Sunday, July 25, 2010


I'm looking into adding pulse arc welding to this welder. Pulse arc welding is like TIG welding. By adding Argon gas through a special gun with a tungsten tip will produce a very hot plasma arc that will melt almost any metals together( including aluminum, gold and silver).  This welder was originally designed to use a contactor and  can easily be converted to activate an argon gas solenoid and a retractable tungsten tip. I will appreciate any input. 


  1. Sounds exciting. I have just received my caps and was about to make the case for my welder. I might have to leave a little extra room for the gas solenoid in there :-) Can't wait to see what you do next.

  2. Just found your blog from searching u-tube for spot welders 2 days ago. Read through every post and all comments. Did same for Ultrakeet in AU. I am very impressed. Fritz is the definition of a "renaissance man" - he does it all!

    Anyway, it seems this project is about to take a major turn in direction. Like many others, I would like to build one of the dual pulse versions of this welder. Unlike many, I have the experience and expertise to do so. However, as I have gotten older and busier, I like to avoid re-inventing the wheel as much as possible.

    To that end here is my question/request. despite my best efforts I have been unable to find the schematics, PCB layout, and latest BOM anywhere on the blog. Are these hidden in one central location, or do I need to send cash?

    I guess what I am asking is for an overall update on the overall status of the CDW version 2 project - as in current schematics/rework list; PCB versions/rework list & availability & cost; Best cap's folks have found; pseudo-code for operation (I know Fritz does not want to give out source code, but an overview of key design elements would be helpful. And yes I have been to Jiri Pittner's hobby page for his take.)

    Also, I have a question/comment: Is the time unit 'Ms' Mega seconds or milli-seconds? My understanding of prefixes is that 'M' is Mega or million and 'm' is milli, or 1/1000. I've seen seconds as 's', 'S' and 'sec'. I doesn't make sense that Mega seconds is right since there have been no reported meltdowns or explosions!

    In any event, thanks for a great project that has renewed my interest in actually making a project after many, many years. I look forward to hearing back.


    p.s. My practical motivation are the stacks of dead NiCd and NiMH batteries I have gathering dust around my shop and my friends shops and my colleagues shops... I smell a side business! Ultimately converting these packs to LiION is the goal hence the questions about A123 - right?

  3. Alex, thanks for all the nice things you said. This project is not really going to make a major turn in direction, I'm just adding more optional functions to the existing welder which will give the operator more welding choices.

    I was selling the PCB's for this welder and temporary closed the online store to give me time to work on a couple of things.

    How this welder works: The control PCB is powered by two separate 24V windings, one supplies power to the micro processor and the other winding supplies power to recharge the capacitor. The processor takes voltage readings every 50 to 100uS(MICRO SECONDS) and decides if the capacitor charging or discharging mosfets have to be turned on or off. It also drives a LCD and controls PWM charging, sound, Pulse 1 and 2 Pulse widths and turn the Mosfet PCB on and off.

    This welder will cost you, depending on how nice you want to make it between $500 and $600 to build.

    Ms stand for "Milli seconds ". 10Ms will be 10 thousands of a second.



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