So i want to paint under seal on my fiesta on the sills only, some rust spots but no holes will i be ok to paint this over rust spots under a quick sand down or will this make the rust worse? advise please.

 

Rub the rust down and apply this first before your underseal
http://www.ebay.co.uk/itm/Granville-...AAAOSw3ydVthem

and inside the sill squirt some of this inside <make sure you get the extension nozzle
http://www.ebay.co.uk/itm/2-x-DINITR...sAAOSwtnpXoFa7

 

thanks for your reply, this is the stuff i have already bought . http://www.halfords.com/motoring/pai...body-seal-2-5l

 

that is real good stuff as all hammerite stuff is but to worn you it will remain tacky and you can only apply it to areas you can get to, where as a spray might be better.

 

Waxoyl is ok, it does the job by holding back any rust and has a creeping action. Stays tacky as said above.

Better to rub down, treat, prime, sprayable sealer, then paint. Appreciate that not everyone will be able to use sprayable sealer as you need a compressor.

The sealer is from 3M.

 

so from sounds of it better to do full works on it like i did with my wheel arches after i fibre glassed them, i was hoping i could just paint this stuff on top of the rust under the car to stop it getting anyworse but that would make it look worse and the rust could still break through again in the future?