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Decorating Defects - their cause and cure

Putty loosening

When putty loosens from window frames, or from cracks, nail holes, either the material itself or the mode of application is at fault.
Genuine linseed-oil putty should be made from raw linseed oil and whiting, the pro­portion being approximately five parts of the whiting to one of the oil. In the making of inferior putty, linseed-oil" foots," fish oil, mineral oil, and other non-drying oils are sometimes substituted for the pure linseed oil, and although, whiting being cheap enough. it might seem unlikely that any other material would be used in its place, a proportion of barytes is sometimes employed, since it requires less oil to reduce it to paste consistency.
A homely but useful test for suspected putty is to work it in the hands, kneading it well until it is warm, when it should not be difficult to tell, from the characteristic odour, whether linseed oil has been employed. The use of barytes generally produces a short, brittle putty, and this may be tested by pulling the material into lengths and noting any tendency to break.
It is definitely worth while to pay a good price for putty; with material of the cheap and nasty variety, trouble is bound to develop.
The fact that a putty has become loose does not necessarily imply that it is of poor quality. The woodwork on which it was used may not have been properly sealed by paint before the putty was applied, with the result that it has absorbed the oil from the putty, which has consequently shrunk.
Alternatively, the work has not been adequately painted after puttying, so that moisture has crept in.