Peach Alabaster Bowl, Lathe Turned.

I was going to call this post 'how to turn an alabaster bowl' but really I should be calling it 'how not to turn an alabaster bowl'. It was more of an exercise to find out whether a piece with this many faults can be turned or not. I've carved it by hand before so know that this many faults make the stone very fragile..

Step 1: the hunk of alabaster stone, the grey lines are shale (soft limestone) which breaks easily and is also very abrasive on tools. There is a high risk of it breaking on these lines....

Step 2: glued to an aluminium fitting and a small hole being drilled to support the rear. Because of it's brittle & fragile nature it can't be held in the lathe by normal means but I don't know if the glue will hold. A piece of wood has to be fitted in the hole or the pointy centre of the rear support would fracture it...

Step 3: starting turning... I foolishly made little effort to round the stone 1st and the vibration is massive, at the moment I'm just trying to round it off to see what I have to work with...

The dark grey is where a piece broke away, that was supposed to be the top rim of the bowl but it's too fragile so I had to work on it in reverse. A little dangerous as the cutting angle is now trying to force it away from the glue line, usually u would turn a recess or dovetail on the bottom and then reverse the bowl to work on the inside...

Step 4: a nice shape is now starting to develop and sanding/polishing on the outside can start....

Wetting the stone allows you to see the colours that will show when it's finished...

Step 5: As I feared the glue didn't hold and I've had to use some inventive chucking methods to start on the inside. Here I'm drilling a depth hole/opening which will make starting with a chisel much easier... This is after about 5-6 hours work and the amount of force needed for drilling has caused a small piece to break away from the top so yet more changes will be necessary to the design... I called it a day for today and will come back to it after much needed regrinding of tools....

Before I could continue I had to make a new chisel to undercut the rim. Not very pretty but the solid steel bar adds needed strength..

Placing a light inside shows why it's been used in art for so many millennia.

Trying to open and undercut the rim caused small cracks which broke out, this kept happening until most of the top had broken away and the rim had opened up to a more conventional bowl shape and less of a hollow form...

A lot smaller than it started but as the whole purpose was to see if a piece with this many faults can be turned. It's a little wonder that I managed any bowl from it. Yes it can but it shouldn't!

The grey is the limestone shale which runs through the stone, each patch of grey is considered a fault which would cause this to be discarded by any normal stoneshop...

Notice also the obvious presence of Mica & Quartz crystals