Rock tumbling is a rewarding hobby, transforming rough rocks into beautiful, polished treasures. A key element in this process is Rock Tumbler Grit, the abrasive material that smooths and shapes your stones. Understanding how grit works, the different types available, and how to use them effectively is crucial for successful rock tumbling. This guide will answer common questions about rock tumbler grit, providing you with the knowledge you need to achieve professional-looking results.
Understanding Rock Tumbler Grit Sizes
Rock tumbler grit comes in various sizes, each designed for a specific stage of the tumbling process. These sizes are measured in mesh, referring to the number of openings per linear inch in a screen. A higher mesh number indicates a finer grit with smaller particles. The most common grit sizes used in rock tumbling are:
- Coarse Grit (60/90 Mesh): This grit is used in the first stage of tumbling to shape and smooth rough rocks. Its large particles remove sharp edges and initial imperfections.
- Medium Grit (120/220 Mesh): Following the coarse grind, medium grit further refines the shape of the rocks and removes scratches left by the coarser grit.
- Fine Grit (400/600 Mesh): This grit smooths the surface of the rocks in preparation for polishing. It removes fine scratches and prepares the stones for a high shine.
- Pre-Polish Grit (1000 Mesh): While not always necessary, a pre-polish grit can be used after the fine grit to further refine the surface before polishing, especially for softer stones. (See “Would I Get a Better Polish with a 1000 Grit Step?” below)
Grit sizes
Common Questions About Rock Tumbler Grit
This section addresses frequently asked questions about rock tumbler grit, offering practical advice and expert insights.
Can Sand Be Used as Rock Tumbler Grit?
While sand might seem like a readily available alternative to rock tumbler grit, it’s generally not recommended. Silicon carbide grit, the standard for rock tumbling, possesses superior hardness and sharp, angular particles ideal for abrasion. Sand, often composed of quartz, has the same hardness as many commonly tumbled rocks, rendering it ineffective for grinding. Additionally, sand particles are typically rounded, further reducing their abrasive capabilities. Using silicon carbide rock tumbler grit ensures efficient and effective smoothing and shaping of your stones. For a more detailed explanation, see our article: “Can I Use Sand Instead of Grit?”.
Sand vs Grit
What Does the “F” in Grit Sizes Mean?
Sometimes, rock tumbler grit sizes include the letter “F,” such as 500F. This designation signifies a finer grit size than the number indicates. For example, 500F is finer than standard 500 grit. “F” simply stands for “finer.”
500F grit
Can Rock Tumbler Grit Be Recycled?
Although technically some grit can be recovered after tumbling, recycling rock tumbler grit isn’t practical. The tumbling process breaks down the grit particles, reducing their size and effectiveness. The effort required to reclaim and clean the spent grit outweighs the cost of purchasing new grit.
recycling grit
Why Not Use Extra Coarse Grit for Faster Tumbling?
While it might seem logical that extra coarse grit (like 20 mesh) would accelerate the tumbling process, it often proves less effective than standard coarse grit (60/90 mesh). Although larger, extra coarse grit has fewer particles in the barrel, resulting in less overall abrasion. 60/90 grit provides a balance between particle size and quantity, maximizing grinding efficiency. Learn more about our experiments with extra coarse grit in our dedicated article.
Extra coarse grit
Is a 1000 Grit Step Necessary for a Better Polish?
For most rock tumbling applications, a final grind with 500 or 600 grit provides excellent results before polishing. A 1000 grit step, while potentially beneficial for extremely soft stones or competitive polishing, is generally unnecessary for achieving a high-quality polish. This ultrafine grit is expensive and adds extra time to the process with minimal improvement for most rocks.
1000 grit
Choosing the Right Rock Tumbler Grit
Selecting the right rock tumbler grit is essential for successful rock tumbling. By understanding the different grit sizes and their functions, you can achieve beautifully polished stones. Remember to start with coarse grit for shaping, progress through medium and fine grits for smoothing, and consider a pre-polish grit for softer stones before the final polish. Using quality silicon carbide grit and following recommended procedures will ensure your rock tumbling hobby yields stunning results.
