When starting to tig weld, with the older Miller 180SD, for the first second, the arc is sort of violent and the machine makes quite a rattle and then it starts running fine. Not ever using any other 180SD or any other TIG machine for that matter, would this be considered normal?
Also, when would one know when to clean and adjust the spark gaps?
In general it means you are starting the arc with your tungsten too far from the metal.
Also get in the habit of "cold scratching" This means scratching the tungsten on the metal before starting the arc.
Because... Whenever you stop a TIG arc there is a certain amount of ionized metal particles in the plasma. When the arc stops the particles oxidize and cling to he tungsten creating an extremely thin oxide coating. This coating is a perfect insulator. By cold scratching you break this layer, giving you much better arc starts.
After about 5 years or so, and it is more necessary if there is a lot of metalic dust in your shop.
I would blast some high pressure air accross the gap once a year to blow particles out.
Bingo - My guess is the spark gaps are etched and are a bit wide or dirty. Takes a bigger hit - higher voltage - more power and a bigger rattle :-)
Mine doesn't ring the cage that is for sure! I have a new model - even newer - with the (wondering long term ill) LED readout.
Martin
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