cements, porcelain

Значение термина cements, porcelain в knolik

1. Add plaster-of-Paris to a strong solution of alum till the mixture is of the consistency of cream. It sets readily, and is said to unite glass, metal, porcelain, etc., quite firmly. It is probably suited for cases in which large rather than small surfaces are to be united.
2. Milk is coagulated by means of acetic acid, and the casein thus formed is well washed in water, and then dissolved in a cold saturated solution of borax; a clear solution is thus obtained which is superior to gum arabic in adhesive power, and is colourless. For porcelain, this liquid is mixed with finely powdered quicklime, and the resulting cement is quickly brushed over the fractured surfaces, which are then bound together; the ware is then dried at a gentle heat. ('Dingler's Polytech. Jl.')
3. To resist heat. It is made of Stourbridge clay mixed with a little tow or asbestos to increase its coherence. It should be well beaten before application; the glass or china should be first rubbed over with a little of the cement mixed with water, taking care to press the two edges of the glass or china together. This cement will bear a very strong heat.
4. Take isinglass ½ oz., proof spirit sufficient to dissolve it; to every 2 dr. add finely powdered mastic and finely powdered gum ammoniacum - of each 10 gr. Stir till dissolved. In using, heat the edges to be joined, and let the cement get thoroughly dry before using the article. The gums should be added to solution of isinglass when hot.
5. Calcine oyster-shells; pound and sift them through a sieve, and grind them on a flat smooth stone with a muller, till reduced to the finest powder; then take white of egg, and form the whole into a paste. Join the pieces of glass or china and press together 6 or 7 minutes. This cement will stand both heat and water, and will never yield, if properly done.
6. Plaster-of-Paris and gum. For very small articles this cement answers very well, but must not be too thick when well mixed.

Рядом со словом cements, porcelain в knolik