Cob blasting was really popular in the late 90’s on into the mid 2000’s, so there’s a lot of information out there on it. The premise is simple; use ground up corn cob grit material in a traditional sand blaster to blast stain off of logs and do less damage than sand.
While corn cob does do less damage than sand, it has it’s own drawbacks.
It smells, especially after it gets rained on. The odor is similar to dog feces. Not nice. This is one of those cases where the marketing of corn cob blasting really stretched to the point where they were pushing the product as biodegradeable. Usually this is a great feature, but not when its spread all around your house 6-8 inches deep. Aaand that brings us to the second flaw.
It’s light weight. This is supposed to be the feature of corn cob blasting that allows the corn cob to cause less damage to the wood than sand. In reality, we’ve found through extensive real world testing that the grit size makes a much bigger difference in the amount of texture you get from blasting than the weight of the media.
Unfortunately, since corn cob is so light, this means that it takes a high volume of it to blast your house. For instance, 50 lbs of media will blast around 100 square feet, whether its corn cob grit, or crushed glass. The two different media come in bags that are vastly different in size. Corn cob grit is more than twice as large a bag for the same weight, and that means large drifts of cob grit around your house that needs to be moved away to degrade somewhere else.
With other heavier, finer materials, we can create less of a mess, and often much of the media simply disappears into the ground.
It’s organic. That sounds great, but that means it can also carry organic stuff like mold and bacteria to the logs and possibly inside your home. With the speed of impact, it can even mean that its bringing mold and mildew spores into the surfaces of your logs, and most stain manufacturers warn against that.
We used corn cob grit for a few years back in the early 2000’s, but have since found several other blasting medias that give us superior results.
Call us and we’ll discuss your project and what will work best for your needs.