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Well, I am going to attempt to make a spot welder that can join two 1.2mm bits of stainless sheet together. Lets get started.

First things first, the tools! My awesome makita 18v battery drill and it's rather odd brother, and some hand tools, very handy yup.

Step 1: Prep your tranny


There are a slew of microwave oven transformer instructables out now, so really I shouldn't bother with this eh? Nahh, I did it this way ...

Notes on the pics.
test 1 =&gt; http://www.youtube.com/watch?v=PB5HJszRBOg <br> <br>test 2 =&gt; http://www.youtube.com/watch?v=EoTtf84V23k <br> <br>doesn't work. Please, can you re-upload ? Tnx
I'm working on it. I've got a fair bit on at the moment, so everything is going at a snails pace while tougher aspects of looking for a new house are being dealt with.
the videos were removed by user
Oops, I forgot about these links. I'll see if I can find them and reupload, if not I'll just have to make a vid of the welder making random noises and sparks
I am making a spot welder just like yours but do you have to use a ballast or just hook it up to the mains? <br> <br>Thanks.
I've changed the internals of the box a little bit to include a 6amp circuit breaker just in case anything goes a bit wobbly, but apart from that I've got the lead connected straight to the primary of the transformer.<br><br>The wee beast works pretty well. I have to replace the current bolts (electrodes) with copper though, because they heat up too much and end up sticking to my work sometimes.
Thanks for the replie, i have made my spot welder on the weekend including a emf filter and a 10amp circuit breaker. I did try to weld thin tin cans and my brass bolts (electrodes) stick to my work too its imposible to get the work off the bolts with out breaking the weld, it also rips a tiny part of the brass off on to my work. <br> <br>I am wondering if i could use a harder brass for the electrodes or i could use copper, but i dont know how i could make electrodes out of copper? <br> <br>
When I was using it it didn't take long to heat up 1mm stainless steel sheet and bond 2 together. Those tin cans are pretty thin so it might just be a case of closing the jaws for a shorter amount of time. <br> <br>A better idea might be to put a push button in that energises the primary coil when pressed, that way you can clamp your work into the jaws and press the button really fast. The weld would end up in the right place, and with a bit of practice you can judge just how long to hold the button down. I might give that a go actually. <br> <br>Have you filed your bolt ends to rounded points where they touch your work piece? That will make a difference. Post some pictures, let us see!
I cant post any photos at the moment as the welder is in bits every where but i will soon, any way, im using the wall swich to turn on and off the welder and the brass bolts are not rounded at the end. <br> <br>My brass bolts glow read hot at only about 10 seconds into the weld and i put the arm down before i power it on and pull it up after it is off. If i go any lower than 10 seconds it does not weld thin can. <br> <br>The voltage coming of the secondary is about 1.5volts no load if that helps. <br> <br>Thanks.
Oh sorry, <br> <br>Do i have to remove those seperators inbetwen the primary and secondary coil
Too much heat. What you're aiming for is to heat your work just past the melting point, but only juuust past. If those bolts are glowing and the tin isn't melted together you might need thicker bolts to let more current pass. <br> <br>Don't bother removing the separators for now, sounds like there is plenty of current there already. <br> <br>My thoughts about the intended function of the welder is to send high current to the work through a low resistance path. The resistance of the work is what creates the heat to weld the pieces together. Rounding the ends of the bolts will give a smaller 'pinch point' which will increase the heating effect on whatever you have clamped in there, it should also reduce the stress on all but the tips of your bolts too. <br> <br>
Nice work - I watched the testing videos. Wish I had a clamp meter...
I must admit, mine is a fairly cheap one. But seeing as I usually only work on residential up to medium machinery the 400Amp range is quite ample for my needs.<br><br>For some really nice meters check out Fluke ones. Or for a big selection try http://www.multimeterwarehouse.com/clampmeter.htm
Hmm, a lot cheaper than I thought they were, but in entirely the wrong country! I've actually started wondering how easy it would be to make a clamp meter probe for my standard multimeter. *Thinks* surely I can just put a winding on a ferrite core for this....
Dude, don't worry about which country anything is in now! The interweb has freed us of all those restrictions *dance*<br><br>To make your own clamp meter you'd need to be pretty good with transformer calculations, or at least have some steady current drains you can calibrate your measurements with. <br><br>If you used a ferrite core there may be the problem that once installed as a current transformer you'd have to leave it in place, or pull apart your wiring to get it back. Have a look at this page under 'Wound Primary CTs'<br><br>http://www.itl-uk.com/introduction-metering-transformers.html
Actually found some perfectly adequate clamp meters on eBay very cheap - perfectly adequate for my very occasional and not very accurate needs! Interesting web page - I once read a book about transformer design (about 20 years ago) and realised it was something I was never going to do simply because I didn't know where to get a core with appropriate known qualities to work out the primary turns - for me it was always going to be knowing the basic ratio and thinking of a number for the primary turns - not at all satisfactory.
Haha I love Photonicinduction and alll the stuff he dose

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