Wheel arch rust

[Twigs]

Had some rust over back arches so sanded them back to the metal, primered and top coated it but its started bubbling again. Do you need to treat the insides of the arches with something to stop this happening again?
Cheers
Twigs

 

[Final Maxim]

what did you sand with?

if im honest, once rust has started you cant get rid of it unless you cut out a section or if its just surface rust grind it all away. sanding and filling just delays the inevitable of more rust.

how bad isit? if it aint bad then grind it all back to shiny bare metal with a grinder, then fill over that. if theres any holes then grind out all the rust then fibreglass it and fill.

you can use "rust treatment" stuff but tbh it dont do bugger all.

 

[R80HXX]

if you leave any pitted holes in the metal after youve been at it if the grinder then it will always come back,rust eater stuff is crap,disney work.