Have stripped back all the flaky rust with one of those 3m paint and rust stripper disc things, which are truely awesome, entire bonnet of the car is coated in rust dust.
Now i'm left with a layer of black very hard stuff (rust?) where the flaky rust was. The paint stripper disc didn't even touch this stuff, and it laughs at 80 grit carbide paper, so I figure I have to go chemical on its ass to get a result.
It looks a lot like this..
![Image](http://i1223.photobucket.com/albums/dd518/Grrrrrrr_11111/IMG_20111227_102102.jpg)
So is there anything that will work, other than an angle grinder
and a welder?