CHAPTER VIII. 



Cements, Mortars, Paints and Glues. 



Cement and Mortar. — 



Cements for Iron. — 1. Sal ammoniac. 2 ozs. : sulphur, 

 1 oz. : clean iron-borings or filings reduced to powder, 12 lbs. ; 

 water enough to form a thin paste. 



2. Sal ammoniac. 2 ozs. ; iron-filings, 8 lbs. : sufficient 

 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 lbs.; pipe-clay, 2 lbs.; powdered pot- 

 sherds. 11 lbs. : 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 pulverized, 

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

 of manganese. of sea salt and % of borax ; mix well, and 

 reduce to a thick paste with water. Use immediately. Ex- 

 pose 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. — 1. Chalk. 60 parts : lime and salt, of 

 each. 20 parts; sharp sand. 10 parts; blue or red clay and 

 clean iron-filings, of each. 5 parts. Grind together and cal- 

 cine or heat. 



2. Powdered clay. 6 lbs. ; iron-filings. 1 lb. Make into a 

 paste with linseed oil. 



(7i) 



