quick and brilliant finish, but the surface of the metal will corrode all the faster afterward and will soon become eaten and pitted until ruined. It is far safer and better to make your own polish and it will cost far less in the end. For rough work, where old corroded brass is to be cleaned, cylinder oil and the finest pumice stone may be used, but for ordinary work or on brass that is in good condition a mixture of rotten-stone and oil, crocus powder and oil, jeweler's rouge and oil, or oil and whiting should be used. If a more liquid polish is desired, a little kerosene may be added until the desired consistency is obtained, while a paste may be made by adding hot paraffine or tallow until the mass partly solidifies when cold. After polishing with any of the above a highly finished result will be obtained by wiping with kerosene and rubbing with precipitated chalk. Steel or iron that has become rusty but should have a bright finish may be polished by scouring with emery and oil or emery paper, and afterwards finishing with pumice and oil or rotten-stone and oil. It is better, however, to finish all iron and steel with paint or enamel. Any good engine enamel will answer for most places, but on the exhaust and cylinders a special enamel should be used. For cylinders the highest-grade engine enamel should be used or an enamel made by mixing the color desired with the best quality Japan varnish. S S Fig 152. Shims for Inserting Piston On exhaust pipes and mufflers few paints or enamels will stand, but graphite mixed with linseed-oil will last longer than any other compound. Before applying paint or enamel to any part of a motor the portion to be painted must be thoroughly cleaned from grease or oil and smoothed bright and clean with emery paper. Old paint or enamel should be smoothed off with emery paper, and if any looseness or cracks appear the old paint should be burned and chipped off to the iron. Parts that rub or bear together, or bearings, should not be painted; many troubles have been caused by painting springs, valve stems, carburetors, igniters, and wires. Where belts are used there will often be trouble with their slipping, especially where the drive is short. Around water, or in boats, leather belts should be avoided. For pump drives, etc., wire-coil belting or sprockets and chains are better than anything else, but even wire belts will at times slip on the pulley wheels. When this occurs wrap two or three turns of adhesive tape around the wheel in the groove, being careful to have the tape wound in the direction of drive so it will not work up. Cotton-web belts are better than leather in most cases, and rubber is also excellent; while for very long drives nothing excels good manila rope spliced together. When belts slip they should be treated with some compound or belt-dressing. Many excellent dressings are on the market, but I have found that resin. dissolved in gasolene and sprinkled on the belt is the best thing in an emergency. This should not be used freely on leather belts, however, for the gasolene soon ruins the leather. Perhaps the best material for making a belt stick and pull is common tar soap. By holding a cake of this against a moving belt it can be evenly distributed and the belt will at once cease slipping. In winter time some provision should be made for preventing water from freezing in the tanks, pipes, radiator, and jacket of stationary and vehicle motors. In marine engines the water may be drained off to prevent this trouble, but in automobiles and stationary engines it is better to add some substance to the water. Glycerine, calcium chloride, salt, and various other substances are used, but these are all more or less injurious to metals or rubber pipe. The best material is denatured alcohol. This is cheap, it will not injure any portion of the motor, and it will prevent freezing even at the lowest temperatures. It is better to keep too much rather than too little alcohol in the water, and as the alcohol evaporates rapidly when heated it should be kept up to its proper percentage by adding more alcohol from time to time. When all danger of freezing is past, the water should be thoroughly drained off and new water put in its place. I have usually found that a IO-per-cent solution of alcohol (1 gallon to 10 gallons of water) is safe, and it is very seldom that the temperature goes low enough to endanger a mixture of this proportion. If alcohol cannot be procured, a solution of equal parts of glycerine and water, or a solution of 5 pounds of calcium chloride to a gallon of water will prove perfectly safe. A solution that is said to be non-corrosive and will withstand a temperature of 20 degrees below zero is made by combining 75 parts of carbonate of potash with 50 parts of glycerine and 100 parts (by weight) of water. Cause Air in Timer advanced too far. Motor Batteries old or wet. Two bat- Remedy Mend leaks, or if air-lock, prime Retard spark. Look after Test batteries. Replace with If fastened with staples re- |