Frame Repair - Help Please!

[ArcherV20]

I'm planning to cut and weld up my frame because there is some rusting going on down there. The welder going to be used needs to be grounded to the car itself in order to start welding, my question is - does the current run through the gas tank? How dangerous is this? I'm also having trouble getting more clearance, we have no access to a hoist, anyone know how to raise the car the most? My jack will not lift it high enough, we need about a foot and a half. Also any tips on this job.

Thanks guys.

[180fan]

Grounding through the chassis will be fine. The gas tank is still connected to the car and is made of metal and the chassis is used as a ground all day long so don't sweat it.

A foot and a half of clearance, consider calling a few shops if they will let you use their lift to get this work done or pick up a 3+ ton jack and 6 ton jack stands.