Hand burnt, who knows how many strands blown — today’s main job is swapping the welding-pen sleeving for the braided sleeving the comments recommended. This AWithZ P60F blew up on him twice before, the pen even charred black. Question: is the P60F’s gear 30 the same as the UF20B’s gear 30? In theory gear 30 can weld Jiashikai cells. Try 0.15 nickel strip on the P60F at gear 30: two spots, tear two holes, fine, no different from the UF20B at gear 30; the strip stays on and curls off. The leads all charred black because he carelessly touched other nickel strip while welding; look at that wound, how many strands blown; when your hands are clumsy, never short it. Sleeving: the big one won’t go on (can’t even get a finger in), the slightly smaller one works, feed it from the front, there’s some room inside, so touching something else won’t blow it up any more; the pen that blew up before had who knows how many copper strands blown through, terrifying; after the swap no fear of touching nickel strip — perfect. Then the UF20B’s pair of pens gets the same treatment, a perfect mod. The UF20B at gear 30 on 0.15 nickel strip also tears two holes, very solid; up to gear 40 is harsher, a real tearing effect; a 0.15 nickel base can take 0.1 to 0.15 copper on top. Job done. Comments (87): polyamide / cotton-blend sleeving is softer than nylon (now you tell me); same UF20B at gear 60 on 32140 LiFePO4 is weak (pen upgraded? nickel base first? the parameters were given in a previous video); how thick a nickel-plated strip for a 72V30A e-bike with a 1200W motor (two layers of 0.15 should do, depends on your welder); sleeving spec (triple-weave dense PET braid, flame-retardant nylon 3–60mm anti-vibration snake-skin sleeving, 12mm black / silver, 2m); hand-built capacitor welders are still the real deal; press down firmly and the welds look good with no splatter.