186 TECHNICAL BULLETIN 13 



The action of the various powders upon glass is ratlier severe over long 

 periods of time. With bottles, the length of life is so short that the corrosive 

 effect does not need to be considered. However, with tiie new glass-lined 

 vats the problem might become important. In the order of their severity of 

 action lipon glass the several ingredients may be listed: hydroxide, phosphate, 

 carbonate and soap. 



Alkalies of any kind attack paint and so no strong cleaning solution should 

 be allowed to remain on painted surfaces for any length of time. 



Cleaners containing abrasives should be used sparingly, and only when 

 absolutely necessary. Any abrasive will wear away the surface over which 

 it is rubbed. If the surface is plated, the under metal will soon be exposed 

 and form an electrolytic cell with the metal used in plating. This causes 

 increased corrosive action. Also the grit present is very hard to rinse off. 



On the average, five to six pounds of powder to a hundred gallons of water 

 may be regarded as the proper strength solution for ordinary hand washing. 

 This of course will vary with the particular powder used and the hardness of 

 the water. Smaller amounts of any powder are not to be recommended even 

 though the sales agent may speak very highly of his product and what it will 

 do. The majority of the powders on the market may be classified under three 

 heads having nearly the same composition, and a high price does not neces- 

 sarily infer any greater efficiency. Prices quoted different consumers vary 

 greatly even for the same product from the same manufacturer and, of 

 course, vary with the size of the order. The current prices for the basic in- 

 gredients are as follows: 



Sodium cart)onate $0.90-$1.30 cwt. depending upon purity. 



The unrefined material is satisfactory. There are several grades 

 depending upon the water content: as soda ash, NajCOs; crystal 

 carbonate, NajCOs.HjO; and soda crystals or washing soda, 

 NaoCOs-lOHjO. Soda crystals contain 63 per cent water. One ton 

 of crystal carbonate contains as much alkali as 48 cwts. of soda 

 crystals and occupies only half as much space. The soda ash is 

 highly concentrated and is liable to cake. It is higher priced and 

 has no advantages. 



Sodium bicarbonate $2.00 cwt. 



Sodium hydroxide 3.00 cwt. 



Tri-sodium phosphate 4.00 cwt. 



The 60 per cent carbonate — 40 per cent phosphate (12 HjO) reconuuended 

 in the following pages would cost $2.20 per cwt., or a little over 2 cents per 

 pound for raw products. The cost of mixing would be negligible. 



Soap prices are omitted because they would vary greatly depending upon 

 the purity of the product, and because soap is not considered advisable for 

 use. 



Thus it is evident that users of large amounts of wasiiing powder would 

 find it profitable to buy their own stock and mix their own powders. Smaller 

 dealers might not be sufficiently reimbursed for the trouble. Great care is 

 necessary to protect the eyes from alkali dusts. Also the dust is irritating to 

 the throat and nose. Therefore the mixing should be done in an enclosed 

 room, and the man doing the mixing should be protected by a sponge through 

 whicii to ])reathe, and his eyes protected by goggles. 



The temperature of the washing solution should not much exceed 140° F. 

 or 60° C. because, if allowed to do so, the precii)itated casein and gununy 



