Thread: Footpedal
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Old 12th Jul 2019, 9:25 am   #10
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 13,094
Default Re: Footpedal

There are two approaches to TIG welding.

In Europe, it's most usual to have a button on the torch and to programme the machine in advance.

Push the button and the arc comes on at your chosen low current to allow you to start and build a pool by lingering in one spot. Release the button and full current comes on for the main welding. Push the button again and it falls to the lower current again to help filling in the end pool so you don't end with a pit. In addition to this you ca also (if your machine is posh enough) select pulsed welding where the main welding has a 1 second cycle between high and low power. Set right, this gives you a metronome and you work along going drip, move, drip, move timing drips from your filler rod. It makes for a regular looking weld pattern.

In America, things are different. Their most common setup has a pedal. Dial up your chosen current on the machine, and that's what you get pedal to the metal. Foot off and the current is off. Press a little to start, build a pool then put your foot down and get going. If you set the current more than you really need, you have to hold your foot in position, but you have reserve power you can bring in when your weld happens to go past something that pulls extra heat out of your pool. If you want pulse welding, pulse your foot.

Pedal welding is good on irregular shapes, you can just adjust as you go. Button welders either have to keep stopping to twiddle knobs or need an assistant to shout at.

Button style can look more uniform, almost the product of a robot. Suggest to an American that he welds like a robot and a hail of bullets is the likely reply.

Welding in a nice seated position, a pedal is great. Standing on one foot to operate one soon becomes tedious. Welding underneath something and arranging a pedal against a wall or something is starting to get desperate.

Welding equipment firms ask the ransom of princes for their pedals. Many welders just buy a second-hand guitarist's pedal, maybe change the pot, chuck the PCB and add a cable and connector.

I'm set up for both modes, even both at once. But the machine uses a micro in the pedal and a digital interface. OK, I could have programmed a 1-chipper, but the time would have earned more than the cost of the engineering porn one from Germany. It is awfully chunky and doesn't skate around.

The machine I use can be switched to AC output, variable frequency, choice of square wave or sine, and you can distort the wave to get more tungsten -ve time or less. So think of a 7kW function generator. Musical, yes, but not exactly a nice sound.

David
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