A cement for fastening glass work to brass tubes is made of rosin, 5 ounces; beeswax, 1 ounce; and red ochre or Venetian red, in powder, 1 ounce.
Birmingham, Eng. W. R. Bowers.
It is often necessary, in electrical factories and repair shops, to cement small brass parts to glass. A good cement for this purpose is made from the following: 1 part caustic soda, 3 parts resin, 3 parts plaster of paris, 5 parts water. Boil all the constituents together until thoroughly mixed, and then allow to cool before using. The cement hardens in half an hour. If it is desired that it should not harden so quickly, substitute zinc white, white lead, or slaked lime, for the plaster.
Urbana, Ill. T. E. O'Donnell.
To make a cement for attaching metal to glass mix 2 ounces thick glue, 1 ounce linseed oil, ½ ounce turpentine. Boil together for a short time when it will be fit for use. Apply hot with a brush and clamp the parts together for about two days to allow the cement to dry.
R. M. K.
Melt together in a water bath 15 parts of copal varnish, 5 parts of drying oil, and 3 parts of turpentine. When the ingredients are well mixed add 10 parts slaked lime. An elastic cement for fastening brass to glass may be made by mixing 5 ounces of resin, 1 ounce beeswax, and 1 ounce of red ochre or Venetian red in powdered form. Melt the rosin and beeswax together by gentle heat, and gradually stir in the Venetian red. W. R. Bowers.
A good cement for making repairs on switchboards, when iron or other metal has to be fastened to marble, or where binding posts have been pulled out, may be made to consist of 30 parts plaster of paris, 10 parts iron filings, and ½ part of sal-ammoniac. These are mixed with acetic acid (vinegar) to form a thin paste. This cement must always be used immediately after being mixed, as it solidifies if allowed to stand for any length of time. It will be found to be an excellent means for filling up old binding-post holes, when instruments have been moved. T. E. O'Donnell. Urbana, Ill.