Mold (manufacturing)

“ The molds must be very freely vented, and not only at the joint of the mold, but by using the vent wire freely through the body of the mold itself; in fact, for brass the venting would be considered excessive. With aluminum it is, however, necessary to get the air off as rapidly as possible, because the metal soon gets sluggish in the mold, and unless it runs up quickly it runs faint at the edges. ”

“ When finally assured of this fact, take out the mold, open it, and blow it out, to make sure of absolute cleanness. Close and bind again and place on a hearth of fine, hot sand. The mold should still be glowing when the casting is made. The ladle should contain plenty of metal, so as to hold the heat while the casting is being made. The presence of a little zinc in the metal ensures a sharp casting. Finally, to ensure success, it is always better to provide two molds in case of accident. Even the most practiced metal molders take this precaution, especially when casting delicate objects. ”

“ The molds are made in part the same as when of brass, and out of tin that contains as much hardening as possible. The hardening consists of antimony and copper. This metal mold must be painted over several times with Spanish red, which tends to prevent the metal from melting. The metal must not be used too hot, otherwise it will melt the mold. ”

“ Mold can grow on virtually any organic substance. Most buildings are full of organic materials that mold can use as food, including paper, cloth, wood, plant material, and even soil. In most cases, temperature is not an issue; some molds grow in warm areas, while others prefer cool locations such as bread stored in a refrigerator. Often, more than one type of mold can be found growing in the same area, although conditions such as moisture, light, and temperature may favor one species of mold over another. ”

“ Butter is not well suited to the growth of mold, but the paper used for lining the tubs, or wrapping the prints is an excellent medium for mold growth. The wood of the tub also furnishes ample food for this type of life, especially where the wood contains any sap. One other essential condition for mold growth is a supply of oxygen. The mold spores are widely disseminated, and are always to be found on the butter tubs and on the paper. ”

“ The first step in the process is the preparation of the mold. The substance originally used for the construction of this was plaster of Paris. This substance is, however, porous and must be rendered impermeable. The materials most commonly used of later years are stearine, wax, marine glue, gelatin, india rubber, and fusible alloys. With hollow molds it is a good plan to arrange an internal skeleton of platinum, for ultimate connection with the anodes, in order to secure a good electrical contact with all parts of the mold. ”

“ The funnel of the clay mold is filled with pieces of metal, and the entire thing is buried in the fired charcoal. In fifteen minutes the metal melts and runs down through the gate at the bottom of the funnel into the hollow, wax-lined mold. Since the entire mold is hot, the metal does not cool or harden promptly, and the pipe maker taps and jars the mold in order to make the metal penetrate and fill every part. ”

“ Shellac the surface of the top mold, cleaning away any small bits of plaster around the edges. Trim down the box so that the top mold projects over it about 3⁄8 in., making it easy to drop the top mold into place over the bolts. To use the mold, make certain that it is clean inside and set the top into place. Fasten down the wing nuts at the washers. Be very careful that the mold is dry, as hot metal poured on a wet surface may cause a dangerous splash. ”

“ Permanently cast metals generally show 20% increase in tensile strength and 30% increase in elongation as compared to the products of sand casting.
The only necessary terrestrial input is the coating applied before each casting. Typically, permanent mold casting is used in forming iron-, aluminum-, magnesium-, and copper-based alloys. The process is highly automated and state-of-the-art easily could be adapted for use in an extraterrestrial manufacturing facility. The main disadvantage is that the mold is not easy to design or produce automatically. ”

“ Gouge the metal out with a knife a little at a time.
Do not remove the mold keeper from the mold. The mold keeper is for the purpose of holding the lugs of the matrices in alignment. If it is removed and not replaced properly, it will interfere with the proper alignment of every line set.
Keep the face of the mold clean and free from metal which has a tendency to accumulate during the day while the mold is being used. A clean face of the mold will greatly facilitate the press make-ready. Metal on the mold causes high and low letters on the slug. ”

“ The metal instantly solidifies in the mold, forming the slug or linotype, having on its edge raised type characters formed by the matrices. The mold wheel next makes a partial revolution, turning the mold from the original horizontal to a vertical position in front of the ejector, which then advances from the rear through the mold, pushing the slug out of the latter into the receiving galley, at the front. ”

“ Plaster Molds.—Castings of any metal can be done in a plaster mold, provided the mold has dried, at a moderate heat, for several days. Smoke the mold well with a brand of rosin to insure a full cast. Where there are only one or two ornaments or figures to cast, it may be done in a mold made out of dental plaster. After the mold is made and set enough so that it can be taken apart, it should be placed in a warm place and left to dry for a day or two. When ready to use the inside should be well smoked over a gaslight; the mold should be well warmed and the metal must not be too hot. ”

“ Then, I surmise, he built up roughly a clay mold, well sanded, pressing what was left of his fabric into the inside of this mold as he built his vessel upward. Frequently, doubtless, the fabric was not sufficient to go to the top, which explains why sometimes only a part of a jar shows the cord markings. The jar completed, it was easy to pull away the upper mold shell of clay and by means of the fabric lift the vessel out of the mold hole and remove it to the drying spot, where the fabric was peeled off and handles or other projecting parts added. ”

“ A mold can be made in two pieces of a round object like a ball and if each piece is exactly one-half, it will draw, because there is no point under which the plaster will hold. Any hollows or projections will form "under cuts" necessitating making the mold in a number of pieces that it may relieve or be lifted off the cast. Molds of heads from which to cast paper forms are often wanted and are easily made. With the skinned head of a fox, let us say, on the table, the lower part is embedded in fine sand or clay about on a line with the mouth. ”

“ Radio Cabinet and Telephone Set of Molded Tar-Acid Resin.
Source: Bakelite Corporation, 217 Park Avenue, New York, N. Y.
[19]
A typical molding powder or pre-form pellet will contain by weight:
The molding of tar-acid resins.
Ordinarily the molds used are made of hardened steel, highly polished. They must stand working pressures of several thousand pounds per square inch. The mold is placed in a hydraulic press, heated by steam, electricity, or gas, and the molding material is placed in the mold. The press is closed and heat and pressure are applied. ”

“ Commercial firms that do mold remediation work or work on water- and fire-damaged buildings often use large fans, dehumidifiers, and other equipment to dry wet buildings and items quickly before mold has a chance to grow. ”

“ Therefore we may expect to find instances where a process consuming the resin in quantity and resin manufacture are both performed by the same company provided other conditions (such as the patent situation and knowledge of the art of manufacture) are favorable.
Tar-acid resins for molding.—The present practice of molding resins is favorable to large-scale production. The shaping of the mold is expensive, involving skilled labor upon hardened steel; but once the mold is made it may be used to produce tens or hundreds of thousands of units. ”

“ In most cases, if visible mold is present, sampling is unnecessary.
The most important sign of a mold problem is visible mold. If mold is found during a building investigation, the size and extent of the moldy area should be determined. Information on the water or moisture problems that allowed the mold to grow should be evaluated, in part because areas of hidden mold may surround the areas of visible mold. ”

“ Nonexpendable mold casting, on the other hand, relies less on the conditions of gravity and pressurized atmosphere. The molds tend to last for a greater number of runs. The main disadvantages are that (1) production devices tend to be large, on the order of tons, and (2) the processes are more complicated than for expendable mold casting. ”

“ Butter may mold where the tubs have been thoroughly treated, because of the mold spores on the paper used for the lining. One of the black molds is able to thrive on parchment paper whenever the air is damp. ”

“ The old-time method of casting type was with hand molds, the melted metal being poured in at the foot of the mold with a small ladle while the mold was held in the hand. In the modern casting machine, the mold with its matrix, is assembled by the side of the metal pot, in which the metal is kept at a uniform temperature by means of a gas furnace. ”

“ This slimy coat below the mold layer is made up of diverse species of bacteria and fungi that are able to grow after the acid is reduced by the blue mold. The organisms in the red slimy coat act upon the casein, producing an alkaline reaction that is unfavorable to the growth of the blue mold. Two sets of organisms are, therefore essential in the ripening process, one preparing the soil for the ferment that later produces the requisite ripening changes. ”

“ The examination for mold is made with the ×6 ocular and 16 mm objective, giving a magnification of approximately 90 times. About 50 fields are supposed to be examined and the result expressed in terms of the per cent in which mold was found. It is stated that it is believed that manufacturers can conduct their operations so that mold will not be present in more than 25 per cent of the fields. There are, therefore, three units in which to express the results: bacteria in cubic centimeters, yeasts and spores in one-sixtieth of a cubic millimeter, and molds in percentage of microscopic fields. ”

“ With a sharp knife trim off all ragged edges and superabundant plaster, leaving your mold small as possible, and lighter to handle. These leaf molds are much better for all uses, even for sheeted wax flowers, than those metal molds that cut the wax, and never give the fibrous look needed for a natural looking leaf. The lily of the valley needs a wooden mold, the flower is so delicate a plaster mold cannot be made. ”

“ It is impossible to describe just how hard a mold should be rammed, but by observing the results the beginner can tell when a mold is too hard or too soft, and thus judge for himself. If the sand falls out of the flask when lifting the cope, or if it opens up or spreads after it is poured, it shows that the mold has been rammed too little, and if the surface of the sand next to the pattern is cracked it shows that the mold has been rammed too hard. It will be found that the edges of the mold can stand a little more ramming than the middle. ”

“ Before planning a remediation effort, the size and extent of the mold problem and any continuing moisture problems should be assessed. A remediation generally can be divided into small (less than 10 square feet of mold) , medium (10‐ 100 square feet of mold) , and large jobs (more than 100 square feet of mold) . www.epa.gov/mold/moldcourse/chapter4.html#4.2
Question 4: Answer: “A” TRUE
Remediating mold and moisture problems may be complex, and it may increase workers' exposure to mold unless personal protective equipment (PPE) is used. ”

“ Such treatment insures, of course, a very rapid growth of these plants, inside as well as outside. Most commonly, however, the cheese-maker depends upon his straw mats for the molds, and expects them to grow chiefly on the surface. The molds which develop in the cheese are not all of the same species. The common blue mold is most usual, but most cheeses are not properly ripened until several species of molds grow together within them. ”

“ Those familiar with electrotypes well know the superiority of the wet black leading process, especially for half-tones, stipple, Ben Day or fine type, where much of the detail and sharpness is lost in dry black leading, because of the crushing effect the brushes have on the wax mold. In this new type of black leading machine this fault is entirely eliminated, as the brushes never come in contact with the printing face of the mold; they merely polish the high built-up spots, thereby insuring better electrical conductivity to the wax, and a more uniform deposition of the copper shell. ”

“ Subsequent labor upon the molded product is usually limited to the simple task of smoothing the line where the flash is broken off, since the product comes from the mold in the color and with the surface and shape desired. ”

“ Mold can generally be removed from hard surfaces by wiping or scrubbing with water and detergent. Always follow the cleaning instructions on product labels. Surfaces cleaned by damp wiping should be dried quickly and thoroughly to discourage further mold growth. ”

“ The tar-acid resins were first developed for molding and they are still used in large volume in this way. An article produced in large quantity is more likely to be made of molded resin. The cost of the mold, which may amount to several thousand dollars, then becomes very small per unit produced. If the article is of such a shape that it would require a great deal of labor to produce in metal or wood, it may be produced in quantity much more cheaply from resin, since it will come from the mold almost in finished form. ”