Quote:
Originally Posted by AshG
you will only need about 120-130amps to tig that up. i could do it for you if you can wait a few weeks for me to get my work load down a bit. that is an hours work max including making the plugs
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maybe if its preheated my zetec sump i welded at 140-180a 20% cleaning but my tig is fixed freq @ 75Hz (i think)
ac tig settings are quiet simple and you have to bare in mind the propertys of ally it melts at a lower temp but conducts heat realy well and forms an oxide layer on the serface in air but if yor weld pool runs out of all oxygen you get a thing called arc flutter (moving the arc will help)
Amps = total power you will need a loads more than dc on steel and also (effected by ballance) the work piece soaks up heat real well on ally so you are loosing power via heat conduction and reversed current
ballance or +/- = this is the amount of ratio between welding (normal) and inverted (cleaning) curent. this is also a % of heat direction too much cleaning and it burns out your tungsten not enough and you will have poor penitration and poor weld pool formation.
another effect this has is it changes the width of the weld pool so more cleaning makes it shallow and wide less deep and narrow.
Freq/Hz = most low end units are fixed but now more common. this will effect the depth/width of the weld pool mainly.
remeber everyone personalises thair own way of setup but a few basics will need to be applyed
high pureity argon is a must (99%) at 10Lpm,large cup , clean area to be welded (avoid grinding or steel contamination) i find stainless wire brushes are good and red scotchbright pads just befor welding, blunt point on a sutable tungsten (i use gold ones for eveything) 2.4 or 3.2 (bigger than dc per amp),
if you have foot control use it its ideal for AC as as everything heats up you can reduce your amps
start with 25-30% cleaning/ballance (showen in all sorts of ways)
60-100Hz freq
pulse off, up and down slope are not too importent
1 sec pre and 2 post gas
2.4mm 4043 filler for most cast allys 5356 for sheet
hope that helps
