Expert: George Maxwell - 1/8/2008

Question
hello sir,

         please tell me any chemical or acid is useful to drill holes by eating the stone using from the surface of the stone.

                                          thank you.

Answer
Hi, and thank you for your question,
The answer depends on the sort of rock you're using.

Hydrofluoric acid attacks most mineral rocks, but is very toxic, corrosive and reactive.

If the rock is made mostly of  an alkaline compound (e.g. calcium carbonate in Limestone) you can use any sort of acid to corrode it - the stronger the acid, the quicker the action.

It's pretty much impossible to "drill" through rocks with acids however - there's no guarantee that the liquid will follow the path you want it to. Gerenally if you pour an acid over limestone (for example),it spreads out over the top layers and dissolves the rock in "chunks", even if you pour it in to a very neatly defined area at the start.

Hope this helps.