Page 2 of 5 FirstFirst 1234 ... LastLast
Results 11 to 20 of 50

Thread: PUK welders

  1. #11
    Join Date
    Jul 2009
    Location
    West Midlands
    Posts
    1,352

    Default

    I was more interested in having a look at the difference between The Smiths Little Torch and the Orca, but if we go we'll ask for comparisons. We're really busy atm, so unlikely we'll go.
    Jules

  2. #12
    Join Date
    Aug 2009
    Location
    London
    Posts
    886

    Default

    I'm hoping by the time IJL rolls around this year I'll have saved enough to get one (hypothetically of course) so might see if anyone's demoing them at the show.

  3. #13
    Join Date
    Feb 2011
    Location
    Scotland
    Posts
    2,601

    Default

    I don't think I have ever been sent a newsletter by Suttons but one arrived today advertising a PUK welder upgrade with tacking facility!! Have they been reading this forum by any chance?

  4. #14
    Join Date
    Jul 2009
    Location
    Cornwall
    Posts
    3,168

    Default

    I got the same thing. Maybe they have.

  5. #15
    Join Date
    Aug 2009
    Location
    London
    Posts
    886

    Default

    I have it too! They are just taunting me with their wonderful toy that I can't afford.

  6. #16
    Join Date
    Jun 2010
    Location
    Cardiff
    Posts
    988

    Default

    I can't even afford to read this thread ...

  7. #17
    Join Date
    Feb 2011
    Posts
    1,744

    Default

    i looked at the vids and downloaded the brochure and it is for sure a sexy-looking thing. But I don't think I would ever be in the position to justify the cost of such a thing. I think my time and money is better spent learning how to solder properly.

  8. #18

    Default

    For what it's worth, I looked at these machines a while ago and decided to build my own . It works really well on steel and stainless steel but I found working on silver it was far from perfect. The problem is that silver has a very low surface tension when molten so it blows out of the way very easily with the arc wind, not to mention the fact that silver is so thermally conductive so getting heat into it can be a challenge in itself (and there were more than a few burt fingers as I was looking at my handywork and a second or two after the weld was finished the heat reached my fingers.). Now with carefull selection of the operating paramiters you can get acceptible results (I made a little ruby pendant for mywife with it by welding a jump ring closed and then welding that to a bezzel) but in general I found it more faff than it was worth. I realise the companies that sell these machines have spent lots of time perfecting their system so are almost certianly better than mine and mybee I never got quite the right settings so maybee my experience is somewhat biased.

    I would say try before you buy and definitly on the metal you intend to use it with.

    I remember reading somewhere they are very good for titanium, although Ihave never tried it. When it is up and running and set just right I can do jumprings supper quick though.

  9. #19
    Join Date
    Mar 2010
    Location
    Weymouth
    Posts
    14

    Default

    Inspired by the self build. I have been tempted, read all the websites and even put together a component and sources list, but just had a feeling that it would not be as easy as simply rigging up a bank of capacitors and firing them.

    However, Binraker, it's great to see you had the courage to build the machine - respect.

  10. #20

    Default

    Quote Originally Posted by Nyc View Post
    just had a feeling that it would not be as easy as simply rigging up a bank of capacitors and firing them.
    Yes it is a little more complex. The idea is basically a mechanically actuated scratch start TIG welder with arc timer. The magic is in the timing. The order of actions is something like: turn on gas, wait a bit for it to flow and cover everything, start electrode retract (it will take a millisecond or 2 to get moving and we want to turn on the caps just before the electrode leaves the surface, wait a few milliseconds, turn on cap bank, wait the desired amount of weld time, turn off cap bank, wait a bit to allow the user to remove the item, turn off the gas and release the electrode. It's all millisecond stuff so its not fast but it is "fast" from a human point of view.

    You can then select the charge voltage and arc duration to vary power and total energy supplied. If I had found it useful more I would have put in a number of parallel systems so that you could profile the voltage throughout the weld cycle and get a bit more control. you could also change the retract solenoid voltage to change the mean arc length or have a shorter retract distance so that full retract is at optimal to distance. or you could use an overlaid high speed high voltage ionising pulse to start the arc which will give more arc profile control but will limit your ability to weld into corners. There are numerous possibilities...

    The switching of the cap bank needs to be fast (sharp edges) and low resistance so very careful selection of transistors required MOSFETs will do the speed but not the power so you really need an IGBT with a hard driving circuit to keep the speed up. this needs to turn on an off in 100us territory to stop the transistor dissipating too much energy. The inherent ESR and ESL of the cap bank with throttle the energy dump quite a bit so it will probably be the limiting factor.

    If you want I will post all the details of my machine and the code if you want to build a copy of it as a starting point for your own investigations.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •