Abstract: A coolant recycling apparatus has a boiler and condenser for distilling a glycol and water from a used coolant. The glycol and water are recombined in a mixing tank to form a mixture having a desired ratio of water to glycol, and an inhibitor is added to the mixture to obtain a fresh coolant mixture ready for use in an engine cooling system. Contaminants in the used coolant are concentrated to form a sludge.

Abstract: A method of joining metal surfaces is provided which comprises contacting the metal surfaces with a zinc-based composition and joining the metal surfaces, the zinc-based composition comprising, by weight:from about 0.1 to about 4 percent copper;from about 0.1 to about 1 percent nickel;from about 0.01 to less than 0.5 percent aluminum;0 to about 0.5 percent chromium;0 to about 0.5 percent titanium; and the remainder being zinc is also provided. The composition is useful for coating metal surfaces, particularly metals formed of or containing copper.The above composition and method may be used with or without a flux. Particularly beneficial results are obtained when a flux having a composition comprising, by weight:from about 5 to about 70 percent ZnCl.sub.2 ;from about 1 to about 28 percent NH.sub.4 Cl;from about 0.1 to about 10 percent SnCl.sub.2 ;from about 0 to about 10 percent HCl;from about 0 to about 10 percent Li.sub.2 B.sub.4 O.sub.7 ;from about 0 to about 5 percent MgBr.sub.

Abstract: A zinc-based composition comprising, by weight:from about 0.1 to 4 percent copper;from about 0.1 to about 1 percent nickel;from about 0.01 to less than 0.5 percent aluminum;0 to about 0.5 percent chromium;0 to about 0.5 percent titanium; and the remainder being zinc is provided. The composition is useful for coating or joining metal surfaces, particularly metals formed of or containing copper.The above composition may be used with or without a flux. Particularly beneficial results are obtained when a flux having a composition comprising, by weight:from about 5 to about 70 percent ZnCl.sub.2 ;from about 1 to about 28 percent NH.sub.4 Cl;from about 0.1 to about 10 percent SnCl.sub.2 ;from about 0 to about 10 percent HCl;from about 0 to about 10 percent Li.sub.2 B.sub.4 O.sub.7 ;from about 0 to about 5 percent MgBr.sub.2 ;from about 0 to about 5 percent ZnBr.sub.2 ; and about 0 to about 94 percent water is used.

Abstract: A zinc-based composition comprising from 0.01 to 5 percent lead and 0.01 to 20 percent tin, preferably minor amounts of chromium and/or titanium and/or nickel and with the balance being zinc is provided. A minor amount of copper may also be present. The composition is particularly useful for joining copper and copper alloys because it will wet and readily flow on the copper or copper alloy surfaces. It can be used with or without a flux. It has reduced dissolving action on the copper and copper alloys due to its reduced reactivity with them. It also has improved conductivity vis-a-vis conventional lead-tin and lead-tin-silver solders.