Rust removal

[BonnetJizz]

I have an 82 Tf sl/x with pretty bad rust under the front quarters on the bottom left closest to the door... i have allready got at this with the angle grinder and can get a fare bit of it back to bare metal... does anyone no of a good quality rust convertor to use b4 i prime the metal.. ive brought and tried septone but it doesnt exactly work how its meant to.. any input on what i should do.. and if i was to cut the metal out what would be the cheapest option to weld new metal on and what woudl be the best metal to use... i allready no of using a Mig welder but they are pretty expensive. I dont want to prime it then have rust coming through primer after a couple of months.. shes sitting outside till i get my licensce and its pretty much rusting day by day

any help would b appreciated

thanks

[zzz]

get a die grinder get every spec of rust and that includes
the little specs which are really deep to get you may go
through the metal if so get som 2part fibre glass
glass it then bog it then prime it
hope this helps