What would the best way about sanding down surface rust on the body of a car?

 

80 grit sand paper and treat it wth phosphoric acid for all the piting and an acid etch primer!

 

where can you get phosphoric acid and what exactly does it do?

 

they carry it home depot it kills the rust basically. a brand name is ospho maybe that might ring a bell?i dont know if they carry ospho at the home depot! it treats the metal and gives the proper tooth for the paint

 

And use a rubber flexible sanding block for the flat surfaces, and your hands for the corners and ridges. Or, if you are going to do the whole car, then consider media/bead blasting. There is also a product called soda blasting. Seems to work great, and there is no risk of warping the metal.

 

what about bad rust? If I put the acid on the rusty holes and stuff with it eat up all the rust?

 

need to grind it out then treat it with the acid! also look in to por15 its a rust encapuslator it work great

 

Yeah, I was gonna say Por 15.

 

If the rust has made a hole, then it will have to be fixed. If it is big enough, new metal must be welded in. If it is only a pit, then use a dremel to grind out the rust before using POR 15.

 

u can use por15(silver) and fiberglass mat to fix rust holes the company told me its some strong stuff but well worth the money!