Holy cow building a car from scratch takes a lot of this stuff. This is the first game i've ever tried to build a car. I'm scrounging every house for light disposable batteries to craft the rods. Fortunately most houses have at least one in a flashlight. Is there another good reliable source for welding rods or wire?
Brazing rods are currently the easiest to make, just melt down every piece of copper you can find from homes (pots, washing machine internals, sinks, toilets, baths), alloy it with aluminum from rooftop gutters, and sprinkle in some detergent. EZ
With fences being transformed into mild steel, welding wires are tougher to make, but you can bleed acidic zombies and distill their blood into more usable acids for making these. It's also a good way to use lead-acid batteries you otherwise weren't going to use.