I'm not sure what the question is Nell. I doubt that the ringing is from a hollow more likely that the stone is a mix.

Thanks, inkognito, for the opinion on the ringing. I'm sorry my questions are not clear. Let me rephrase my need regarding stone.

In the Stony Silence thread, RockHewer offered to give tips on working stone. He suggested that we start a new thread. This is the new thread.

I am open to suggestions for working with this rock to make a shallow depression suitable for a birdbath using simple methods or more sophisticated tools.

RockHewer has already explained that he does not visit the forum regularly. There is no rush to do this project while the daytime temperatures here are in triple digits. The birds have a constant, adequate supply of clean fresh water right now. Thanks.

Nell

So my suggestion would be to clean it up using a pressure washer and when you can see an obvious direction for water to pass over the rock go with the flow.

Ah. I never thought of dragging out a pressure washer when a brass nozzle with just regular pump pressure didn't make much of an impression.

Maybe soon. It's only 99 degrees this afternoon as clouds roll in.

Thank you, Ink.

Nell

rent a concrete saw, kinda like a chainsaw only with a circular blade. Use it like a grinder and keep moving around in a circle as the blade cuts and create a bowl. I used one before, they are easy to use. I gurantee it will be very messy and loud though (-:

Another thing you can do is rent an electric hammer drill, or the electric version of an air hammer. these work very nicely for "bowling out" a rock for things such as a bird bath. The concrete saw along with the electric hammer would make the job pretty simple.

Thanks for the tips, bonecarver and timscott. Every little bit helps. I've discovered that we have a pneumatic hammer here, and many chisels and rasps and drills. There are also some grinders that I think might be helpful, too. All this comes after the pressure washer gets all that sandy stuff out of the way.

Now to work out the safety issues before I start instead of after somebody gets hurt.

Thanks again. As my DGS once said, "I'm sinking a plan."

Nell

Hi Nell,
I know its a little late,we do this for a living, first the hollow sound could be an instability in your stone, rocks from various areas do occasionally have rotten or soft spots, you should also look for fractures which may be inclined to breakage,,
For carving we rarely use the pneumatic hammer, we also rarely use the hand tools, we fire up the sthil saw which is used for masonry as well as concrete work, you need to make sure the blade is for stone,,small slices and a hammer and chisel will make short work out of this,, to finish it however a small grinder with a good diamond blad helps, then we follow up with a torch popping and flaming all the marks out,,
hope this helps
GB