This job is not difficult, but requires great care. First of all, the exact measurement of the glass required should be obtained and given to a glazier, with instructions to cut the appropriate quality and thickness of glass to this measure. Quarter-inch glass should not be put into a window where other panes are three-eighths of an inch, and the exact thickness necessary should also be given to the glazier.
Having obtained the glass, the required amount of putty must be prepared by mixing whitening and linseed oil—adding the oil to the whitening until the right consistency is reached. Be careful to break up any lumps in the whitening before adding the oil. This may also be prepared by mixing white lead and dry well-powdered whitening.
With an old knife, all broken glass and old putty should be removed from the window-frame, a layer of putty run finely round the beading of the frame, and the glass fitted into this. Then, take the putty in small pieces and press into place, levelling up from about an eighth of an inch from the edge of the glass to the rim of the frame. This, when dry, will make a solid mass which will hold the glass in place, and yet possess sufficient ‘give’ to allow for expansion and contraction, and vibration from traffic. Do not clean the window until the cement is quite set. The putty when dry may be painted the same shade as the rest of the window frame. Never have the glass too tight ; it should fit easily, but not too easily into the frame. If it is too tight, no allowance is made for expansion or vibration—which will result in breaking sooner or later. Never use putty too stiff to work.