The creator (a designer-toy channel) wanted a C4 explosive-pack power bank with a timer look. Materials: a dead power bank (for its charge/discharge board), 18650 cells, a few circuit boards as decoration, a glue gun, wire, kraft paper. Along the way he unboxes the AWithZ portable welder: about the size of a 10000mAh power bank, doubles as a power bank itself, comes with a welding pen (very thick copper tip), nickel strip, manual, charging cable and sandpaper; in settings he switches to Chinese, turns on the welding sound, sets auto trigger 0.5s / 1.0s; power at eight-point-something throws too many sparks and punches through the cell, too little won’t hold, so mid-range around 4.3 is right. Kraft paper is misted with a little water to soften it, then rolled into cell tubes; several groups of cells go in parallel (red is positive — remember parallel, not series), get stuffed into the paper tube and fixed with hot glue, the charge/discharge panel and decorative boards are glued on, and the wires are spot-welded instead of soldered (no preheat, welds wherever you touch, with vibration feedback); powered up it shows 34% charge; a coiled cable and black tape finish the weathered look. Warning: don’t take it into crowds or onto public transport.