Media Blasting & Metal Preparation. Matt Joseph

..."/>

       Modern Gunk Carburetor Parts Cleaner is a good and relatively inexpensive immersion cleaner that is milder than the Hydro Seal II–type layered carburetor cleaners. It lacks the ability to seal porosities in die-cast metal parts, one of the features of some of the older carburetor cleaners.

      To use these layered cleaners, parts were placed in metal mesh baskets and lowered into the bottoms of the drums (usually 5-gallon capacity) in which these cleaners were shipped. In a matter of hours, soils such as carbon, varnish, paint, and more were dissolved and removed. The time required depended on which product you used and how dirty the parts were. It also depended on the temperature of the solution.

      After an hour to a day, the parts were pulled up through the solutions. Each layer of the solution had a different function. Cleaning layers dissolved and removed soil. Coating layers sealed porosities in the metal surfaces. The top layer was always water. Water was always the final rinse cleaner; it kept the volatiles in the chemicals below from evaporating.

      These were marvelously effective cleaners, but they contained several dangerous components that caused environmental degradation. Most of them went out of manufacture decades ago. One exception is Gunk Hydro Seal II, which, while it is a terrific solvent, lacks some of the intricate and sophisticated chemistry of the earlier solvents of this type. It is also quite expensive.

      I go into detail on the old layered fuel system parts cleaners because you may find references to using them in old rebuild manuals. For all practical purposes, these products no longer exist in anything like their original formulations, and it is best to find other, more modern approaches to cleaning the kinds of parts for which they were designed and/or specified. Actually, the external diecast fuel pumps and complex carburetors for which these cleaners were developed have also been absent from automotive production since the demise, decades ago, of non-submersible fuel pumps and throttle body injection systems.

Electrolytic and Chemical Processes

      Electrolytic cleaning is generally considered an industrial process. It has applications in fields such as electroplating where current is run between anodes and cathodes attached to parts suspended in chemical solutions. Names for this process in plating vary. “Pickling” and “reverse plating” are among the most common monikers for it.

      In electrolytic cleaning processes, parts are attached to the anode (-, in the case of reverse plating) in the system. Current flows to the cathode (+, in the case of reverse plating), which is in circuit with a conductive acid bath in which the parts are immersed. The result is to remove molecules of conductive contaminants, such as old plating, from the parts and deposit them on the metal cathode in the plating solution. For the most part, and with very few exceptions, “Don’t try this at home.”