Cleaning off rust

[Miggy Mark]

Hello,
It's been 30 years since I welded any patches on a car. Tomorrow I will be cutting off half a sill which has rotted out at the bottom. The back half of the sill, B pillar area to rear arch is solid but slightly crusty. I was wondering what would be the best for cleaning up loose rust on the parts I'm not going to be welding. These day's there seem to be sanding flap discs available or discs which look a bit more like scouring pads. What would people suggest for general cleaning back before Hydrate 80 treatment and undersealing of that part of the sill I'm not welding.

Thanks for any advice
Mark

 

[BrokenBiker]

Knotted wire brush in a grinder for the heavier stuff, bristle wire brush in grinder or drill for light bits and tighter areas

 

[Miggy Mark]

Thanks I'll get those.

I forgot to ask, I also need to sand off the galvanised part on the replacement sill I've bought before welding and the sand off the paint on the part of the existing sill I'm welding onto. Would that need a flap disc? If so what grit to avoid removing metal along with the paint and galvanising.
Thanks
Mark

 

[steveo3002]

i use the poly strip wheels to clean off paint /rust /glav , once its cleaned up you might want an abrasive wheel on the rust pits

bonus is they dont hardly touch the metal so no thinning or grinder marks

 

[MetalMonkey]

Blasting is usually the best option, where that isn't possible I'll use a combination of needle scaler, wire knot wheels, sanding discs/sandpaper, even die grinders to get in small spaces.
The main problem with sanding and wire wheels is they tend to "polish" up the surface without digging down into the rust.

 

[steveo3002]

was looking at those bristle blasters , look effective but why are they best part of £1000 , fancy wire wheel on a grinder body?

 

[BrokenBiker]

Poly discs get another vote from me for galv, I buy them in bulk and use them for paint, galv and occasionally finishing welds I've polished down to smooth everything out

 

[CompoSimmonite]

If you have a full sill then, personally, I'd fit the whole item rather than just the front and dealing with a rusty rear