CHAPTER VIII. 



CEMENTS, MORTARS, PAINTS, AND GLUES. 



L. Cement and mortar. 

 Cements for Iron. — 



1. Sal ammoniac, 2 ounces ; sulphur, 1 ounce ; clean iron- 

 borings or filings reduced to powder, 12 pounds ; water 

 enough to form a thin paste. 



2. Sal ammoniac, 2 ounces ; iron -filings, 8 pounds ; suf- 

 ficient water. 



3. 1 or 2 parts of sal ammoniac to 100 of iron-filings. 

 When the work is required to set quickly, increase the sal 

 ammoniac slightly and add a small amount of sulphur. 



4. Iron-filings, 4 pounds ; pipe-clay, 2 pounds ; powdered 

 potsherds, 11 pounds; make into a paste with moderately 

 strong brine. 



5. Equal parts of red and white lead, mixed into a paste 

 with boiled linseed oil. Used for making metallic joints of 

 all kinds. 



6. To 4 or 5 parts of clay, thoroughly dried and pulver- 

 ized, add 2 parts of iron-filings, free from oxide, 1 part of 

 peroxide of manganese, | of sea salt, and i of borax ; mix 

 well, and reduce to a thick paste with water. Use immedi- 

 ately. Expose to warmth, gradually increasing almost to 

 white heat. 



7. Sifted coal ashes, 2 parts, and common salt, 1 part. 

 Add water enough to make a paste and apply at once. 

 This is also good for stoves and boilers, as it stands 

 heat. 



Boiler Cements. — 



8. Chalk, 60 parts; lime and salt, of each, 20 parts;. 



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