Best way to grind higher level mechanics

My mechanics skill is 6. I have the DIY Compendium and according to the item browser I won’t be able to craft the welding rig until mechanics 8. What’s the best way to grind from 6 to 8 that won’t require a bazzilion batteries playing with a makeshift welder?

From a technical standpoint do you have access to either battery compartment mods (the ones that let you load car batteries) or ups conversion mods and charging stations. A vehicle will of course be needed. Other than that the only thing I can think of is if you can craft any of the makeshift guns (but that requires gun skills which you might not have).

I also use battery compartment mods. If you can get a single solar panel on your car you can install every car battery you find on it and swap them out whenever one gets full. Easy and effective.

I always got my late end mechanics xp from tearing apart armored vehicles for components for my deathmobile.

Turns out that making a “simple flamethrower” will get you from 6 to 8 with no batteries