hello I'm building a TIG welder and have found the output from my stick welders to be not so good for aluminum(60 Hz on one). I've heard that high frequency AC is the way to do AL but am not sure what constitutes high. I do have a nice miller gas driven welder also that is maybe triple the frequency of my line driven one but still had issues with it. does anyone know of an actual # ? I may be able to build an inverting PWM supply eventually to do this but am not sure what I would need it to do. does anyone have any data that might help? any data/tips about aluminum would be appreciated, thanks in advance. FYI I do understand why AC works so much better on AL, what with the oxides that are always present.
NO... the TIG rods are uncoated and will not be able to create the shielding gas like coated rods would when used in an ARC welder. TIG (Tungsten Inert Gas) uses a shielding gas supplied from a tank, the aluminum rods are used as filler material and metled into the weld by the operator by using the arc from the tip as the heat source. Two different welding processes, hence the need for two different types of rods...
Best not to play around with jury-rigged equipment if you don't have to. The best option would be to simply buy a purpose-made Inverter power source for TIG. The high frequency is secondary to the main AC power, which is by default, 60 hz. In other words, the high frequency is simply added on top of the main AC current. A lot of inverter power supplies for TIG allow you to alter the MAIN power AC frequency to above or below 60 hz. This can be helpful as increasing the frequency produces a somewhat narrower arc. The high frequency is little more than highly amplified radio noise that is injected into the main power signal. It consists of a broad range of frequencies, usually in the range of kilohertz to megahertz. Beneficial features to look for in an inverter include high-frequency generator, square wave, AC wave balance, AC frequency adjustment, high frequency intensity adjustment, and a foot control. Pre-flow and post-flow controls can also be convenient if you expect to be doing mass production jobs. I consider other features, including pulsed TIG, to be mostly a waste of time and money. With respect to the previous poster, the high frequency DOES help with the cleaning action for welding aluminum.
The High Frequency used in aluminum is for the starting and stabilizing of the ac wave. All the h/f will do is allow you to start the arc without touching the tungsten to the work and stabilize the arc itself. The h/f does not pertain to the alternating current frequency (50 - 60 Hz). The ac current does the cleaning of the aluminum to some degree (not eliminating proper prep and cleaning before weld). You could buy a high freq add on unit that could help, check with your local welding supplier or look it up on line. Edit -- Here's a thought go to some of the welding power supply websites and find a manual on a tig machine and see if they have a schematic on the high freq. hidden within the service manual. You could then get an idea of how they did it.
