On Wednesday, 21 December 2016 20:06:24 UTC, Mike Perkins wrote:
On 21/12/2016 10:55, Chris Green wrote:
harry wrote:
On Tuesday, 20 December 2016 22:58:30 UTC, Mike Perkins wrote:
Having never used these before and having to de-rust a large steel plate
with modest pits, what is the most suitable grit size I should use?

This is for a 4.5" / 115mm angle grinder.

I also got the impression the finer grit sized wheels last longer?

Can anyone assist with pros and cons?

Wearing out is not an issue with flap wheels, they seem to go on forever.
They work well, fast and leave the metal with a "bright" finish but also
leave the surface with a rough "adzed" finish".
You can't get into corners and crevices with them.

A wire "cup brush" is bit better in corners but doesn't leave a bright
finish. It gets the surface rust off but the metal is left with a sort
of brown film. Needs "Kurerust" or similar treatment prior to painting.

Yes, I think I'd go with a wire brush for rust removal in general.

Most two-pack epoxy paint suppliers suggest that wire-brushing is more
likely to polish rust than remove it.

In the past I have used wire brush attachments and I am inclined to
agree with this observation.

My instinct is that a flap wheel will be more aggressive with rust?

IMLE a wire wheel removes most rust, but not all, it leaves a layer. OTOH it gets into pits better than sandpaper. So both might be best.


NT