Welder series: AWithZ UF20B with the upgraded No. 6 welding pen, trying gears 1–5; preheat 0, interval 0, (trigger) 1 millisecond; two rolls of nickel-plated steel strip, no idea which is 0.1 and which is 0.12, never mind; welding the 0.1 or 0.12 nickel-plated steel strip onto a Jiashikai negative. Gear 1 result: won’t hold; up a gear, gear 2: gear 1 didn’t stick at all, gear 2 sticks a little; gear 3: sticks a bit tighter again but still peels off; gear 4: a bit hard to peel but still comes off; today up to gear 5: this is the upgraded No. 6 pen, 0.1–0.12 thickness on a Jiashikai negative, gear 5 feels like it might stick a little; that’s the show. 11 comments: wanted to hand-build to save money, good grief, a welder costs a few hundred, just buy a new one (creator: if you want cell performance there’s really no saving money); gears 10–12 for 21700; try a 0.3; either go 4 capacitors or 133 mains-frequency; go do deliveries instead of this (no deliveries to do); is 36V at the port normal on a 48V pack when switched off.