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GRID MOLD TOUCH-UP SPRAY PROCEDURE
After a mold has been running for several hours, it may need corking; however, it may not need a complete cork job. A touch-up will add hours to an original cork job and save you minutes of work. Several different touch-ups can be applied to the mold depending upon existing conditions. The type of touch-up needed will depend on the condition of cork on each mold half. This can be broken down further to gate and wire section condition of each mold half.
The gate will first show wear; cork may be completely gone in several spots. Usually cork will wear under the ladle pour holes. Cork may be completely gone and bare metal showing. If this is the case; the gate section, all the way down to the top frame of the grid, should be wire brushed with horizontal brush strokes. This brushing is to remove all cork left on gate because it has worn off unevenly. Cork should be brushed off gate areas on both halves of the mold.
The spray gun should be used with horizontal strokes. Use layer of cork about the same thickness as was applied with an original mold spray. This layer of cork will consist of approximately ten (10) passes with spray gun on each half. Gate touch-up need practice because cork must be applied evenly and in the gate section only. No cork should be in the wire section since this could cause flashing and plug up the vent bar. When the gate area is sprayed, top of the gate (angled part) should also be sprayed. Gate section should be wiped with clean piece of felt and top frame wiped with a wooden stick. This procedure covers a gate touch-up.
Another touch-up that can save you time is a light spray up. This consists of gate touch-up and light spray over the whole face of the mold, after old cork is scraped off the mold surface with a putty knife. Remember to connect the vent bar air hose any time cork is applied to a vent bar area. Cork applied to the mold surface is about the same as sprayed on after the mold was scraped in the original spray up. This layer of cork is about two coats of cork; each coat consisting of about five passes with the spray gun. The mold bottom should again be cleaned off with a wire brush or putty knife up to the bottom frame. This touch-up may be needed only on one mold half. The moving half usually receives most cork wear.
Final touch-up consists of gate touch-up and the following: Mold should be brushed vertically with a wire brush. A very light brush stroke is used. All we want to do is remove burnt cork from inside the wires. Burnt cork is darker than normal cork. Remember, only a light brush stroke is needed.
Mold should be sprayed with about 3 coats of cork, after attaching vent bar air hose. Frame and lug areas should be wiped free of cork with a wooden stick. Another coat of cork is applied to the mold surface. Then the entire mold surface should be scraped with a putty knife. Apply final two coats of cork and the touch-up is complete except for cleaning the bottom of mold with a wire brush, and wiping the gate with a piece of felt.
Other small touch-ups consist of spraying small amounts of cork into the lug areas when holes appear in the lug center. Spray cork into the mold to fill in a spot where cork has pulled off. A spot where cork has pulled off may cause flash at that point.
Remember cork is an insulation, it helps the grid to fill in.
Leader pins on stationary mold half should be lightly greased each time the mold is corked. They should be greased with a non-residue forming high temperature grease. Leader pins should be covered with 2 pieces of 1" diameter pipe any time cork is applied to the stationary mold half. Never put an excessive amount of grease on leader pins because, if grease gets on the mold, cork will not stick. If grease is on the mold, read the section on washing molds.
Knockout pins should be lubricated once a day, with Bee’s was only. Although grease would work on the pins, grease must be kept away from the mold surface.
Extend pins by opening the mold. Bee’s was should be touched to the end of each knockout pin. Only a small amount is needed on each pin.
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