CHAPTER VI USING DIVISION PLATES BETWEEN SECTIONS OF FLASK TO MAKE THE PARTING As explained in a former chapter it is often necessary to make the flask and mold into quarter or eighth sections, and to make this possible division plates must be arranged to separate the sand mixture, without any possibility of its parting at a point it is not desired to have it do. These division plates may be made of any material that will serve the purpose; thin metal is best, as a strip or sheet of tin, sheet iron, or any metal that can be easily cut into the shape desired; this is cut so that it fits around the pattern; making a complete outline of the pattern, hence it fits up very closely to same, thus making the mold perfect in parting at all points. A thin tough cardboard can also be used; this is far better if treated with a waterproof coating; by dipping it in a pan of melted paraffine wax the cardboard is made impervious to the moisture in the sand and at the same time cannot adhere to the sand mixture in the least, thus insuring a smooth parting to the sections of 'mold. At (a) Fig. 4 is shown the method employed to divide either the upper or lower sections of flask into quarters; the division strips are cut so as to meet at a common point in the center of flask, and this center is held by small strips of paper or cloth pasted to the sides of the plates, in the manner illustrated, where cardboard is used for such plates. When tin or metal strips are used this center may be held with a small piece of wax, or by using a small block of wood and into same sawing two slots or saw kerfs at right angles to each other; these need not be over 3/4" in depth, and this block of wood thus sets down over the strips of metal used as plates, thus holding them accurately to the center. Any fastenings of this kind must be placed at the top, or close to the top of the flask, so that they can be very easily taken out before turning over the flask; thus with the block of wood it can be removed and the space filled with sand before reversing the flask; as the sand mixture will easily hold the strips in place when the flask is once filled. The division plates are set over the pattern in the manner illustrated at (a), when cut out; when the pattern can be divided as with a wood pattern, cut into quarters, the plates may set between the division lines of pattern, thus requiring simple straight strips as division plates, and the quarter sections of pattern acting as a block to hold the strips in place. The strips must be long enough so that they will go between the joints of flask on the outside, which holds them securely in position at that point. The mold in flask is separated by removing the corner that has the most simple part of design, first, the pattern is lifted slightly and the one quarter of mold is carefully drawn outward at the same time, so to release it from the pattern at the one movement, thus enabling the most intricate and deeply cut lines in pattern to be separated from the sand mold without injury to the molding surface. These metal or cardboard division plates may also be employed in making the parting between the cope and drag of flask, instead of using the graphite or other material. They are cut in outline of the pattern as shown in the drawing at (b) Fig. 4; the metal or cardboard division plate is made exactly one-half the size of the surface of flask; thus the two plates are cut in an outline of one-half of the pattern, from each edge of the plates, and when placed together permit the pattern to go between them in the manner shown at (c) Fig. 4; this allows the pattern to be in one piece and divides the mold so that the impression of but one-half of the surface of pattern is imprinted in each section of mold. Where the pattern is in one piece, the mold is made in the following manner: a box form the size of flask is built; this is in height exactly equal to one-half the height of the pattern, so that when this form is placed on a cover board |