Spot burst. In spot welding. How can I avoid it?

[vicens]

I would like to know if it is possible to avoid the blast of the point.

My welder is a jp welder. My 12V 70ah battery.

You can see the bursting point.

You can see the tips of the welder. The problem is the one on the left side.

 

[redilast]

Uneven electrode pressure. Accidentally touching electrodes together, poor welding surface (e.g. welding right near the outer edge of a batteries + or right on the edge of a tab). Beyond that, maybe your welder is randomly putting out too much power for some welds. I've had this happen a lot, but usually I can tell that it was my mistake. Now it only happens once every few hundred welds, but it used to happen a lot more.

 

[kdog]

3main reasons in my experience.

-Uneven pressure

-Crud on electrode tips ( give them a quick sand every 30-50 welds with fine grit to prevent blowouts, reshape if necessary after a blowout)

-Poor contact between nickel and battery. This is from bends/creases in the nickel or it not sitting evenly. The current path is suddenly halved resulting in metal vaporising and an arc that can blow right through the battery.

 

[vicens]

Thanks for the advice
The bursting point have been reduced almost to zero.