(See also Enamels, Glazes, Paints, Preservatives, Varnishes.)

Waterproofing Brick Arches

Waterproofing of brick arches is done in the following manner: The masonry is first smoothed over with cement mortar. This is then covered with a special compound on which a layer of Hydrex felt is laid so as to lap at least 12 inches on the transverse seams. Five layers of compound and 5 of felt are used, and special attention is paid to securing tightness around the drain pipes and at the spandrel walls. In fact the belt is carried up the back of the latter and turned into the joint under the coping about 2 inches, where it is held with cement mortar. The waterproofing on the arches is protected with 1 inch of cement mortar and that on the walls with a single course of brickwork.

Waterproofing Corks

For the purpose of making corks as impervious as possible, while at the same time keeping them elastic, saturate them with caoutchouc solution. Dissolve caoutchouc in benzine in the ratio of 1 part of caoutchouc to 19 parts of benzine. Into this liquid lay the corks to be impregnated and subject them to a pressure of 150 to 180 pounds by means of a force pump, so that the liquid can thoroughly enter. The corks thus treated must next be exposed to a strong draught of air until all trace of benzine has entirely evaporated and no more smell is noticeable.

Waterproof Coatings

I

Rosin oil, 50 parts; rosin, 30 parts; white soap, 9 parts. Apply hot on the surfaces to be protected.

II

It has been observed that when gluten dried at an ordinary temperature, hence capable of absorbing water, is mixed with glycerine and heated, it becomes water-repelling and suitable for a waterproof paint. One part of gluten is mixed with 1.5 parts of glycerine, whereby a slimy mass is obtained which is applied on fabrics subsequently subjected to a heat of 248° F. The heating should not last until all glycerine has evaporated, otherwise the coating becomes brittle and peels off.