Quarry dust

[MDE]

Has anyone tried using limestone quarry dust instead of sharp sand in coarse lime plaster? I have access to a supply that is much cheaper than the sand I can get - it is available either as a dust or grit (a mixture of 2:1 dust to grit makes quite a usable substitute for the sand). It seems to mix up alright - I'm just wondering about how it might work out in the long term.

 

[Lime]

I can't think of anything to suggest you don't use the dust or grit.
There would not be a great deal of difference in strength between sand and limestone grit mortar.
Chemically I don't think you have anything to be concerned about.
I suspect there will be some areas where one is better than the other, particularly in relation to matching other mortar, but as a plaster or mortar limestone particles may even be better as it would be more homogeneous with lime compared to sand.

 

[biffvernon]

There would not be a great deal of difference in strength between sand and limestone grit mortar.

Not relevant to domestic brick-laying or plastering jobs, and being a bit pedantic, but for mortars that need to withstand heavy loads or wear such as structural concrete and road surfaces, the rather great difference in strength between sand and limestone could prove disastrous.

But yes, you'll be fine using quarry dust.

 

[MDE]

Thanks for the replies. I'll let you know how it works out.