Techniques for Polishing With Corn Cobs
Corn cob granules used for polishing are made from the woody ring of the corn cob, which is the area between the innermost pith and the outermost chaff. According to Grit O' Cobs, corn cob granules are an ideal material for polishing, de-burring (removing sharp edges from metal through filing or mechanical action) and finishing metal, and have a Mohs hardness factor close to 4.5, which is similar to iron. Automotive parts, shell casings and cartridges, nuts and bolts, staples and buttons are some of the many disparate items that benefit from polishing with corn cob granules. Corn cob granules are available in varying sizes and are often used as a general absorbent.
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Vibratory Polishing and Finishing
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Vibratory finishing is often used on small metal parts such as gun casings and cartridges, jewelry and metal tools. To determine the proper size of corn cob granule to use, determine the smallest diameter of the part you want to polish and select a corn cob grade that is large enough so that it will not lodge into the smallest diameter of the piece. In addition to polishing, corn cob granules absorb oil and other liquids. Vibratory tumblers use constant vibration that causes the corn cob granules to continuously grind into the part to polish it and remove sharp edges. According to Grav Co, LLC, vibratory systems are used where precise polishing and deburring is needed, such as in the recesses of the bore of a gun.
Tumbling Barrel Polishing
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Tumbling barrels are drum-like enclosures that use rotational motion to de-burr and polish the part by constant friction against the corn cob granules. Corn cob media used in tumbling barrels is most effective for polishing brass and bronze and for drying and light polishing of metal parts.
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Grit Blasting and Polishing
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Corn cob grit blasting is done using a sand-blaster. Since corn cob grit is less abrasive than sand, it is referred to as a soft abrasive. Grit blasting using corn cob grit does not etch glass and is often used to clean and polish machinery containing electric motors.
Conclusion
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Corn cob media is a type of dry polishing compound that is processed to different size granules depending on the type of polish desired and type of material to be polished. Corn cob media is biodegradable and is safe to use in tumbling and vibratory media and also acts as a drying agent while removing oils and moisture.
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References
Resources
- Photo Credit Corn on the cob image by Jim Mills from Fotolia.com
