Consensus on Fixed Spot Welder Contacts?

HI - searched around, but could not find a definitive answer. Are fixed contacts for a spot welder usable? That is, by fixed I mean both contacts are rigidly mounted to the same mechanical structure, and it is up to the operator to ensure even and adequate pressure. The option is either a spring balancing method are two independents contacts, one in each hand.

As I see it:
Fixed: pro is shortest wring possible, hence less losses in wires. Simple to construct. No inadvertent shorting of tips. Con is requires operator to carefully place contacts, and monitor connection quality, fixed spot spacing.

Independent: Pro is simple to set up, easy to control, allows any spot spacing. Con is requires both hands, no spare hand to hold the pack, trigger welder, etc., and longer wires.

Spring mounted: Pro is reputability of welds, can be semi automated. Con is difficulty of implementation, length of wires, and fixed spot spacing.

Your thoughts?

Thanks
John

I'm not sure if I understand the question.

Broadly speaking when I spring mount right next to the weld I get hot creamy welds and when I spring mount too far or on a separate piece I can get unevenness in the weld, little spatters or uneven diameter (too hot in one spot too cold in another?)

Ultimately whether you hard anchor or just spring mount will be down to how good of an arc you can get.

Hi

Some of the DIY welders have two probes, you hold one in each hand, ensure proper spacing and proper pressure in each hand, then hit the footswitch. Bang, weld

Others look more like a traditional spot welder, with two arms which hold the two contacts at a fixed spacing, and spring tension (or other means built into the welder) ensures both contacts have the same pressure.

An alternative is a single hand held probe which holds the two contacts at a fixed spacing. The operator must carefully hold this against the nickel to ensure even pressure, and press the right amount. While likelihood of sub-optimal weld is higher, this method frees one hand to hold the battery pack, or hold a beer, whatever.

I am now leaning towards a more detailed device which incorporates springs to allow even pressure and fixed contacts.

Having both probes sprung seems like it would work fine. However (if I understand your concerns) perhaps consider having one probe tip being fixed, and the second probe sprung. Such an arrangement would have a consistent and even pressure under each probe tip, even if the hand/eye alignment of the probes from one cell to the next varied a bit.

Pic is originally from lewtwo, but now slightly modified.