hi, i got a 79 cutlass ive been working on, it was in an accident then sat for 10 years and got extremly rusty. i fix the front of the car that was in the accident, but the back half of the car is rusty. the surface rust came off good from just sanding it to bare metal. theres a lot of rust that i cant seem to get up though. i started on on the trunk, all the surface rust came up, but in some parts the metal is black(idk what thats called), and i cant sand that off. I was using 150 but it wasnt doing much of anything so then i started using 100 and it did seem to help get it off much, any ideas?
heres some pic so u can get a better idea of what im working with:
car sat like this for 10 years in the sun:
After I fixed the front a month ago mysef
(ready to get a real paint job, thats just my prime spray paint job temporarily, lol)
All the rust im trying to remove
(other side of car still looks good with no rust for some reason, idk)
any ideas on how to get this off easier would be nice, kinda sick of sanding for hours with not much of results