How does dry ice blasting work? Well first, let’s define some terms. A contaminant is any substance that you want to clean off, or otherwise want gone. It could be anything from carbon dust to grease to oil to cocoa powder. When you clean a contaminant, you clean it off of a substrate, which is the surface or item you want to be clean when the whole process is over.
Dry ice utilizes the third law of thermodynamics, called sublimation. What is sublimation? It is the process by which a solid changes directly to a gas without ever becoming a liquid. It is this very rapid change (and subsequent expansion of about 800 times, in the matter of milliseconds) that makes the whole process work.
So, now that you know what sublimation is, and how it works, let’s talk about thermal shock. If a substance is sitting at room temperature, say, between 70 and 80 degrees, and you very rapidly (again, think milliseconds) cool it down significantly (dry ice is -109F, so by “cool” I mean close to -109F) you have shocked it thermally. When this happens, the substance will constrict (similar to power lines in the winter) and lead to cracks and penetrations in the surface of the material. The first few pellets that hit a contaminant/substrate thermally shock it, causing the desired constriction, and the subsequent pellets fill those cracks and penetrations, and sublimate upon impact, literally blowing the contaminant from the substrate.
Let’s contrast that with the type of blasting that everyone has heard of, which is sandblasting. Sandblasting uses impact and friction to remove surface coatings and contaminants. Think of sandblasting like using thousands of tiny hammer and chisels. As you can imagine, the potential for damage increases exponentially when utilizing this type of force. I am all for sandblasting when it is the right tool for the job, but when it comes to industrial cleaning, nothing beats dry ice!
If you'd like to see some dry ice blasting in action, check out this video of us blasting cocoa powder.
