Hugh, I don't want to sound like a know it all... But I know about this
If you do go down the cut off disk route don't be looking directly down on the blade and cut like they do on Orange County Choppers. If it does fly to bits as they often do, it will fly off in the same plane as the rotation. Line up your cut and keep your head to the left of the cutting job. It's just like a chainsaw in this way; let it fly off over your right shoulder.
Have fun and good luck.