Why are my welds inconsistent?

0.15 stacked on 0.15 — you didn't say the gear settings

Gear 85 or above is recommended, weld twice in a row. Fine-tune each parameter to the actual weld result

If I make my own welding pen for the UF20B, what wire gauge (mm²) can I use?

The welding leads aren't up to it — they get seriously hot

I'm on gear 99 — why can't I weld 1.5+1.5?

Hello, under ideal conditions the UF20B can weld 0.15mm copper + nickel-plated, which is the maximum performance of this model in its current configuration. Copper sheds heat extremely fast; we suggest using flux, extending the preheat a bit and fine-tuning the other parameters. Regular battery welding is fully covered. Also, the demo video used a different welding pen (models WP110-6, WP120-6, 16mm² 50cm) with lower internal resistance and stronger current, so welding is easier

Do you need flux? — answered by the creator