I bought a nice used TIG welding machine the other day. It is an Italian make you might have never heard of. It is a ca. 2002 "SELCO Genesis 200 AC-DC" with water cooling and lots of nice features and it is in perfect condition - BUT! - It came without a foot pedal for the amperage control. Especially for welding aluminum, the use of a foot pedal makes life alot easier (to have proper heat control). So I searched the web to find a pedal that would work with my new welder. But finding the combination of a 10k Ohms potentiometer control with a 7-pin connection plug of military standard and a reasonable design/rigidity was in vain...
During my search I got the impression that there is some kind of "two class society" when it comes to welding equipment. You either find cheap stuff from the far east or the high end manufacturers stuff which I sometimes found ridiculously expensive.
Finally I decided to build a pedal by myself.
The only components I did not have was the potentiometer, the signal cable and the plug. I got the first two from an electronics market for less than € 20.-. All other parts (except for the sheet metal) came out of my scrap box. As an example: The switch - needed to initiate the arc start - is a micro swith from the controls of an old Honda motorcycle. My research for the plug gave prices around €50 so I decided to build that one as well. Attached are pictures of some sketches I made, of the pedal and the DIY-plug.
It was fun to build and it works perfect. The weight is about 4 kilos so it does not hop around when pushing the pedal.