rust on stucco

any tips on chemical to use to remove rust from stucco? have used rust remover from home depo. need a cheaper gallon mixture. is it muratic acid?>?

if you had any HF [hydrofloric acid] based alum brightner and a high alk. based soap then you could 2 step it.
im quite sure it will work.
Oxalic acid is much safer and it by itself might do the trick.
These acid's are not as harsh to the stucco as muratic.
muratic eat's lime.

Oxalic would be my choice also. I like it for just this reason, it is both a good wood brightener and rust remover.

I use phosphoric acid @ 30 - 40% to remove rust. It is what is mostly used in commercial rust removers it turns the rust into iron diphosphide that is also impermeable to water and you can paint over it as well.

Ron, I two stepped the other day on a rusty tipper it got it clean but the rust is back I used 2% HF on it , maybe the HF doesn't give it the protective film like Phosporhic acid does.

Muriatic or Hydrochloric as it is also called will cause rust. DON'T use it to remove rust it will create more problems!

If this is really dryvit, not stucco, go to the dryvit site. It will tell you to use sureclean 600, which is muratic acid based.