Re: [CAD_CAM_EDM_DRO] A bit off topic - resistance welding

One type of spotwelder is the the pulse type as you are describing, the other type is the very low voltage AC at lots of amps.

I have built a low voltage one. Basically, you need only a volt but hundreds of amps. To get one volt, you only need a turn of two
on a transformer but you need to use "starter cables" for size or an equivalent ribbon conductor.

You might want to try a really big toroid transformer and then run a turn or two through the center.

Bertho Boman
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Ian Wright wrote:

> Hi,
>
> I know this is a bit off topic but I know you lot out there have all the
> expertise in the world!
>
> Does anyone have any idea whether it would be possible to make a simple
> resistance welding set-up for tiny jobs? Basically what I am wanting is a
> way of spot welding bits of watch or small clock mainspring material
> together - spring steel up to about 15 thou thick with welds probably about
> 1.64" diameter. I was thinking it might be possible using just a big power
> supply and capacitor like in EDM and discharge this through some kind of
> 'clip' but I'm not sure how to control the discharge (SCR, Triac?) Also I'm
> not sure about the voltage/current needed - a 24 volt, 10 Amp transformer
> with a bridge rectifier and 10,000uf capacitor seems to give an impressive
> spark but would this be enough to weld my bits of steel or is it only good
> at screwdriver blades? ;o)