blows holes right through. there are times when I can't get started for blowing holes then all of a sudden I am away, which I have to then fill in the holes.

so I have eliminated the material being at fault. as this occurs on the same piece.

I also have at times whilst welding, get pitting where it just pits the material at random.

I am coming to the conclusion that the machine is just not up to the job. possibly that it's not stable enough.

I am considering changing but cost is of issue. R-tech seem to be the way forward.

In the mean time can any one shed some light on what I possibly could be doing wrong. I have used green and black tungsten. am thinking of using white now.

kind regards

becky

 

[shenion]

Not much experience with thin aluminum but some things I find:

The fitup must be tight. Any gaps are hard to bridge.
I start by laying the filler on the joint and melt it on to the metal. That gets a bridge across any gap and then it is easier from there.
A footpedal on aluminum is a big help. As you get going, the metal heats up and you need less current.
A short arc length is critical.
Holding the torch at a steep angle may pull air in from the back of the weld.

"gas on high" may just waste gas and may cause venturi effects. Others have said it makes aluminum harder as it cools the weld pool too fast.

 

[rebekah_harper]

sounds good advice, I will apply some of these. a foot pedal I have although the operation of it is questionable. but I am getting used to it. I shall reduce the flow a bit. I think it's on 10 at the moment.

 

[Shox Dr]

I used one of those sets while working for a local firm. At first it produced very good welds in DC. But as soon as I started to use it in AC the problems started. We sent it back to the dealer 3 times, and on the third return the rep told me they were not interested in the machine and the boss was warned of the possible problems.


It's a pity you didn't post this last week, as a Kemppi 2300ACDC master tig has just sold on ebay for 1800quid.

However I don't think you will regret buying an R-tech, just don't scrimp on the amps

 

[FranV8]

I think at welding 1mm scrimping on the amps may be acceptable! (Although Shox is right, if you think you may want to tackle other jobs in the future, a little more investment now in capacity would be cheaper in the long run)

 

[milk]

i had a lot of trouble with the same machine. and it was about 40 amps out to what the display was showing and the foot pedal was terrible kept sticking. was sent back three times and took ten months to finally get a refund.

 

[FASTdan]

I started out on a WSE type machine (branded 'GIANT') - I thought it was great, and for what you pay I still think they are. But as soon as I got my R-Tech 250 AC machine I realised what a difference there can be between machines!! I can now do jobs at about 20-30 amps less than with the GIANT (assuming both readouts are accurate of course) with far greater control, arc stability etc.

Can't advise on the thin stuff as the thinnest I've tried is 1.6mm on the R-Tech (with reasonable success considering the lack of practice), but I suspect with some careful prep and practice 1mm should be achievable on it.

What I would also say is that the foot pedal I got with the GIANT was superb (not what you'd expect) and far more robust than the R-tech ones (I'm on my third, and even this one has had to be modified). The pedals really let R-tech down IMO but luckily their support is very good.

 

[rebekah_harper]

It seems that my suspisions are valid about the machines being generally good but just not on the detail.

£1800,- wow you say it as if it were a bargain. guess for what the machine is it most probably is.

my use of the tig welder is for building Radio Controlled model trucks in 1/14 scale. chassis rails and bodies mainly.

so my funding isn't fantastically liberal. so I am saving for an R-Tech because their service is great. I say this as they gave me heaps of advice on a machine that they didn't sell me and didn't realy recommend on having but still tried to help as best they could.

 

[Wallace]

Does your WSE 200 foot pedal have an amperage control knob? My TecArc 206i AC/DC Tig will give a range of 4-204 Amps using the control knob on the set but with the pedal connected I get 24-204 Amps. If your pedal has seperate plugs for switching and amp control, try a test weld on some scrap at the lowest setting then disconnect the amp control plug and do another weld to see if the current drops.

Mike

PS Is your machine the same as in this thread?

 

[rebekah_harper]

yes it does have a foot pedal but the dial does not have any gradients nor any indication what is min and max.

I don't even think it works as when you have it on either limit and fully depress the pedal it still evaporates both the work piece and the tungsten. short of buying a ampmeter to measure it, I'll never will know what the reality is but it's meant to set the max output for the pedal.

on a different note, what consumables do people use on their torch for thin alluminium.

the sizes of the cups and tungsten along what flow should be applied. the ampage I know but Is pretty impossible to say for sure what I am out putting.

tungsten I have tried 1.6mm red, black, green and am about to try 1mm white.

any guidance would be appreciated.

 

[langy]

I use white on AC, 5-7 on the flowmeter, On ally you need to keep the torch 90 degrees to the job, don't lay it over like you would on DC

 

[rebekah_harper]

Thank you.

I gave the white 1mm a go today, felt nicer but the thin ally didn't survive much.

It kinda starts of well but then it just melts away.

I did lower the flow to about 8 but I'll go a bit lower.

I'm thinking it's the frequency but at least some progress.

Any more ideas?

 

[justmental]

dont try and rush and lay a big long bead of weld as it gets so hot and will just melt away from you.
take your time and let it cool dont rush it.

 

[chevy2]

As others said thin ali is not forgiving,
poor fit with lots of gaps and you will struggle so spend a bit more time on fit it will help,

assume your tig is inverter not transformer type so dont bother with green tungsten,
i've been using grey ceriated lately but also use white,
if you have ac frequency adjustment then turn it up higher for a narrower more focused arc which will help and not wander causing the edge of thin material to burn away,
you can lay wider beads on lower frequency once you have more experience,

about 7-8 lpm gas flow on regular/not gas lense torch parts should work well.

 

[rebekah_harper]

not sure but I think it's an inverter.

when you say let it cool, basically get small weld on then let it cool, then do some more then let it cool. do this cycle until the job is done?

that's one thing I don't have, frequency adjustment. I think it's set at 60Hz.

I will be trying some more this afternoon so what I shall do is grab some scrap and ensure a close fit, clean and experiment with the balance and the dial on the pedal.

I shall add some pictures to show what is happening along with settings used.

any more tips will be welcome. I just need to keep going untill I can afford to change the machine over.

 

[justmental]

yes weld then let it cool a bit.
you will see as you are welding it will just melt away when it gets to hot this what you dont want.
try watching these videos will explain more than just reading.

http://www.youtube.com/watch?v=9KWdXUt3Bv8

http://www.youtube.com/watch?v=vWNZioJ_FOc

 

[derekm]

i have one of these. No problems welding thin stuff, I use either white or gold for ally and below 1mm I'm down to a 1mm tungsten. with this size tungsten you are using small cups(4,5) and low gas flows(4) and a carefully adjusted cleaning balance.

Foot pedal issues are easily solved as the pot can be replaced with one from maplin. How anyone charges more than 20 quid for a foot pedal is beyond me. its just a bit of tin bashing a pot and a switch.

the water cooler/tank is 1mm ally

 

[FranV8]

Derek - what's the pump you've got in that? Neat job.

Rebekah - it's an inverter, all the WSE units are.

 

[DrNik]

me me me ! its a washing machine pump

 

[FranV8]

Ah yes, I think I can see that now. I need to investigate why my CH pump based cooler has lost flow recently, could be related to the dodgy anti freeze I'm using, but could look for an alternative pump like that (have one that I'd earmarked for DIY mill coolant system) if it proves to be part of the problem. Saying that even on low flow the cooling effect remains excellent on the torch.