Tumbling brass casings in corn cob media is a popular method for cleaning and polishing spent brass, preparing it for reloading. However, the optimal tumbling time isn't a fixed number; it depends on several factors. This guide will explore these variables and help you determine the perfect tumbling time for your brass.
Factors Affecting Brass Tumbling Time in Corn Cob
Several factors influence how long your brass needs to tumble in corn cob media:
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Initial Brass Condition: Heavily soiled brass, with significant carbon buildup or corrosion, will require a longer tumbling time than relatively clean brass. Consider the level of cleaning needed—a light cleaning might only need a few hours, while heavily soiled brass may need up to 24 hours or even longer.
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Media Type and Quantity: The type and amount of corn cob media used significantly impacts the cleaning process. Finely ground media will clean faster but can potentially cause more scratching. A sufficient amount of media ensures proper agitation and even cleaning. Too little media will result in uneven cleaning and potentially damaged brass.
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Tumbler Type and Size: Different tumblers have varying rotational speeds and capacities. Larger tumblers may require longer tumbling times due to the increased volume of brass and media. The tumbler's speed also influences cleaning time; slower speeds may require a longer duration for thorough cleaning.
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Desired Level of Cleanliness: Your desired outcome influences the duration. Do you need a simple cleaning to remove surface dirt, or are you aiming for a mirror-like shine? For a deeper clean and polish, plan for a longer tumbling time.
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Additive Use: Adding a lubricant like NuFinish or a brass polishing compound can significantly enhance the cleaning and polishing process and affect tumbling time. These additives can speed up the cleaning or enhance the shine, potentially reducing overall time. However, overuse of additives can be counterproductive.
Determining the Ideal Tumbling Time: A Step-by-Step Approach
There's no one-size-fits-all answer. Experimentation is key to finding the ideal time for your specific setup. Here's a recommended approach:
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Start with a Test Batch: Begin with a small batch of your brass, aiming for a representative sample of the condition of your entire collection.
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Initial Tumbling: Tumble the test batch for 6-8 hours. Check the brass for cleanliness and shine.
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Incremental Increases: If the brass isn't sufficiently clean, increase the tumbling time by 2-4 hours increments, checking the brass after each increase.
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Observe and Adjust: Carefully examine the brass after each interval. Look for signs of over-tumbling, such as excessive wear or scratches. The goal is to achieve the desired level of cleanliness without damaging the brass.
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Document Your Findings: Keep detailed records of your experiment: the amount of media, additives used, tumbling time, and the outcome. This documentation will serve as a valuable reference for future tumbling sessions.
Troubleshooting Common Issues
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Brass still dirty after prolonged tumbling: Check the amount of media, consider using finer media, and ensure the tumbler is functioning correctly.
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Brass is scratched or damaged: Reduce tumbling time, check the media for sharp or abrasive particles, and consider using a less aggressive media.
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Uneven cleaning: Check the media-to-brass ratio and ensure even distribution of media within the tumbler.
By following these steps and considering the factors outlined above, you can determine the optimal tumbling time for your brass and consistently achieve excellent results. Remember, patience and experimentation are vital for success in brass tumbling.
