Switching low AC voltage, high current (spot welding) - with arduino

Hi there! I'd like to ask a question about switching low AC voltage, high current for the purpose of making a DIY spot welder - based on an arduino for controlling the switching times/current monitoring and limiting, and things like that.

I notice the availability of solid state relays that switch AC voltages. But the minimum AC voltage to be switched appears to be around 24V AC (in general).

Anyone know if there are off-the-shelf, relatively inexpensive solid state relays that can switch 4 Volt AC and high current for potential spot welding applications? So far, I haven't yet managed to find one on the internet.

If there aren't any, then has anybody made their own spot welder that switches low voltage AC? What method did you use?

Thanks all!

[update - I'm thinking that those solid state relays probably can't handle the high currents needed for spot welding, so probably going down the wrong path here.]

It is going to be far easier to switch the primary supply to your welding transformer, where the voltage is higher, and the current lower.

JohnLincoln:
It is going to be far easier to switch the primary supply to your welding transformer, where the voltage is higher, and the current lower.

Thanks John! I'll try that - switching the primary side.

Did you search the forums for "spot welder"?

Paul

Paul_KD7HB:
Did you search the forums for "spot welder"?
Paul

I did search Paul. But there appears to be a lack of detail about DIY spot welders that not only switches the AC using an off-the-shelf solid state relay, but also monitors and limits the current, and controls the duration of the applied AC - like applying two strikes of momentary (pulse) of AC signal.