I once saw someone do this in a book, they made a bowl in a stone.

Get circular saw with a masonry blade. Cut lots of grooves parallel to each other just 1/8 inch apart. Use a chisel to tap out the remaining skinny wedges and smooth the bottom.

Using a blade to make the bowl deeper is a great tip. Here where I live, we have two different types of blades to cut with. A masonry blade is a type of blade that looks like a metal cutting blade. That is, it's a blade that has the grit throughout the whole blade and wears away as the cutting is done and is meant for softer brick.

A DIAMOND blade is what you want to use however because of the hardness of the basalt. It's a blade that has diamonds electroplated to just the outer rim. They can be had relatively cheap. They come in sizes to fit a circular saw or 4-5" angle grinders. There are two types of these also. Segmented and continous rim diamonds. You'll see the difference immediately.

I recommend the continous rim.(Dry cutting type not a wet tile blade) I still have a mark on my lower chest from where a segment came off a blade as I was cutting stone and it hit me like a bullet. It went through a heavy shop apron. a shirt and an undershirt.

I'd also recommend using an angle grinder as your tool to do this. You'll have more control of the tool. Have the guard and handle on the grinder. Wear safety glasses and a good quality dust mask. This procedure makes a huge amount of dust thats very dangerous to your lungs.

Use the grinder like a circular saw and make many narrow kerf cuts as gottagarden said. Go slow and let the blade do the cutting, DON'T force it. You can knock them out with a hammer and chisel, then you can turn the grinder flat (like a grinder is supposed to be used) and use the blade that way to smooth the stone also. You'll wear they blade out quicker this way but it's still the cheapest & fastest way to do it.

I have years of stone shop experience (my screen name comes from this) and this is a relatively easy way to do this. If you have more questions and I'll help you any way I can. Good luck.

Oh jeez. Circular saws with diamond blades, angle grinders, now I'm intimidated. The only power tools I've used so far are a drill and a stapler and I could be wrong, but this doesn't seem like the kind of project to cut my teeth on.

I was Googling around for ideas and information about it last night & came across a picture similar to what I'm looking for (link below). It's a different kind of rock, but the circular basins look like they were ground out with some kind of cylindrical tool. What would it be, and do rockeries have them, and would they do the job for me?

Kristin

Here is a link that might be useful: stones with ground-out bowls

GnD, Those stones with the basins are a pumice type stone. Very light weight stuff. Those were probably done on a cnc router with carbide tipped bits with lots of water to keep things cool and the waste washed away. You can do harder stones (like your basalt) with diamond tipped bits and plenty of water with a cnc router LOL Now you're talking industral stuff....

Yes, certain stone shops would have the tools to do that. Basalt is a stone that will require diamond tools to work it. Got any guy friends with power tools? What I described is a very simple way to make the basin deeper.

Is your column easy to move? You could call some places that do headstones and see if they do it for you. Lots cheaper to take it to them than have them come to you.

Yeah, I can move it, I rolled it out of the car and into my garden after we bought it. It's only about a foot square. I'll check out headstone places, thanks. I have girlfriends with power tools, and lord knows I'm not usually timid about trying new stuff, but I don't wanna mess up my rock! LOL!

Can you make a guess how expensive a job it would be?

Thanks,
Kristin

GnD, No I'd have no idea what they would charge you for such a job. You'll just have to call and see if they'll even try it.

Be VERY exact in your description of what you have and what you want done. Take a picture around to some shops (much easier than the whole stone) and that will give them a better idea of what you want and the cost. Good luck.

Someone with a sandblaster can do the job in about 10 minutes, Same way they cut letters in a headstone nowdays.

Sandblasting is an excellent suggestion. I doubt a home type blaster would have the power to do this quickly. It would also leave large amounts on sand to clean up at home. You could take the column to someone who has a more industrial blaster setup to get it done quickly and avoid the cleanup.

Sandblasting produces huge amounts of dust that are highly injurious to your lungs. You need very good protection to avoid problems if attempting at home too.

Where did you get the column in the first place?

If you bought it at a stoneyard, you might want to check with them first. Or try other stoneyards in your area, especially ones that advertise themselves as specializing in "decorative rock" or "landscaping stone" or the like.

I know that here in Portland, a number of the stoneyards will drill holes for fountains or grind basins for birdbaths in the rock that they sell for a not-exhorbitant extra fee. I'm sure that any place that offers such a service would also be willing to deepen the basin on your column for a reasonable sum, if you brought it in to them.

I don't blame you for being intimidated, BTW! The descriptions of the process and equipment involved had me feeling a tad nervous myself!

Sorry if the description of grinding the stone intimidated anyone. But that was her question and I just answered it. It really is simple. If you can use those same tools for woodworking you can use them for stoneworking too. It's just a matter of different type blades and how to handle the tools safely in the first place.

I've been handworking stone 18 years and I am hoping to get more people interested and actually involved in doing it. It can be a great hobby just like anything else. It does require a bit more in the way of safety measures and it is a heavy medium to work in but all that can be dealt with if the will is there.

All hobbys have their own set of issues to deal with, especially health related ones. The woodworking forums/sites all stress dust safety now too. Lots of woodworkers are discovering too late the problems they ignored about dust. Stone working is the same. Just be careful of the dust with ANY hobby.

So maybe give it a try. Stone working can be fun!!

Oh, I didn't mean to criticize all the great advice you gave at *all*, rockhewer, far less to dismiss your very generous offer of further help. I was just commiserating with the OP - kind of a "don't worry - I don't think you'll sound like a wuss if you decide that you'd rather let a pro handle this job this time" sort of thing. :-)

Like you said - it's a heavy medium and requires correspondingly heavy/industrial equipment, which could present a logistical nightmare in and of itself. And a piece of stone to which one is already emotionally attached is probably not the best choice for a beginner's first project.

I really admire your enthusiasm and willingness to help out, and I'm sorry if I came across as critical.

Avia, Yep thats what I said when she said was unsure about doing it herself, to take it somewhere to have it done.

Your remark about - "it's a heavy medium and requires correspondingly heavy/industrial equipment, which could present a logistical nightmare in and of itself". was partly true of what I said. I also said that the tools to use are woodworking tools and only require a different type of blade. I hope those types of tools aren't too heavy and a logistical nightmare :-) LOL.

It all depends on the size of the projects a person wishes to undertake. Woodworkers, Mechanics or anyone can need bigger shops/tools according to what they want to do in their respective fields. Some folks can get by with a lot less too.

This project would just require an angle grinder($15-$80), diamond blade($5-$25),safety glasses, a good dust mask and about 1 hour of time depending on how much deeper she wanted to make the bowl.

That's the misconception I want to dispell. That it's difficult and requires all different tools. If you have little knowledge of the safe use of standard power tools then don't do it. If however you know how to use standard woodworking tools then you can also do some stone work.

Having someone come to the site and do it can very expensive. Taking the piece somewhere else reqires a lot of moving and presents more chances to damage the piece too. It is just up to the person. I just want to give people another choice.

Sorry to go on so, I guess I have a missionaries zeal to get people over thinking that working with stone is too hard. I cant wait to get my hands on some more glacial boulders and make some pots or birdbaths :) And no you didnt come across as critical. I hope I don't either.