Ernie Leimkuhler wrote:


There are only a few companies that make tungstens, everybody else just
relabels to sell under thgeir name.

Well, I'm learning, slowly, what works and what doesn't. But, I got
a major chunk of my first TIG project done (stand for surface plate).



Sounds like your spark gaps need to be cleaned and regapped.
There should be a hatch that gains you access to the HF generator.
The HF Gen has a pair of spark gaps that need to be cleaned every 5
years or so, depending on environment.
You have to remove the points, clean then gently so they are flat and
clean, then put them back in and set them to the factory gap.
I find that puting them in a drillpress works well, and just spin a
piece of silicon carbide sandpaper against the face with a flat bar
backing it up.
The idea is to get it very flat and smooth.

They ARE very flat and smooth, and the gap is about right. They make a
loud hiss, no buzzing or popping. And, the hiss is the same whether
the HF is working or not on that start. So, I think it is something else.


Another point.
Get in the habit of "Cold Scratching".

Every time you stop and arc, there is a little cloud of ionized metal
particles caught in the plasma stream.
When the arc stops, they will collapse onto tyhe trungsten point.
These particles will form an extremely thin oxide layer that is a very
good insulator.
Scratch the tungsten point on your base metal before hitting the foot
pedal to break through this coating.

AHHH, I think this is it! I'd never heard of this, and it isn't in any
of the books, either! But, I did notice that anytime I accidentally
touched the electrode to the work, I would get an excellent arc start
the next time. Just that I was doing by accident, but I hadn't actually
figured out the connection, yet!

If you get in the habit of this you will get much more consistent arc
strikes.
Just be sure to NOT have the foot pedal down while doing it or you will
contaminate your tungsten.

Well, I did this a fair number of times with the 2% Thoria electrodes.
I would get a green flash, and then it would go right back to a smooth
arc. But, thanks again for getting me to give up on the pure W
electrodes. Never again!

Jon