Hi There, regarding the cutting of a thin silicone adhesive layer to free a sundial. I don't think that a thin plain wire would do the job as silicone is more tenacious than cheese. Further I don't think that the use of a wire saw as used by campers (or a diamond dust swa) is advisable as it could damage the dial, (these type of saw are not reknowned or indeed intended for accuracy).
However I saw (no pun intended) a repairman remove a windscreen (windshield?) from my car which was bonded on with an adhesive similar to silicone. He used a length of thin multistrand, twisted brass wire which we can get in the UK for hanging pictures in frames, I think it is probably universally available. The wire was attached to a ring at each end for gripping (perhaps 11/2" diameter curtain rings or those rings used for keys). The inherent twist of the wire gives a texture which will cut adhesives such as silicone but the wire is soft enough not to cause damage to harder components such as hard engraving brass dials (or windscreen glass). Best of all such a device costs only a few pence to make and is simple and quick to use. Hope this may be of use to someone. Regards Terry Get your own zoom email - click here - http://www.zoom.co.uk/
