I posted a while back when I fixed the HF on my welder. I'm having a recurring problem that existed before and after the fix, not as bad now, but I might be just telling myself that. When I'm welding steel on HF start only, the HF buzzes like it should, but the arc doesn't always start. On a freshly ground tungsten this doesn't happen. My helmet will sometimes flicker like it's about to arc sometimes, but the arc just won't start. If I let off the pedal and just touch the tungsten to the steel, then lift it and start like normal, it works fine. I'm thinking it's maybe something to do with the oxidation on the electrode or something, but I'm not sure. Once I've run a weld, if I start again before the postflow is over, it works pretty much every time. Should I just turn up the post flow? I have the timer now set to 6-7 seconds, and with stainless I often kick the pedal after letting off to restart the timer for more flow... basically I don't use the setting and just do it manually.

With constant HF on aluminium, it does this, but less often. I don't ever touch the aluminium to the electrode, I always thought that was bad (like when you blow out the end of it from accidental touching), but I was never "formally" trained in TIG so a lot of this I'm guessing or making assumptions based on what seems logical. Anyway, with the aluminium, if it doesn't start, and I tap the filler rod anywhere on the piece, my helmet goes dark a little early and the arc starts right up like it should. The whole thing is kind of annoying, but not to the point where it's making me not want to weld or something. I guess I'm just doing something wrong?

My gaps are set to 0.008 or whatever it says on the door, new tungsten points, replaced some parts on the HF board, and the intensity dial is set about halfway up on the machine.

 

Have you posted this problem on millers discussion forum? I had some problems with my welder before & those guys helped me diagnose the problem. Just a thought. There website is www.millerwelds.com.

 

mine does this sometimes too if the tungsten is dirty or contaminated from touching the puddle or metal i was welding (i know i suck, but it happens lol)
but it would only has happened a handful of times, and it's never a big deal because at that point i pull the tungsten and re-grind it.

 

Yeah this isn't from dipping it in the puddle, I'm 100% sure of that.

 

what machine?

 

Syncrowave 500, 1979 model.

 

but you said it doesn't happen on freshly ground tungsten (aka clean tungsten)
thats the point i was getting at. mine does this when it is dirty.