First things first, there is an error in the R-tech user manual:
'Set at 50% this provides balanced control suitable for most AC Welding. 30% is max cleaning and 70% is max penetration'
On my machine, 30% is max penetration and 70% is max cleaning - this seems to be correct as R-tech then go on to say:
'Tip. If you are welding close to the tungsten limits, I.E 200amps on a 2.4mm tungsten and the end of tungsten is wobbling and falling off, turning down the SP% will give better tungsten stability'
So I guess the manual is wrong slightly.
This is a must read for RTechers.AC BalanceThis sets the % of electrode positive used during AC welding to provide a cleaning actionas alloys have a oxide layer that has a higher melting temperature than the base metal andthis needs to be lifted off.So you can control the amount of cleaning or penetration.Too much cleaning will cause the tungsten to wobble and split, Too little cleaning can resultin a dirty dull weld.So as you increase the % the more cleaning will happen however less penetration will beachieved.For most situations a setting of 30 - 40% will give you a good clean weld finish, If you goabove 50% you will find the tungsten will overheat and the end can fall of into weld pool.If you find you are getting tungsten wobble using 30-40% balance then you may need to goup a tungsten size.
In work after acid pickle which is mega clean you still get the white etch zone when you weld as it's cleaning the material still slightly.Stop scrubbing the plate with a wire brush and set your balance to 30-35% then you will get the etched zone.
Remember the "white bands" is only the removed oxide layer from the AC pos cleaning cycle. If you remove it before hand by scrubbing it with a brush and acetone etc then there will be nothing left for the positive half wave to remove so the etched zone will be reduced.
Those runs look ok. Don't get over carried away by not seeing the etched zone. The fact that your beads look clean in the pic is what you should be aiming for. It must be removing the oxide layer otherwise those runs would not look like that. Really nothing to worry about mark.No wire brushing rich and still no white etch. If I go any more cleaning on the ac balance the tungsten will blow it's self apart.View attachment 64778
It's the oxide layer that is lifted during the cleaning cycle of the wave. It's a fact that the more of the oxide layer that is removed before welding the etched zone is reduced. My pic above illustrates that perfectly. Tbh I couldn't care less how much of an etched zone is produced when I'm welding. I'm looking for flawlessly clean runs only. In a lot of cases the etched zone is only another thing to remove.In work after acid pickle which is mega clean you still get the white etch zone when you weld as it's cleaning the material still slightly.
What do you think it is Hugh? So frustrating! Surely that's not right?
Disagree. I think the machine is fine. Why people get so hung up on the etched zone around the weld is beyond me. If the AC cleaning was at all faulty there would not be clean welding beads been produced. A good way to check if it's doing what it should be is play with the balance and see what it does to the tungsten if it balls up the more ep you give it then it's doing what it should do and you need not worry.Duff machine - has the new one arrived yet?