Painted Aluminum Research Articles

High Voltage Transmission Microscopy of Surveyor III Camera Shrouds

Successful retrieval of the television camera and other components from the Surveyor III spacecraft by the Apollo 12 astronauts has provided a unique opportunity to study the effects of a known and relatively extensive exposure to the lunar environment. Microstructural effects including those produced by micro-meteorite impact, radiation damage (by both the solar wind and cosmic rays) and solar heating might be expected in the materials used to fabricate the spacecraft. Samples received were in the form of 1 cm2 of painted unpainted aluminum alloy sheet from the top of the camera visor (JPL Code 933) and the sides (935,936) and bottom (934) of the lower camera shroud. They were prepared for transmission electron microscopy by first hand-grinding with abrasive paper to a thickness of 0.006". The edges were lacquered and the sample electropolished in 10% perchloric methanol using the “window” method, to a thickness of ~0.001". Final thinning was accomplished by polishing 3 mm punched disks in an acetic-phosphoric-nitric acid solution.

Paper 2: Hydrodynamic Stability of the Flow between Eccentric Rotating Cylinders with Axial Flow: Visual Observations

The influence of side leakage on the onset of Taylor vortices in high-speed journal bearings is studied by observing the effects of varying the eccentricity of, and the axial flow through, an annulus. The apparatus permits of both sharp and smooth entries to the annulus. Flow visualization is achieved by means of aluminium paint pigment suspended in the test fluid. It is shown that both the eccentricity and the axial flow have a marked effect on the critical Taylor number. Evidence is presented for the co-existence of two systems of vortices within the annulus.

Paper 6: Hydrodynamic Stability of the Flow between Eccentric Rotating Cylinders: Visual Observations and Torque Measurements

The effect of varying the eccentricity on the appearance of Taylor vortices in journal bearing oil films, and the subsequent transition to turbulent flow, has been studied by means of visual observations and torque measurements.The vortices have been made visible using a suspension of aluminium paint pigment in the fluid, and also by dye injection, in an apparatus having a perspex outer cylinder.When the cylinders are eccentric, transition from laminar to turbulent flow is observed to proceed in four stages, an additional instability being present when compared with the concentric cylinder case. Only the second of these transitions causes a distinct change in the slope of the torque–speed characteristic.

The Hive Environment in Hot Climates

SUMMARYThe environment of an apiary on bare ground is about 5° C. hotter in summer than the shade air temperature, which in Western Australia frequently exceeds 32-2° and is commonly over 37-8°. The most effective protection of colonies from very high temperatures when shade is not available was found to be the use of white paint on all external hive surfaces. The use of aluminium paint gave higher hive temperatures. Substantial benefit was obtained also from top ventilation up to 58 sq. cm., and by avoiding a deep entrance; entrances 5 cm. high increased the hive temperature.

Aluminum Paint for Use at High Temperatures

Aluminum Paint for Use at High Temperatures

The Biology of the Brown-banded Cockroach and its Relative Susceptibility to Five Organic Insecticides

Laboratory studies were made on the biology of the brown-banded cockroach, Supella supellectilium (Serville), and its relative susceptibility to the insecticides, aldrin, chlordane, DDT, heptachlor, and lindane. Biological studies revealed the average preoviposition period for 19 adult females was 17.7 days. An average of 10 egg capsules were produced per female, while the period between capsules averaged 9.8 days. As many as 29 capsules were deposited by a single female, and about one-third from each female hatched. The incubation period of 14 capsules obtained from seven different females averaged 58.4 days. The maximum number of nymphs to hatch per capsule was 18, with an average of 12.8 for all capsules considered. The average length of adult life of 20 females was 115 days. The number and duration of instars were determined by labeling the nymphs with aluminum paint. The total number of instars of 37 nymphs varied from seven to nine, with seven being most commonly found. Significant variation in the duration of instar periods was shown in nymphs from three different females. The total period of nymphal development of 37 nymphs averaged 89.7 days. Toxicity tests were performed on female cockroaches selected immediately after they had emerged as adults. The insecticides were applied topically as emulsions between the prothoracic coxae. The results from these tests show that the brown-banded species does not differ greatly in susceptibility from the German cockroach ( Blattella germanica (L.)) and that the compounds tested can be arranged in the following descending order of toxicity, based on LD50 and LD90 values: lindane, heptachlor, aldrin, chlordane, and DDT.

Aluminum paint and powder

Aluminum paint and powder

Thirty Years' Experience In Testing Aluminum Paint Performance

Abstract Descriptions and illustrations are given of the results achieved with coatings of various kinds, including different formulations of aluminum paint on steel and aluminum bases at the Alumi...

The ignition of inflammable gases by sparks from aluminium paint and rusty steel

AbstractIn certain circumstances steel coated with aluminium paint can emit sparks when struck with a metal striker, and such sparks may ignite mixtures of inflammable gases or vapours in air. The sparks are due to the thermite reaction between iron oxide and aluminium, and therefore are produced only in the presence of iron oxide. The extent of this hazard depends on the nature of the paint; it is increased if the painted steel is subjected to heat.This work was therefore carried out to determine the effect of the nature of the paint, and the temperature to which the paint might be subjected in use on the tendency to produce incendive sparks (i.e. those liable to ignite inflammable gases or vapours).The investigation was divided into two sections, the first dealing with certain preliminary studies on the conditions necessary for the production of sparks and the reaction involved in spark formation, and the second consisting of a survey of the possible hazard with a representative series of commercial paints.No exact correlation between paint composition and liability to emit sparks was obtained, but none of the commercial oil‐bound paints tested gave sparks unless the specimen had been heated to at least 150°.The paper includes a note by the Senior Chemical Inspector of Factories, outlining the practical application of the results.

Zinc Poisoning in a Trout Hatchery

Natural acid waters will dissolve zinc from galvanized-iron pipes. In some acid waters with a very low mineral content 0.01 p.p.m. dissolved zinc is toxic to brown and rainbow trout ova and alevins. All stages in the life history of rainbow trout are more susceptible to zinc poisoning than corresponding stages of brown trout. The lethal concentration normally decreases with the age of the fish, but considerable variations have been recorded amongst ova, aievins, fry, and fingerlings. Survivors from batches of fish subjected to dissolved zinc are less susceptible to further toxic concentrations than are specimens that have not previously been in solutions of zinc. Under certain conditions mortality amongst trout fingerlings, due to einc poisoning, will occur after they have been in a zinc vessel for 15 min. The effects of zinc poisoning may not be immediately apparent. When removed from zinc-contaminated to relatively zinc-free water trout may appear normal but death may occur within 48 hr. In well-aerated water, little or no flow is necessary for the development of trout ova, which will develop normally in distilled water. Aluminium paint does not normally protect an underlying metal from the action of acid water. Zinc is an unsuitable material for use in a hatchery with an unbuffered water supply. The lethal temperatures for acclimatized brown (Salmo trutta L.) and rainbow (Salmo gairdnerii Richardson) trout fingerlings in Victoria are 20–30°C. For adult fish the temperatures are 27–29°C. A self-cleaning hatchery inlet screen and a spray jet for circular ponds are described. In hot cliaates the temperature of water entering a pond through a spray jet is less than that of water entering through a normal radial-arm jet.

ON THE COATING OF ALUMINUM ALLOYS

What I wish to recommend as the excellent coating process of aluminum alloys are as following: 1) For the small-size and large-size products, the three-step coating process of the special primer, zinc chromate-phthalic resin enamel and phthalic resin enamel (or aluminum paint) is the best.2) For the small-size product, the good process is to paint the zinc chromate-phthalic resin enamel, next the phthalic resin enamel on aluminum alloys which were electro-oxidized or treated with the phosphoric acid-alcohol solution.Several experiments brought me to the adoption of these above coating process.

Warmth Without Weight

For years the heat insulating properties of certain types of metallic coatings have been recognized by engineers and applied in the construction field, a well known ex ample being the use of aluminum paint as a coating for gasoline storage tanks. However, the application of heat reflecting coatings to textiles for the purpose of in sulating against the inflow of cold or the escape of heat from within is a comparatively recent development. The following digest of an article* by Professor Kirkpatrick gives some of the results of his laboratory tests in which the experimental evidence indicates that a reflective film of negligible weight will compare favorably with conventional textiles in restricting heat loss, and that by proper construction it should be possible to in crease the warmth and at the same time decrease the weight of articles of clothing, blankets, bedding and the like.

ARC-WELDED ROTARY DIAPHRAGMS FOR REDUCING APERTURE

advantage of reducing the aperture of large telescopes for visual observations of the details of the brighter planets is still a debated question. However, during the present season while Mars has been low and atmospheric conditions, rarely steady at Chabot Observatory, have been disturbed by several heat waves, we have found diaphragms a distinct advantage. Members of the Eastbay Astronomical Association, many of whom are skilled amateurs, and the casual visitors all agree that the reduced apertures give the most satisfactory views of the planets under average conditions here. Mr. Alfred Leach, who by trade is a skilled electric arc welder, and also an amateur who has an all-welded telescope1 with which he has done very creditable observing of Mars, proposed, designed, and made a set of diaphragms for the 20-inch refractor at Chabot Observatory at his own expense. His design is so simple and so successful that others may be interested. 20-inch refractor, now resplendent in a coat of WPA aluminum paint, is shown with the entire assembly, which weighed before attachment to the telescope about twenty-five pounds. Mr. Leach's description follows : The diaphragms installed by me in September, 1939, on the 20-inch refractor permit the instrument to be used at full aperture or with a 14-inch or 8-inch opening by turning a knob at the observing end. focal length of the 20-inch refractor is 28 feet. reduced aperture and the long focal length gave details on Mars not observable with full aperture. The diaphragm material is 22-gauge black iron. diaphragms revolve in front of the dewcap actuated by a j^-inch steel rod extending the entire length of the tube to the observing end. Here there is a steel disk six inches in diameter with three notches on the rim into which a spring-actuated rod drops

Aluminium paint and powder. By J. D. Edwards. 2nd ed., revised and enlarged. Pp. 216. New York: Reinhold Publishing Corp.; London: Chapman & Hall, Ltd., 1936. 22s. 6d

Aluminium paint and powder. By J. D. Edwards. 2nd ed., revised and enlarged. Pp. 216. New York: Reinhold Publishing Corp.; London: Chapman & Hall, Ltd., 1936. 22s. 6d

Construction and Behavior of a High Voltage Cylindrical Condenser

Cylinders of lumite glass 35 inches long by 10¼-inch diameter (such as are used on gasoline filling-station pumps) were used for dielectrics, and 0.005-inch aluminum foil for plates. A 7-inch glass margin was left at the ends of the cylinders. Each condenser had a capacity of 0.012 microfarad and would withstand steady voltages of over 100 kilovolts without ``flashing over.'' Sets of rings of 516−inch copper tubing were made to fit the cylinders at the edges of the plates, both inside and out. The rings provided a ``curled'' or ``rounded'' edge, in place of the rather sharp edge of the foil itself. The effect upon the ``edge corona'' and ``flash-over voltage,'' due to various-width bands of aluminum paint on the glass surface adjacent to the metal-plate edges, was tried, with and without the above-mentioned rings, in disruptive discharge and steady-voltage tests. The results showed that the highest voltages could be obtained, without break-over occurring, when the glass margins were chemically clean. It was also found that the best type of plate-edge construction was either the plain aluminum-foil edges without paint, or the curled edges (i.e., with copper rings) with a ¼-inch band of paint.

(1) The Journal of the Institute of Metals (2) The Journal of the Institute of Metals

(1) THIS volume comprises the metallurgical ab stracts which have already been circulated to members of the Institute of Metals during 1933 in the monthly Journal. The whole range of metallurgical science and practice has been covered in the usual compre hensive manner. Besides the structure and properties of metals and alloys and the metal working processes, a wide variety of topics, from the electron theory of metals to the uses of aluminium paint, are covered in abstract form in this volume. An imposing list of abstractor's names is given, but a list of the periodicals abstracted would be much more useful. (2) The thirteen papers presented at the March meeting of the Institute, together with Dr. H. Moore's presidential address and Prof. E. K. Rideal's May lecture on “Gases and Metal Surfaces” are now avail able as vol. 54 of the Journal. Prof. Rideal gives a lucid survey of recent advances in the physico-chemical study of the adsorption of gases by metals, in the course of which it is possible to discern several pointers to future methods of study of lattice structure. One of the most interesting of the papers is that by Prof. Portevin and Dr. Bastien on “Cast-ability of Ternary Alloys”, a subject of great practical importance in foundry practice which is slowly but steadily being investigated on sound physico-chemical lines. Research on the phenomenon of fatigue is represented by a communication from the National Physical Laboratory dealing with the influence of the intercrystalline boundary on fatigue characteristics. Other topics include the constitution of copper-iron-silicon alloys, magnesium-nickel alloys, and silver-beryllium alloys. The volume concludes with a full appreciation by Prof. Hanson of the late Dr. Rosenhain, a past-president of the Institute and the greatest modern exponent of physical metallurgy.

Protective Effect of Iron and Copper in Infectious Anemia of the Rat.

Pure iron, alone or in combination with a small optimum dose of copper or other catalytic metals, or combined with ultraviolet rays, is able to prevent and cure nutritional anemia in the weanling rat when fed upon a diet of whole milk for a period of 6–9 weeks., A similar preventive effect of both iron and copper has recently been advanced by Perla and Marmorston-Gottesman against the anemia of the splenectomized rat produced by Bartonella infection. It was further suggested by these investigators that the so-called nutritional anemia of the white rat may be complicated or influenced by a spontaneous infection of the animal with Bartonella. Perla observed that the addition of copper, either when fed or injected, to an adequate diet for a period of 10 days prior to splenectomy and 1 month thereafter protected 75% of their animals against the anemia, while iron, under similar conditions, protected against anemia in 50% of the animals. It was stated that copper is essential with iron in hemoglobin regeneration in rats suffering from nutritional anemia and also that an excess of copper plays a role in the mechanism of resistance to Bartonella muris anemia in the rat after splenectomy. The following work was undertaken to compare the effect of both iron and copper in this infectious anemia with their action in nutritional anemia. Eighty animals were kept in large galvanized iron cages recently painted with aluminum paint and fed with Purina Dog Chow which represents the standard food for our stock animals in this study. Groups of 10 animals were usually kept together in one cage so as better to expose them to the possibility of infection. Four cages with 20 adult and 20 young rats served as control. In order to avoid mistakes due to irregular intake of metals by the animals, the colloidal copper and iron preparations were administered by intraperitoneal injection. To omit trauma the injections were given every fifth day commencing 10 days previous to splenectomy and subsequent thereto for one month. 2.5 mg. of the iron were given to the first group; 2.5 mg. of iron-copper solution were given to the second group; 0.25 mg. of the copper solution were given to the third group which corresponds to a daily dose of 0.5 mg. iron and 0.05 mg. copper, doses which proved optimal in the treatment of nutritional anemia. These doses are one-half those used by Perla. One group of 10 rats was exposed daily for 30 minutes to the rays of the General Electric Sunlight Mazda Lamp, Type S-I, (at a distance of 4 feet) which has been used in previous experiments.

Roofs made of Sheet Steel

A NOVEL application of electric arc welding has recently been begun in the United States. Roofs are made of long strips of sheet steel which are assembled and welded on the ground and then hung up between the top and bottom of the roof. The shape in which they hang is approximately that of a catenary and they are welded together. In the Electrical Review of August 25 a description is given of the ‘self-supporting’ roofs erected on four huge grain elevators at Albany, New York. These roofs are watertight and have no columns or stanchions to support them. Maximum storage capacity is thus obtained. Each roof measures 288 ft. wide with a total span of 140 ft. and is composed of 76 steel sheets 140 ft. in length and 50 in. wide. The lower support of the roof starts approximately 22 ft. above ground level and extends upward at an angle of 30-40. Both the top and bottom supports were constructed at an angle to conform with the slope of the roof. By welding in various ways, expansion and contraction troubles are avoided. Small expansion joints were welded at suitable places over the longitudinal spans so as to allow free expansion for the roof. On completion, the roofs were given two coats of red lead and one of aluminium paint. With eight operators the speed of welding averaged 50 ft. per hour. More than 400 tons of sheet steel of No. 12 gauge were used.

Developments in the Stabilization of Painting Practice for Wood

Abstract Painting practice is changing from a craft to a part of engineering. The Forest Products Laboratory has tested the painting characteristics of softwoods. The tests included edge-grain and flat-grain boards, light woods consisting mostly of spring-wood and heavy woods with wide bands of summer-wood, white lead and prepared paint, various combinations of paint, linseed oil, thinner, and drier for the priming coat, and aluminum paint as a first coat. Conditions of dryness and of humidity entered into the tests. The basic factors responsible for the chief uncertainties of paint behavior were studied, and the way is pointed for a possible stabilization of painting practice for wood through further research.

Aluminium bronze powder and aluminium paint. By J. D. Edwards. Pp. 104. New York: The Chemical Catalog Co., Inc., 1927. $3

Aluminium bronze powder and aluminium paint. By J. D. Edwards. Pp. 104. New York: The Chemical Catalog Co., Inc., 1927. $3