rtbcomp
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No - You must NOT have one wire connected to the workpiece, each wire goes to an electrode.
- Thread starter GeorgeB
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No - You must NOT have one wire connected to the workpiece, each wire goes to an electrode.
I agree it wouldn't be ideal. It wouldn't produce a 'proper' spot welder as illustrated in Graffian's diagram. But it wouldn't actually be much different to the crude Kelarc 'spot welder' which earth's one side, effectively. It should still produce heat, a spark and signs of 'energy'.
Terry - posting photos here should be quite straightforward. There are guides/tutorials somewhere. Give it a try. It's no more difficult than sending photos by email.
rtbcomp
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Instructions how to post photos appears here
http://www.mig-welding.co.uk/forum/showthread.php?t=5016
If you are using "Quick Reply" you will need to push the "Go Advanced" button.
http://www.mig-welding.co.uk/forum/showthread.php?t=5016
If you are using "Quick Reply" you will need to push the "Go Advanced" button.
If my experiments are anything to go by, you won't need much pressure at all in order to ascertain whether you have enough current/power to melt steel and stand any chance of making a spot weld. My first spot weld was formed using virtually no pressure and was still quite strong.
I see spot pressure as sort of stage 2 - the icing on the cake - once your electrodes have the power to melt steel in the first place.
Can you provide clearer photos of your transformer and windings, please?
Terry - so is that 7 windings of thick black wire on the left and thousands of original windings for the mains input on the right? I can't see the primary winding very well but does it appear to contain thousands of turns of relatively thin wire? And it was definitely the primary winding originally, was it? If so, it looks good. 7 windings may be a few too many but I'm only talking about fine tuning. Perhaps 3 or 4 turns would be better but, either way it should produce low voltage and high current. I simply can't fathom how you could get over 600v out of seven windings!
graffian
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If your input voltage was 100v and you got 600v on the seccondry that's 6:1.
so it would suggest, if you had 6 turns in the secondry, that you had 1 turn in the primary! Or am I a complete plank. In which case I can understand why it blew fuses.
You need the arms fixed in a clamp, you need pressure and the tips have to align. I wouldn't bother trying car repairs with it, even if you get it working. The bits I pictured were stainless and they welded a lot better than steel.
so it would suggest, if you had 6 turns in the secondry, that you had 1 turn in the primary! Or am I a complete plank. In which case I can understand why it blew fuses.
You need the arms fixed in a clamp, you need pressure and the tips have to align. I wouldn't bother trying car repairs with it, even if you get it working. The bits I pictured were stainless and they welded a lot better than steel.
rtbcomp
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Me neither, if he'd got the original primary & secondary mixed up he would get less, not more, volts on his new secondary.
Looking at a microwave transformer the primary has hundreds of turns of thickish wire, the secondary is thousands of very thin wire.
670 mV would be nearer the mark.
Terry - if you look back at my post #1 at the start of this thread, you'll see that my arc welder transformer is quite similar to the one you have so, yes, I'd say it should work to produce some sort of spot weld. I never got as far as producing a spot weld which I considered strong enough for a car, though.
