Corncob Information Overview Corncob particles are valuable because they are highly absorbent and they are abrasive. The various corncob products we offer are defined by the size of the particle and the portion of the cob from which they are made.
The largest particle is about one-fourth the size of a garden pea and the finest particles are flour-like in appearance. There are three parts to a corncob: Chaff, which is also called beeswing, is on the outside of the cob; Pith is the soft/spongy center portion; and Woody-Ring, which forms between the Chaff and Pith.
All three portions of the cob are absorbent, but the pith and chaff portions are the most absorbent. Those portions have a bulk density of approximately 8 pounds per cubic foot and that compares to about 27 pounds for the woody-ring. The difference in bulk densities allows separation of the woody-ring from the pith & chaff portions.  Products made from the woody-ring portion are referred to as "grit" products and products made from pith and chaff are referred to as "PC" products.
Both Grit products and PC products are: all-natural; bio-degradable; renewable, and absorbent. However, water absorbency for PC products can approach 300% on a weight-to-weight basis and that compares to grit products at about 100%. Corncob particles are free-flowing and that combined with their absorbency makes them ideal for use as a "carrier" of other products. In general, those products are liquid in form and they are absorbed by the corncob particles. Examples of carrier applications include carrying the active ingredients of pesticides, animal medications, feed flavors, and feed nutrients. Grit particles are also used when the abrasive characteristic of corncobs is desirable. Corncob grit is often characterized as being a "soft abrasive" because it is considerably less aggressive than other abrasive media. In tumbling and vibratory finishing applications, the primary purpose for using corncob grit is to dry metal parts, but corncob grit also de-burrs and polishes the parts at the same time. The grades most often used are 1014, 1420, and 2040 and the correct grade is usually the one where particles do not lodge in holes or cavities present in the parts. As a pressure blast media, corncob grit is ideal for wood and aluminum substrates because it is considerably less aggressive than sand. Corncob grit is also non-sparking and does not foul bearings. In general, larger grit particles are more aggressive than smaller particles. Grit blasting can utilize grades 1014, 1420, 2040, or 3080. Because the particles are larger, 1014 and 1420 are the most aggressive. Log homes are most often grit-blasted with 2040 or 3080 and of those two, 2040 is larger and is therefore more aggressive. We recommend, from experience, 20/40 grit as the best option for cob blasting log/wood homes for restoration and refinishing purposes! 
 2040 Grit
The corn cob we recommend for cob blasting log/wood homes
2040 Grade is the finest of the three common industrial grades (1014, 1420, 2040). Tumbling and vibratory finishing are ways it is commonly used. It is also used as a blasting media for restoring logs/wood, by removing the failing finish/damaged wood cells, and opening up the pores of the wood (slightly texturizing) creating the best surface for the new stain, and allowing the cob blasted wood to take on up to 50% more stain i.e. more protection for the logs/wood. The 2040 is also used as a "carrier" of animal nutrients or feed flavors. In general, 2040 would be the largest particle used as an ingredient in animal feed and it would be about the smallest particle used as a pesticide carrier. Bulk Density: 21 - 26 pounds per cubic foot
Moisture: Not more than 8% Cost per 40lb bag: $14.95
Cost per 2000lb skid: $747.50 (sales are by the full skid only)
Shipping: The cost of shipping will be invoiced separately - it is not included in the product cost. There are 50 bags per skid, and up to 20 skids can be loaded on a single truck shipment. For a full truck shipment, simply make two separate purchases of 10 skids. Please email us for a shipping quote.  1014 Grit
1014 Grade is the largest of the three most common industrial grades (1014, 1420, 2040). It is commonly used in tumbling and vibratory finishing. Polishing brass bullet casings is a common application. It is also used as a blasting media, but usually for hard substrates such as steel and concrete. In general it would be too aggressive for wood. Density: 26 - 32 pounds per cubic foot.
Moisture: Not more than 8% Cost per 40lb bag: $14.95
Cost per 2000lb skid: $747.50 (sales are by the full skid only)
Shipping: The cost of shipping will be invoiced separately - it is not included in the product cost. There are 50 bags per skid, and up to 20 skids can be loaded on a single truck shipment. For a full truck shipment, simply make two separate purchases of 10 skids. Please email us for a shipping quote.  1420 Grit
1420 Grade is the medium-sized particles for the three common industrial grades (1014, 1420, 2040). It is used in the same applications as 1014. The selected grade is usually determined by evaluating the likelihood of particles passing through or getting caught in cavities or holes in the parts being mass-finished. It can also be used as a blasting media, and like 1014, it is probably too aggressive for most wood substrates. Density: 26 - 31 pounds per cubic foot.
Moisture: Not more than 8% Cost per 40lb bag: $14.95
Cost per 2000lb skid: $747.50 (sales are by the full skid only)
Shipping: The cost of shipping will be invoiced separately - it is not included in the product cost. There are 50 bags per skid, and up to 20 skids can be loaded on a single truck shipment. For a full truck shipment, simply make two separate purchases of 10 skids. Please email us for a shipping quote.  40 Grit
40 Grade is typically used as a "carrier" for flavors, nutrients, or medications for animal feed. The minus sign used to describe this grade indicates that the vast majority of particles pass through, or are below, a #40 test sieve. The particles are like powder in appearance. Bulk Density: 17 - 26 pounds per cubic foot.
Moisture: Not more than 8% Cost per 40lb bag: $14.95
Cost per 2000lb skid: $747.50 (sales are by the full skid only)
Shipping: The cost of shipping will be invoiced separately - it is not included in the product cost. There are 50 bags per skid, and up to 20 skids can be loaded on a single truck shipment. For a full truck shipment, simply make two separate purchases of 10 skids. Please email us for a shipping quote.  1/4" and +8 Grit
+8 Grade is also known as 1/4" Grade and it is the largest particle offered. +8 usually indicates an industrial application where the particles are used as a mass-finishing media in a tumbling or vibratory finishing application. 1/4" usually indicates an animal bedding or bird litter application. For +8 grade, the vast majority of particles pass through a 5/16" screen and are retained on a # 8 screen. Bulk Density: 21 - 27 pounds per cubic foot.
Moisture: Not more than 10% Cost per 40lb bag: $14.95
Cost per 2000lb skid: $747.50 (sales are by the full skid only)
Shipping: The cost of shipping will be invoiced separately - it is not included in the product cost. There are 50 bags per skid, and up to 20 skids can be loaded on a single truck shipment. For a full truck shipment, simply make two separate purchases of 10 skids. Please email us for a shipping quote. |
