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General Climbing Discussion

Topic Date User

Grafitti on Mirage, Taipan Wall ? 21-Aug-2006 At 3:52:10 PM tmarsh

Message

On 21/08/2006 WM wrote:
>Does anyone know of a good way to clean chalk off? I've seen photos of
>people with water buckets and stiff nylon brushes at centennial glen....does
>this work or does the water just smear the chalk down the rock and make
>it look even worse?

The water and scrubbing brush method is a lot of hard work for not very much result. It doesn't make it smear down the rock face but equally, it doesn't exactly disappear either.

I wonder if there is a chemical that would dissolve magnesium carbonate but would not damage the rock. Any chemists out there have any suggestions?

edit:
I should have googled this before posting. Both hydrochloric and sulphuric acid will dissolve chalk, releasing water and CO2 gas:
MgCO3 + HCl → MgCl2 + CO2 + H2O
or
MgCO3 + H2SO4 → MgSO4 + CO2 + H2O

I'm guessing that the obvious handling difficulties that would arise trying to scrub a rock face with an acid solution coupled with the well known effects of acids on nylon climbing gear would make this a pretty impractical approach. Oh well.