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spot welder from old microwave really interesting and seems easy too

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  • spot welder from old microwave really interesting and seems easy too

    See some of the things this guy does but the spot welder is a great idea for me.Alistair
    Please excuse my typing as I have a form of parkinsons disease

  • #2
    I like it... I didn't even know I "needed" a spot welder till now.

    Thanks for posting that,


    • #3
      Thanks for posting this Alstair, looks interesting. Very good video as well, clear and to the point.
      Not easy to put a professional looking video together.
      Not only that but clicking on his link (The King of Random) opens up a whole other world of interesting projects to keep me and the nieghborhood kids amused.
      Home, down in the valley behind the Red Angus
      Bad Decisions Make Good Stories​

      Location: British Columbia


      • #4
        I've seen that before, and it looks simple to build and useful. It's better to use DC, but it would require some huge rectifiers to get the 1000-2000 amps that this probably puts put, and two turns on a MOT is probably only 2-4 volts, so a silicon bridge rectifier would drop about half that. But there are advantages to DC:
        Paul , P S Technology, Inc. and MrTibbs
        USA Maryland 21030


        • #5
          Most typical spot welders are AC, aren't they?


          • #6
            They probably are. The $170 Harbor Freight version is just a transformer and switch:


            Some of the larger industrial and professional types use a higher frequency than the mains, in order to make the transformer smaller and lighter. The higher frequency current through the weld might improve quality, but I don't know for sure.
            Paul , P S Technology, Inc. and MrTibbs
            USA Maryland 21030


            • #7
              There is a microwave in the snowbank outside...


              • #8
                I built one several years ago, and it works great. Did not use the timer. Just a foot operated micro switch. Nice thing is you can build the welding tips for what ever your need is.
                Gary Davison
                Tarkio, Mo.


                • #9
                  Originally posted by vpt View Post
                  There is a microwave in the snowbank outside...
                  And the longer it sits there, the more it looks like a spot welder...


                  • #10
                    I tried doing that hack .. and had a heck of a time getting the xformer apart. Actually
                    ruined it trying.
                    John Titor, when are you.


                    • #11
                      Originally posted by alanganes View Post
                      and the longer it sits there, the more it looks like a spot welder...

                      Last edited by rdfeil; 02-21-2015, 11:01 PM.

                      Happily working on my second million Gave up on the first


                      • #12
                        There's a bit more to a spotwelder than it seems.... as the crappy non-welds he got clearly show.

                        If there was actually a "weld", there should have been no way to break the washers apart. There should have been a "nugget" of melted-together metal at the weld, fusing the washers so that they would have to be broken through to separate any part of one from the next.

                        Now, the washers appeared to be zinc plated, which would affect the weld somewhat, but I think there should still have been an actual weld, which there evidently was not.

                        With a decent spotwelder, such as even the HF 120V unit, you can easily spot-weld steel together in a virtually unbreakable bond. The process only slightly resembles that "science project toy". It takes under a second, usually.

                        I have even done spot welds in 0.030 aluminum using an HF 120V welder, on a low volume production basis. That was to do 8 welds per each aluminum cover for a custom VFD supplied to the Navy. We worked out the tong pressure, and the timing, used a time-delay relay to set the pulse length, and did quite well with it. Every "X" number of welds, we did a coupon and checked to verify the way it broke when pulled apart.

                        That "gizmo" might weld something, but not much.

                        Keep eye on ball.
                        Hashim Khan


                        • #13
                          Thanks Alistair. I like some of his other vids also. He didnt show how he modified the transformer. Like how to split it to remove the secondary and install the new secondary. But I like the fast paced wordage he uses, prolly post added.

                          Umm re: the HF spot welders?? I have one, the 220vac unit. I did a review of it and posted my opinion here, was a few years ago. Its a great welder, specially for the money. And like Jerry said, it should not be-able to be broken, the weld. With mine the base metal rips before the weld comes apart.

                          I dont think a lack of power was the issue with his washers, the unit obviously has the ummph to melt the washers. I think the zinc coating caused the "adhesion" issues. He clearly shows the transformer has the ability to completely melt the washers if need be.

                          I like this guys post editing of his vids. Not alot of dead time. Im subscribed JR

                          Found my review of the HF welder if interested --->
                          Last edited by JRouche; 02-22-2015, 12:15 AM.
                          My old yahoo group. Bridgeport Mill Group



                          • #14
                            The only DC spot welders are capacitive discharge. I use one to weld the filaments for my SEM.

                            Capacitive discharge spot welder by macona, on Flickr


                            • #15
                              Regarding the transformers- no need to take them apart. The secondary is physically separated from the primary, and can just be cut apart and knocked out. Knock the shunts out also, then thread the welding wire through. It's only two turns or so.
                              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-