By JOHN FRYE
Chemicals handle a wide range of electronic servicing problems-- from quick cooling for checking intermittents to making TV tuners, switches, and controls perform more reliably.
Here are the chemicals that are available, what they do, who makes them, how they are used, and precautions to observe.
EARLY physicists recognized a mysterious affinity between chemistry and electricity. Zinc and carbon plates immersed in a dilute sulphuric-acid solution created a battery and caused an electric current to flow through a wire connecting the plates. On the other hand, if two platinum conductors were placed in the same solution and connected to a battery, hydrogen gas formed at one electrode and oxygen at the other in a 2:1 ratio, the H2O of the solution being decomposed by electrolysis into its chemical elements. With the discovery of the electron theory the truly intimate relationship between the two fields was revealed.
Today electronics relies heavily and unabashedly on chemistry at all levels from research through manufacturing to service. This article will, of necessity, restrict itself to a small segment of this immense field: aerosol chemicals designed to aid the electronics technician. Even with this restricted focus, the treatment cannot hope to be exhaustive; but we will try to give an idea of representative chemicals that are available, who makes them, why they were developed, how they are used, and what precautions should be observed with them.
Aerosol-type service aids can be arbitrarily divided into cleaners, lubricants, insulating coatings, and DP miscellaneous. Each of these four categories can again be arbitrarily divided and subdivided. We say "arbitrarily" because many spray products, as you will see, are designed to do two, three, or even four jobs, while others are highly specialized.
Deadly carbon tetrachloride was probably the first service chemical used lavishly in all innocence by technicians to clean contacts. It was an excellent degreaser, but it left naked contact riding on naked contact, and they soon failed. What was needed was a general-purpose non-toxic chemical that would (1) dissolve and wash away grease, oxidation, and corrosion from the contacts; (2) evaporate completely leaving no residue; (3) coat the contacts with a long-lasting protective lubricant; and (4) be easy to apply to difficult-to-reach contacts. Many manufacturers have come up with just such chemicals, and they have solved (4) by placing them in aerosol spray cans. Ideally, the contact cleaner has low surface tension for good wetting and penetration into tiny crevices and high density to give the spray weight for dislodging and washing away crud. Also, hopefully, it is non-explosive and nonflammable-but don't depend on this; read the instructions! Spray Contact Cleaners
General-purpose contact cleaners are used on all kinds of switch and relay contacts plus the contacts of all sorts of plug-in devices, including tubes. Application depends somewhat on the type of contact. With sliding contacts, such as rotary and slide switches, tuning-capacitor wipers, or plug-in devices, the spray is directed at the contacts, usually through the small plastic tube furnished with the spray.
After waiting a few seconds for the chemical to soften the oxidation, work the switch or tuning capacitor or insert and remove the plug-in device several times so the softened corrosion will be wiped away by the sliding action and the protective lubricant will be evenly distributed over the cleaned contacts.
Where wiping action is less pronounced, as in relay contacts, it may help to insert a piece of notepaper between the wetted contacts and hold them pressed against the paper while it is slid back and forth to wipe away the dirt; then spray the contacts again.
Here's a partial list of general-purpose contact cleaners together with their manufacturers: Chemtronics Contact Kleen, CRC CO Contact Cleaner, Crown Switch & Contact Cleaner, DCMC Electronic Switch Cleaner & Lubricant, Electronic Chemical Corp. (ECC) EC-44, Injectorall Electrical Contact Cleaner, GC Electronics Relay-Kleen, Action, and JIF; LPS Research Labs Instant Contact Cleaner, Miller-Stephenson Chemical Co. MS-230 Contact Re-Nu, Quiet-role Spray-Pack LubriCleaner and Silitron, RCA SC106 Deluxe Relay and Contact Cleaner, Sprayon Electrical Contact Cleaner. Trans Atlantic Electronics Electrolube 2A, 2A-X, and 2GA-X; and Workman Electronics Super Wissh Contact Cleaner.
Some chemical manufacturers felt another type of cleaner was needed for specific use on all types of variable-resistance controls. Aerosol sprays permit introducing the cleaner without dismantling the control. The spray can be introduced through crevices where the lugs emerge from the case or through small openings produced by stamping a rotation stop in the cover. Poor contact occurs more often between the rotor and the connecting lug than between the rotor shoe and the resistance element; so cleaner is needed especially at the sliding contact near the shaft.
Workman markets a clever tool, called Gozinta, to take care of this and to permit cleaning the control from the front without pulling the chassis. It consists of a tapered plastic tube threaded at the large end to screw onto the shaft collar of the control. The small end inserts into the aerosol-cleaner outlet, and pressure forces the cleaner around the shaft into the control. In all cases, after the cleaner is sprayed into the control the shaft should be turned back and forth through full rotation several times. If this does not clear up erratic operation, the resistance element is probably worn and the control will have to be replaced.
Manufacturers and their products specifically recommended for cleaning controls are: Chemtronics Contact Kleen, ECC No Noise Volume Control & Contact Restorer, Injectorall Hi-Fi Control Cleaner, GC Spray-Pack and Silitron, RCA SC101 Heavy Duty Control Cleaner & Lubricant, and Workman Lubrite.
The most common use is to clean and lubricate TV tuner contacts.
--------- Chemicals are also used to clean the heads in tape machines.
When TV tuners came into use, they presented special problems with regard to contact cleaning. Not only were there lots of contacts carrying a wide variety of currents ranging all the way from d.c. to minute amounts of v.h.f. and u.h.f. radio frequencies, but in close proximity to these contacts were associated tuned circuits easily detuned by the presence of any foreign substance--including contact cleaner--in their fields.
Wide-ranging attempts to satisfy critical TV-tuner cleaning requirements result in a large number of products hard to catalogue, for each manufacturer has a somewhat different idea. One approach is to design a combination degreaser-cleaner in which the solvent cleans the contacts and evaporates, leaving a lubricant coating to protect the contacts. Other manufacturers feel no one product can do both cleaning and lubricating jobs properly; so they manufacture one evaporating lubricant-free cleaner to wash off accumulated grime and a second heavier lubricator-polisher to protect cleaned contacts. Other manufacturers make a tuner cleaner specifically for color-TV sets and still another for nuvistor I transistor tuners.
Since we are still talking about cleaners, we shall here discuss these TV-tuner cleaners: the degreaser-cleaners, color-TV tuner cleaners, and nuvistor I transistor-tuner cleaners. When we get around to talking about spray lubricants, we shall discuss the lubricator-polisher types of tuner cleaners. Remember, though, tuner cleaners do not always fit neatly into such categorizing. One-shot degreaser cleaners may also contain a lubricant; a color-TV tuner cleaner can safely be used on black-and-white sets; etc.
In applying any kind of aerosol tuner cleaner, it is well to keep these points in mind: (1) one-shot products with more lubricant usually protect better but detune more; (2) silicone lubricants last longer than petroleum lubricants; (3) avoid spraying any capacitive device, especially a neutralizing capacitor, or any coil; (4) don't drench the tuner with cleaner, confine the spray as nearly as possible to the contacts; (5) a better job can usually be done by removing the tuner and taking off the shield cover so contacts can be sprayed with greater force and precision; and (6) always follow the manufacturer's instructions.
Here are representative TV-tuner degreaser-cleaners and their manufacturers: Castle TV Tuner Service Muck Off, Channel Master Tuner Cleaner and Tuner Wash, ECC Super Bath Spray, Injectorall Spray-Clean and Economy Cleaner, Krylon No. 1333 Tuner Cleaner, Quietrole Mark II, Tech Spray Blue Stuff, and Workman Miracle Bath.
Higher picture-tube voltages in color sets cause more dirt to precipitate in their tuners. Critical tuning in color tuners can be seriously changed by the presence of lubricant in the wrong places. Such considerations have led to the marketing of sprays the manufacturers particularly recommend for cleaning color-TV tuners: Channel Master Chroma Foam, Chemtronics Color Lube, GC Color Magic Spray-Lube, Injectorall Super 100, RCA SC100 Deluxe Color Tuner Cleaner Lubricant, and Workman Color Tuner Toner.
Small neutralizing capacitors in nuvistor and transistorized tuners are particularly sensitive to the presence of some cleaners in their electrostatic fields. At least two manufacturers have produced tuner cleaners said to be safe with these sets: Chemtronics Tun-O-Lube 800 Transistor Tuner Cleaner and GC Nuvi-Tran Tuner Cleaner.
Spray chemicals are used to clean other things than contacts. For example, efficiency of record and playback tape heads of audio and video recorders are seriously impaired by the build-up of material lost from the tape that holds the tape away from the heads and partially short-circuits the magnetic fields of the gaps. The residue also collects on the capstan, pinch-roller, and tape guides and interferes with the proper transport of the tape past the heads. Several manufacturers market aerosol cleaners to wash away this material: Channel Master Tape Head Cleaner, Chemtronics THC-6, ECCTape-Reco Head Cleaner, Injectorall Clear Sound, GC Audio-Video Magnetic Tape Head Cleaner, Miller-Stephenson MS-200 Magnetic Tape Head Cleaner, RCA SC107 Deluxe Audio /Video Tape and Head Cleaner, and Workman 8 Heads Tape Head Cleaner.
Grease and other material collecting on dial-drive, tape recorder, and other belts encountered by the technician cause these belts to slip. Sprays to clean this material off the belts are made by: Crown Non-Slip Drive Belt Cleaner, Krylon No. 1330 Belt Dressing, and Sprayon No. 607 Belt Dressing.
Solder flux can be removed from where it is not wanted by Crown's Flux Remover, Miller-Stephenson's MS-190 / MS-190HD Flux Removers, and Sprayon's Freon TMC Cleaner.
Rust and corrosion are always a problem in TV antennas and towers as well as automotive installations, so several manufacturers have come up with products that we group together as rust removers, rust inhibitors, and penetrating oil. These sprays are excellent to loosen rusted nuts or frozen yokes or other seized unions of two pieces that should move freely and to keep rust and corrosion from returning.
Examples include: Chemtronics Chem-Oil, CRC 2-26, Crown Penetrating Cleaning Oil, Rust Inhibitor, and Formula 101; Krylon Let-Go No. 1332, LPS #1, #2, and #3; Miller-Stephenson MS-150 En-Rust, C. H. Mitchell Co. 12/ 34 Miracle Formula, and Sprayon Penetrol, PDRP, Anti-Rust Spray, and Penetrating Oil No. 203.
Occasionally the technician needs a really heavy-duty cleaner to remove sludge from an antenna rotating motor, an over-oiled phono motor, etc. He will find same in CRC's Lectra-Clean and Krylon's Electric Motor Cleaner.
An allied problem is the need to remove moisture from motor windings or to pull the water out of a transistor radio that has been dropped in the lake. The need is met by LPS's #2 or #3 and by Sprayon's Quik-Dri De-moisturant No. 2004.
Finally, after the technician has done all this cleaning, he is likely to need a little cleaning himself, and he has not been forgotten. An aerosol can of CRC's Electrical Antiseptic Hand Cleaner or Crown's Foaming Hand Cleaner in his tool-box will allow him to lay immaculate hands on that blonde TV cabinet.
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Q & A on Sprays
Editor's Note: While we were gathering material for this article, we found the following interesting and informative questions and answers on aerosol spray chemicals in a catalogue put out by Sprayon Products, Inc. We'd like to share them with our readers.
What Makes It Spray? About half the contents is liquid gas in solution with the product (A). At 70 °F, there is a pressure of about 35-38 pounds per square inch. So when the push-button valve is depressed, the head pressure from the vaporized gas in the can forces out the product, liquid-gas solution. The gas vaporizes instantly in the free air-in a sense, explosively atomizing the particles of the products which are deposited as a smooth film.
How Long Can It Be Stored?
Aerosol products were relatively new in 1948, but samples held since then have worked successfully. The can is hermetically sealed, and not much can happen to it. Perhaps over a period of many years, the valve and can gasketing material might break down, but the gas has no effect on the product.
What About Clogging?
A properly formulated product-gas solution should yield a package practically free of what used to be the No. 1 complaint-clogging. Paint products will dry and harden, and unless certain simple precautions are taken, heavy pigmented enamels-not lacquers-may tend to block the small pinhole openings in the valve. If the can is merely inverted after use, the valve released, and a jet of clear gas passed through the valve, the valve will be self-cleaned and will always operate free of trouble (B). If this precaution is neglected, pull off plastic valve head, clean it and valve core.
Can You Use All of It?
There is more than enough gas to spray the entire contents. Sometimes, however, one unacquainted with the "insides" will try to use the can in the wrong position (C). Obviously only clear gas will come out. Merely turn the plastic valve head a half turn, and the plastic tube will then dip into the solution and the last drop will be as uniform as the first. The gas has the unique property of liquefying at low pressure, and only enough gas will vaporize inside the can to maintain a constant head pressure.
How Should It Be Stored?
Remember that gas pressure increases at a rapid rate as the temperature increases. All aerosol products are tested at 130 °F temperatures (ICC Regulations), but they should not be exposed to temperatures over 120 °F. Also, use caution in disposing of empty cans. They should never be incinerated or thrown in a rubbish fire. There is still residual gas that might burst the can. Do not puncture the can or you will have an "unwieldly" stream of paint, or whatever the product might be, on your hands.
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So much for the "cleaners." As we warned you, many of them do lots more than clean, but their essential role is that of a burlesque queen-to take things off. Now we turn to the spray products whose basic purpose is to lubricate.
Spray Lubricants
First, let's return to the unfinished business of the TV tuners that were cleaned and not lubricated or to those in which we feel we need to place a polishing lubricant to keep the contacts bright. In applying these, great care should be used to direct the spray only at the contacts and not to over-spray. Examples include: Castle Intimate Contact, Chemtronics Tun-O-Brite and Tun-O-Foam, ECC Super-Lube, Injectorall Blue Lube, GC Magic Vista, and Workman Foamy White Lubrite. Note some of these clean as well as polish and lubricate the contacts. They are grouped here because their makers emphasize lubrication.
As long as mechanical parts are designed to rotate and slide together, the technician will need a light lubricating oil to facilitate this action. He needs such an oil especially for use with record players, tape recorders, remote control motors, switch-latching mechanisms, and detent mechanisms. Several manufacturers package such a lubricant in spray cans for putting the oil into hard-to-reach areas: Chemtronics Chem-Oil, GC Pressurized Lubricating Oil, RCA SC105 Deluxe Multi Purpose Lubricant, and Workman Spray Oil.
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A listing of manufacturers and the spray-chemical products that they make.
MANUFACTURERS
Castle Television Tuner Service, Inc. C,M 5710 N. Western Ave., Chicago, Ill. 60645 Channel Master Div., Avnet, Inc. C,D,F,T Ellenville, N.Y. 12428 Chemtronics A, B,D,E,F,I, M, N,Q,R,T 1260 Ralph Ave., Brooklyn, N.Y. 11236 CRC Chemicals A J,L,Q Div. C.J. Webb, Inc. Dresher, Pa. 19025 Crown Industrial Prods. Co. A,G,H,I,L,O,Q,S,T,U 100 Stateline Rd., Hebron, Ill. 60034 DCMC International Inc A,Q,S,U 239 Great Neck Rd., Great Neck, N.Y. 11021 Electronic Chemical Corp. (ECC) A,B,C,F,M,T 813 Communipaw Ave., Jersey City, N.J. 07304 Emerson & Cuming Inc Q,V Dielectric Materials Div., Canton, Mass. 02021 Epoxy Products Co., Div. Allied Prods. Corp. V 166 Chapel St., New Haven, Conn. 06513 GC Electronics, Div. Hydrometals Inc A,B,D,E,F,M,N,Q,R,T 400 S. Wyman St., Rockford, Ill. 61101 General Electric Co., Silicone Prods. Dept 0 Mechanicsville Rd., Waterford, N.Y. 11218 Holub Industries Inc P Sycamore, Ill. 60178 Injectorall Electronics Corp. A,B,C,D,F,M,Q,R,S,T 4 North Rd., Great Neck, N.Y. 11024 Krylon Dept., Borden Chemical Inc C,G,I,J,O,Q,U 350 Madison Ave., New York, N.Y. 10017 LPS Research Labs, Inc. A I K 2050 Cotner Ave., Los Angeles, Calif. 90025 Merix Chemical Co S 2234 E. 75th St., Chicago, III. 60649 Miller-Stephenson Chemical Co. Inc. A,F,H,I,S,T Route 7, Danbury, Conn. 06813 C.H. Mitchell Co., Electronic Tools Div 18531 Ventura Blvd., Tarzana, Calif. 91356 Quietrole Co A C Box 2607, Station A, 395 St. John St., Spartanburg, S.C. RCA Parts and Accessories A,B,D,F,N,Q,R,S,T 2000 Clements Bridge Rd., Deptford, N.J. 08096 Sprayon Prods. Inc. A,G,H,I,K,Q,S,T 26300 Fargo Ave., Bedford Heights, Ohio 44146 Tech Spray C Amarillo, Texas Tempi) Div., Big 3 Industries Inc. W Hamilton Blvd., So. Plainfield, N.J. 07080 Trans Atlantic Electronics Inc. A 55 Bloomingdale Rd., Hicksville, N.Y. 11801 3M Co., Adhesives, Coatings & Sealers O,U 3M Center, St. Paul, Minn. 55101 Workman Electronic Prods. Inc A B,C,D,F,M,N Box 3828, Sarasota, Fla. 33578
KEY TO PRODUCTS CLEANERS
A. General-purpose contact cleaner
B. Control cleaner
C. TV tuner degreaser /cleaner
D. Color-TV cleaner
E. Nuvistor /transistor tuner cleaner
F. Tape-head cleaner
G. Non-slip belt cleaner
H. Flux remover
I. Rust remover, inhibitor, penetrating oil
J. Heavy-duty cleaner
K. Moisture remover
L. Hand cleaner
LUBRICANTS
M. TV tuner polisher-lubricant
N. Light lubricating oil
O. Silicone coating
P. Wire-pulling lubricant
INSULATORS
Q. Insulating spray, protective coating
R. High-voltage spray
S. Anti-static spray
MISCELLANEOUS
T. Cooling spray
U. Adhesive spray
V. Conductive coating
W. Temperature-indicating spray
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------ Many companies have a complete line of chemicals for servicing.
When a lubricant is needed that will not run, gum, or form residues; that forms a protective seal against water or corrosion; that preserves and lubricates rubber, wood, and even aluminum; and that will not contaminate surfaces to prevent later painting, a silicone lubricant is indicated. This spray lubricant keeps antenna rotors and turntables turning smoothly, protects connections from moisture and corrosion, prevents doors and locks of the service truck from freezing, and even keeps the zipper on your service jacket working smoothly! Such lubricants are: Crown Silicone Lubricant and Slix-it, General Electric Silicone Lubricant, Krylon All-Purpose Silicone Spray and Heavy Duty Silicone Lubricant, and 3M Spray Silicone. Finally, if you pull a lot of coax through conduit while installing TV-distribution systems, Holub Industries' Hi-Green Wire Pulling Lubricant can make your job easier.
Spray Insulators
But now let's turn to sprays intended primarily to insulate and protect.
These are sprayed on everything from outdoor antenna connections to printed circuits after making a repair. Most technicians are familiar with at least one of the following: Chemtronics Kleer Spray, CRC Red Urethane Seal Coat, Crown Kleer Kote, DCMC Vinyl Protective Coating Spray, Emerson & Cuming Eccospray AC-6, Injectorall Clear Spray Plastic Coating, GC K27 Print-Kote Silicone Resin Lacquer, Krylon Crystal Clear Acrylic Spray Coatings, RCA SC104 Deluxe Acrylic Spray, and Sprayon No. 2000 Clear Acrylic.
High-voltage sprays, of course, are intended to prevent arcing and corona in components carrying the high voltage to the picture tube. A listing includes: Chemtronics No Arc High Voltage Insulator, Injectorall Hi-Volt Red Insulator Spray, GC Red-X TV Corona Dope, and RCA SC103 Deluxe Red Corona Spray.
Every technician knows how a static charge on a plastic or glass meter face, the safety barrier of a picture tube, or even records can be annoying. These products are intended to "insulate" such surfaces from static charges: Crown Anti-Static Spray, Injectorall Lens Kleen, DCMC 865 Anti-Static Spray, Merix No. 79 and 790L Anti Static, Miller-Stephenson MS-166 EnStat, RCA SC108 Deluxe Anti-Static Record Spray, and Sprayon No. 610 Anti-Static Spray.
Miscellaneous Sprays
At last we arrive at our final group: miscellaneous. The cooling spray is the most popular of this group. It is essentially a refrigerant gas that abruptly lowers the temperature of any object struck by the spray. The chief use is to locate thermal intermittents in electronic circuits. After a chassis is hot, the spray can be directed at each component or printed-circuit conductor in a suspected circuit, and the one resulting in a dramatic change in sound or picture when cooled is the culprit. A shot of the cooler will also protect transistors, germanium diodes, and other heat-sensitive devices from damage while their leads are being soldered.
One enthusiastic manufacturer even insists his cooling spray is good for snake bites! He says the cooling action of the spray directed on the bite slows down the spread of the poison. Most technicians we know rely on another liquid for snake bite.
At any rate, here are the manufacturers and their colorfully named products: Channel Master 50° Below, Chem-tronics Frost Aid and Super Frost Aid, Crown Freeze-It, ECC Frigid-Air, Injectorall Chill-It, GC Super Freeze Mist and Extra Dry Super Freeze Mist, Miller-Stephenson Quik-Freeze, RCA SC102 Deluxe Circuit Chiller, and Sprayon Circuit Cooler.
Sometimes a technician wants to paste a label, instructions, or a diagram on a component or inside a cabinet.
One of the following spray adhesives makes this easy. Crown General Purpose or Heavy Duty Pressure Sensitive Adhesives, DCMC Spray & Stick Adhesive, Krylon Pressure Sensitive Spray Adhesive, and 3M Scotch-Grip Spray Adhesive 77-N. Conductive coatings, as well as insulating coatings, come in aerosol cans.
They consist of fine metallic particles, usually silver, and a lacquer-type binder. When sprayed on almost any surface a continuous metallic coating is produced that is used for transistor heat sinks, capacitor plates of printed circuits, making connections to non solderable units, repairing PC conductors, and creating r.f. shielding. Emerson & Cuming manufactures Eccocoat CC-2 Highly Conductive Surface Coating while Epoxy Products Co. makes E-Kote 40 Silver Conductive Paint.
The last item we have space to mention is a temperature-indicating paint called Tempilaq manufactured by Tempil. This consists of materials of calibrated melting points suspended in an inert, volatile, non-flammable vehicle. Over 100 different temperature ratings from 100 °F to 2500 °F are available. A mark of Tempilaq is sprayed on a transformer, tube envelope, or transistor case whose temperature you wish to check. If the mark liquifies and remains glossy-transparent on cooling, you know the temperature rating of that particular Tempilaq has been exceeded. By employing several marks made with different temperature ratings, you can tell how hot the unit became.
Common-sense measures should be observed in using all chemical sprays.
Always spray away from yourself and never toward the eyes. Don't breathe the fumes even if they are claimed to be non-toxic. Do not spray freezing chemicals on the skin or you may end up with frostbite. Keep aerosol cans away from excessive heat. Always double-check to be sure you have the right can before you push that button. A friend who sprayed the multi-bank band-change switch of an expensive communications receiver with what he thought was contact cleaner but was really acrylic spray wished he had!