536
(c) the cement is then made up into briquetters from 23% down to 19% of water by weight being used. The amount of water depending upon the make of the cement and other conditions such as age, rate of setting - 9%. The mixture is thoroughly worked up, and filled into the moulds, which are struck level, marked & dated. The time taken for the cement "to set" is noted.
The number of briquettes gauged for each delivery may be from 12 to 14 - taken as ...
When set, the briquettes are placed in water.
(d) at the expiration of 7 days, the briquettes are tested - the bulk of them in your Standard machine with automatic feed at the rate of 105 lbs per 15 seconds - others in a Michel's hand-fed machine or on Porter's 1"x1" Spring feed Machine. The results are averaged, and if over 787.5 lbs, the cement is accepted subject to the results of the pat tests.
(e) Pat's 5" x 5", 3/4" or thereabouts, are made with the same quantity of water as the briquettes. Two are put in water as soon as set. Two are kept exposed to the air. On the 4th day, one of each is heated in an oven of special construction, fitted with a thermometer. If they withstand a temperature of 160°F for 15 minutes without ...