balance or not?

[Harrys dad]

While i've been having issues with my murex tradestig (now in for repair) research i've been doing and people i've spoken too have mentioned BALANCE, which my old set doesn't have, can anyone advise me on how beneficial this is please?
Being a mechanic by trade it's not in every day use but occasionally for my restoration projects (ally crank cases etc).

 

[BrokenBiker]

Ac balance allows you to alter how much the ac 'cleans' the weld area.

From what I can see it's a percentage value and if you set it one way it cleans more but penetrates less and set it the other way and it cleans less but penetrates more

 

[Harrys dad]

So my set without balance control is pre set at 50 50??
I guess that you would get more control and be able to get better welds when repairing old alloy parts with a machine with balance then?

 

[Richard.]

Balance is based around polarity.
Ac Tig is a fluctuation of dc+ and dc- . The balance is a % you set on the unit of how much time it spends in a polarity. The more you set it towards the positive polarity (current to electrode) the better the cleaning action but this offers a lot of load onto the electrode which melts it and creates a ball. Too much and you'll Start loosing the tungsten as it melts away. Going heavy on Dc neg offers less cleaning but the tungsten remains very stable as its not carrying much load (More heat into the job) this offers deeper penetration too. The trick is finding the "balance" (70% dc neg is usually about right).