Ac tig reverse polarity arc won’t hold

[Ayushk]

Hi there,
New to TIG!

I’m have a problem with AC tig where the arc won’t hold in reverse polarity welding Aluminium but will hold in straight polarity. Same setting and location of ground.

Any thoughts

 

[Erie Fred]

How do you AC tig weld using reverse polarity ?
Or straight polarity for that matter ?

and what do you mean by "hold" ?

 

[chrismac]

As Erie Fred says, straight and reverse are terms used in DC welding not AC, (alternating current) you can probably hold an arc using DC but you will achieve very little.

 

[Hood]

With Tig, torch goes to negative and clamp goes to positive. Doesn't matter if using AC or DC, you use it that way.

 

[BrokenBiker]

as hood says, the torch/ground never move on tig whether you are using AC or DC, its always Torch Negative. AC cant be straight or reverse polarity, by nature it is changing a number of times per second based on your frequency settings.

now, if i have to guess, i would say you have swapped the leads to torch positive, but your AC balance is set at 70% ish negative, but as you have swapped the leads, that is now 30% which means 70% of the time the current is trying to blow your tungsten to bits...

 

[Ayushk]

With Tig, torch goes to negative and clamp goes to positive. Doesn't matter if using AC or DC, you use it that way.

From what I research when trying to weld aluminium in AC torch is in positive terminal and opposite to DC. This what I’m trying to do with the torch being in positive terminal however my arc will strike but won’t establish and hold.

 

[500e]

Read #4 #5 again @Hood has possibly welded more alloy than most and for safety critical parts

 

[Jack Ryan]

TIG is electrode negative - even when using AC.

If you are welding AC with 30% cleaning and then you reverse the leads, you will be using 70% cleaning and the tungsten with vanish.

Jack

 

[Hood]

From what I research when trying to weld aluminium in AC torch is in positive terminal and opposite to DC. This what I’m trying to do with the torch being in positive terminal however my arc will strike but won’t establish and hold.

You need to do better research I am afraid.

 

[BrokenBiker]

From what I research when trying to weld aluminium in AC torch is in positive terminal and opposite to DC. This what I’m trying to do with the torch being in positive terminal however my arc will strike but won’t establish and hold.

Where have you read this? I did a lot of research before buying a tig welder at the start of this year and i never found anything that said you should change torch connections for AC, everything i found told me to set it torch negative and leave it alone.

Put the torch back in the negative socket before doing anything else, set your ac balance to 30% positive and your frequency to 120hz and you should be able to weld any aluminium within your amperage capacity. Any other issues will be down to technique then.

 

[Popcorn]

Read this probably the best intro you'll find to TIG welding:

Thread 'Aluminium tig guide getting started.'

Jun 13, 2016

As has been requested by a small number of members I'm happy to start a small guide as a starting point for newcomers into welding aluminium. The idea is to simply give you a starting point so your new toy can be taken from the box and dialed in without the grief of guess work or diving through countless threads with lots of compromising opinions and info.

There are literally thousands of combinations as to what can be done to weld it I'm just going to talk about the meer basics and after that it's up to you.

I'll do it over time and generate a few posts and get some pics in it to help...

• Richard.
• Replies: 278
• forum: TIG Welding

• 

 

[carbon]

From what I research when trying to weld aluminium in AC torch is in positive terminal and opposite to DC

Definitely need to do better research, I think you've got mig and tig confused. Mig welding aluminium with DC is possible when the electrode is connected to +positive and the earth clamp is -negative. Tig is always electrode negative and clamp positive.

 

[zzr1200]

From what I research when trying to weld aluminium in AC torch is in positive terminal and opposite to DC. This what I’m trying to do with the torch being in positive terminal however my arc will strike but won’t establish and hold.

Where is your HF coming from the welder or a HF add-on unit???

 

[500e]

Are you feeding the filler by hand or is it off a reel.

 

[zzr1200]

A pictures of your welders setup would help, no end.....