Abrasives are absolutely critical to cleaning windows. Few manufacturers have made a study of them however. I have written several articles on the technology of abrasive particles. Take a look at this one web site. http://abrasive-media.com/article.php?pid=25&cid=28 This company obviously is in China where Perry lives. Their focus is on iron sand abrasives used in blasting. If you read about the attention paid to the properties of the particles you will see how such controls the performance.
There is a great deal of difference in the purity of size, hardness, friability, shape, functionality, and chemistry of micro and nano particles. All of these properties control how well they "cut" through the surface, how smooth that new surface will be, whether there are particles that stick together forming much larger particles (agglomerates) that will leave errant scratches, how efficient the slurry will be, and so many other properties.
But why are they important for window cleaning? Well have you ever used a magic sponge from Mr. Clean? If so you were working with an abrasive impregnated sponge. Have you ever worked with a plastic scrub pad from 3M? This is a type of plastic abrasive. Most likely nylon. Possibly impregnated with silica particles. We will never know exactly what because 3M doesn't tell anyone anything. What of steel wool? Most of us use 0000 steel wool. This is an abrasive. Each extremely fine strand of wool is only 20 microns in diameter. Further it has a peculiar shape which allows it to do its work. According to this video they are razor sharp and have a triangular shape. It is my guess that they leave very few if any scratches at 0000 because wool is not based on a particle but rather a strand. So rather than cut it rubs. Kind of like really small razor blades. The problem we have is that they rust so quickly. Leaving a red stain on white vinyl frames or paint.
If you look into compositional abrasives you will find some fascinating animals out there. Such as plastic abrasives. These are softer than glass, but are rather sharp. So they cut through stuff like cured silicone caulk, paint, and wood stain. Add a solvent like DLimonene at 90% purity and you have an effective tool. It also won't rust. The problem that I have with acrylic particles for example, is they are only sold down to 177 microns. Maybe 100 microns. But I want them down to 20 or even 15 microns. That would be equal to around 600 to 700 mesh.
Regarding compositionals there are also some very hard woods like walnut shell. These are much better for the ecology. The only problem is they do tend to absorb water and can become soft. They also are difficult to get as a very fine micronized powder. Nonetheless I do see them as a possible creative solution to various problems.
Here is another fascinating abrasive idea. Actually using frozen carbon dioxide particles as a blast medium for cleaning various surfaces. I wonder how it might work on glass. http://www.coldjet.com/
One thing I am working on now is removing hard water spots from glass sealants. I first want a hydrophylic silane sealant that can be applied to the glass once it has been polished. The sealant should be water miscible so it will go on quickly with our cleaner. Soap, squeegee and you're done. This sealant should also stand up to high pH water runoff from concrete or groundwater. Then the applicator used to clean must also remove any newly formed hard water spots using some type of abrasive. That abrasive coupled with the new surface treated with a sealant should release the new spots. Further the cleaning solution will put down a new silane treatment for the next cleaning.
This is not just an idea. I have already had success with screen stain (which is an aluminum dioxide deposit), Rain X, and 0000 steel wool. All I need to do is change the players for concrete efflorescence and sprinkler system spots. The abrasive should not be one that will remove glass. It must not be that aggressive. Rather it should be aggressive enough to remove the new spots from the silane coating. Hopefully it also will not remove much if any of the silane. But the solution that is used to scrub with (clean) will also put down another coat of silane.
Written by Henry Grover Jr.
henrygroverjr@gmail.com
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1 comment:
Hey this was a really informative post for me.So thank you for sharing it with us and I learnt a lot.I am sure that others will find this a good post as well. Keep it up.
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