Thursday, July 13, 2006

Glass Destruction Via Weld Splatter

Simply put the temperature of the sparks that come from weld or even metal cutting wheels, are quite hot. Hot enough to melt glass surfaces. There has been a great deal of damage done by people all over the world working on metal close to glass windows and glass railings. Usually they think these are just little black or brown spots that the window cleaner can just "pop off"! But not. If you take a single edged razor blade and place the pointed tip into the "spot";... you will immediately learn the truth. That "spot" is actually a little hole with some metal residue where the spark melted its way right into the glass surface. Your blade tip will sink in and not move. This type of damage can not be easily fixed. Almost all of the time it is impossible. Since sparks fly, and there are a lot of them, the entire surface area is usually damaged. I suppose if there were just a few or several holes that weren't that deep they might be able to be polished away. But this is just a dream. Anyone working close to glass with metal cutting or welding equipment should take every precaution by protecting the glass. Otherwise irrepairable damage will happen. Which could easily cost tens of thousands of dollars in glass replacement. This won't make anyone happy. This information is brought to you by your S.M.A.R.T. Window Cleaner.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Monday, June 26, 2006

Finding a S.M.A.R.T. Window Cleaner

If you are looking for a "Professional Window Cleaner", don't pick the first company that swings a squeegee and advertises in the local paper. If you do you might end up with scratched or etched window glass. They need to be glass cleaning surface techs. This means they must not only be able to clean a window without leaving streaks. But also should be able to identify what type of surface they are working on; whether there is fabrication debris embedded in the tempered glass; has someone damaged the surface before them; and what restoration products/chems are safe for the window (will not chemically attack/etch, or scratch). Regarding the issue of fabrication debris. I have written an entire post in this blog on the subject. It has become a problem, as tempered glass is being turned out with surfaces that cannot be scraped or else the microfines will scratch the glass. Not the razor. So how does one deal with such a problem? Further, windows are much more advanced then they were just a few years ago. So they are much more costly. Companys have created all types of Low E coatings which have been applied to those surfaces we come into contact with, and those we cannot touch. These are called Super Windows. But there are Smart Windows too. Such as electrochromics and suspended particle device. Some of these windows can easily cost over fifty bux per square foot to replace. Currently companys are working on ways to make windows photovoltaic. This means instead of simply being solar filters, they are being converted to sun powered electrical generators. Also, have you ever heard of Self Cleaning glass? This is a titanium dioxide coating which is photocatalytic ( powered by UV radiation), and hydrophilic (water loving). It is supposed to break down dirt with the energy of the sun, then rinse it away with the rain. How does one clean/maintain such a surface? Also, if it gets covered with different types of post construction debris like paint overspray;... how does one remove this without doing harm to this new high tech surface? So we can see that windows do in fact require window cleaners to be Surface Maintenance And Restoration Technicians. We need to be S.M.A.R.T.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Saturday, June 24, 2006

The Destructive Power of HF

Hydrofluoric acid (HF) eats up most hard water spots based on a silicon chemistry with a voracious appetite. It is for this reason that commercial products based on HF have been created for clearing window glass damaged by ground water in sprinklers, and concrete efflorescence. Each can leave behind extreme mineral deposits based on a spiked silicon fingerprint. At times it might even appear that no damage has been done to the glass during the "restoration" process using HF. However looks can be decieving. The simple facts are that whenever an HF solution of as low as one percent makes contact with glass for as little time as thirty seconds, a chemical reaction takes place. From my own observations alone I would venture to say this is a stage two dynamic etch. That means that the silicate/silica matrix of the glass has been dissolved and dynamically removed, leaving behind a new surface. Which surface is much more rough on a microscopic level than that of brand new glass. But you won't need a microscope to prove this. Just lightly run your finger across this new dry surface. The surface will also cause pure water to sheet out very well without leaving hardly any drops.
Here are a couple of experiments you can do yourself in your own kitchen to prove to yourself what I have said is true. Take a small three by three inch slide of window glass, and dip it in a cup of HF at only one to two percent concentration. Only emmerse one half of it. Leave it there for a minute. Remove it, rinse it, and dry it completely. You will notice the "water line". This is a line showing where a stage two dynamic etch happened. Next take a six by six inch mirror square. Create a good four by four inch patch of scratches in the center. Now apply only a one to two percent solution of HF to one half of your scratch patch for thirty to sixty seconds. Rinse quickly, and dry. You will see that the scratches which made contact with the HF solution have been severely magnified. Another interesting test involves drawing a letter on a mirror plate using a paint marker from Faber Castell. Once drawn rub a dilute solution of HF over the entire area untill the paint has been removed. Now rinse and dry. You will be able to see where the paint was. There will be a clear distortion of the glass only where the paint was. So you will still be able to make out which letter you had drawn. I remember visiting a building once where some HF had been used to remove long drip lines of a concrete silicone sealant from some dark glass. The sealant was gone, but there were long band lines left as a clear distortion of the glass. Further there was a clear orange peal effect showing where the hard water spots were. If you drive down the highway and check out some of the older glass boxes that have had HF used on them for many years, you will be able to see this type of distortion. Any type of waviness on glass plates is much easier to see from a distance. Now in the case of scratches. How do you know that someone has not been there before you and removed the previous spots with a crude abrasive? You will remove the second batch of spots, but in so doing you will also severely magnify the scratches leftover from the first time. Not good. Since the owner (who never seen the scratches before) will now think that you caused them to begin with. I can go on. But hopefully this info should help anyone who reads this, to understand why I would never suggest that anyone use HF on windows, unless they are plexiglass. Then there are other dangers to contend with too. It is not a forgiving chemical. Further;...if you do any experiments with it always use adequate precautions. Gloves, eye protection, etc. Since there are some serious health risks involved too. My advice is always to stay on the side of caution. I hope no one misunderstands me. My intent has never been to do anyone harm. Also, ultimately it will be the Window Cleaner that has to make a decision as to what they will use to remove anything from the window. It is your company and you are the commanding chief.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Sunday, June 18, 2006

Hard Water Spot Removal Techniques

Hard water spots come from hard water drops when they evaporate. Hard water comes from the ground (sprinkers or the garden hose), and concrete/brick efflorescence. It is called "hard" because of the total dissolved solids (TDS). The key word being solids. Basically these solids are microscopic pieces of rock or minerals. So another name for hard water spots is mineral deposits. When the water poofs away in the hot sun, these little pieces of rock are left behind. Most of the time they are based on a silicate chemistry. This is a silicon molecule that includes the elements oxygen and some metal (calcium, sodium, magnesium, etc.). Window glass is based on a silica/silicate matrix. Silica is silicon and oxygen only. Most of the silicates in glass are based on calcium and sodium. Since the chemistry of most hard water spots is very similar to that of window glass, they usually form a good bond. Another reason they bond well is size. These little pieces of rock are around two to five microns across most of the time. Also the microscopic pores of window glass are about five microns. So these mineral particles "fit" very well into the micropores of glass surfaces. And there they stick! As we know all too well.
Most if not all of the hard water spot removal products on the commercial market are based on acids and or abrasives. The idea is to either chemically eat up these little pieces of rock, or abrade them away physically;...or both at the same time. I've always been in favor of the very last option. If the spots are based mostly on a silicate chemistry, then the only acids that will eat them up are those that will eat up the surface of the window glass. Here I am talking about mineral acids. So called because they are not based on a carbon chemistry like glyconic acid. Some common mineral acids that work good at dissolving mineral deposits based on silicates, and etching glass surfaces;... are hydrofluoric, sulfuric, and ammoniumbifluoride. If the spots are based almost entirely on calcium carbonate or sodium carbonate;... mild acids like sulfamic, acetic, citric, or glycolic will work well. Then if you add a polishing powder such as an optical grade silica, cerium oxide, or aluminum oxide;...you will have the best of both worlds for a real quick fix. I never advise the use of mineral acids which are glass etchants. If the spots are based almost entirely on silicates, then the only way to deal with them effectively and safely is by means of a refined optical grade polishing compound or slurry. Any milder organic acids at this point are a simple waste of time and money. A few quick tests will determine in a matter of minutes exactly what the nature of the problem is.
Now while there are many different hard water spot removal products out there on the commercial market, I strongly urge extreme caution. Many of the manufacturers of these products have little knowledge of the technical nature of the problem;... along with the products and techniques necessary to safely and effectively solve it. Education is critical. Anyone performing glass restoration needs to be completely educated. Otherwise they could waste entire buildings, and bring on themselves tremendous lawsuits. I have been called in to consult on several such. This kind of education is one of the reasons I have established this blog. There will be more articles on hard water spot removal techniques posted here in coming days.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Sunday, May 28, 2006

Micronized Cleaning Dispersions

Synthetic detergents along with certain cleaners such as ammonia can only do so much in removing contaminants such as greasy finger prints. By adding certain silica particles to your cleaning solution it becomes possible to "scour" the microscopic surface of glass without doing harm to it. All that is needed is a handfull of powder to about three gallons of soapy water. Even a mild soap can be used. Here the soap such as a cationic surfactant is used primarily to add glide to your squeegee blade. Not so much to clean. The silica particles which are about the same size as the diameter of the pores of a glass surface will do most of the cleaning. They will effectively scour the surface. Reaching deep down into the pores, digging out any and all grease or any other contaminant. The zeta potential isn't great enough to keep these particles permanantly suspended. We would have to drop down to the nano level for that. But they will stay suspended for a few hours while you work with your cleaner. When working you will notice that the color of the water will turn a slight white. But this is good since it lets you know that your particles are in suspension where they will be most effective. When you dump out your bucket there will be some powder left at the bottom. But not much. This however is the reason why no one has commercialized a product like this. Although it might be possible to add the powder directly to the pure syn-det. There it likely will remain in suspension much longer. A time limit of six months is required for all commercial products. This is called the shelf life. Particles are also chemically treated to help bring them into a water based suspension. In fact, if they have not been properly treated, they will not go into suspension at all.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Thursday, May 25, 2006

GTC DVD Tutorials

I will begin production of a line of DVD Tutorials in July. I have contracted with a company experienced in video productions to create a specialty line of teaching aids to help certain ones in the Window Cleaning Industry understand and best perform glass surface restoration. The first one entitled "understanding glass stains" will be free. It has always been my goal for the last fifteen years to write and create other teaching aids. To learn and create custom products for solving problems and expanding our current means of earning a living. I want to give back to the industry just some of what it has given to me. There might be times when the formulations that I develop will be too involved. Also they will have shelf lifes of one day to only a week. In this case it will be necessary to establish a network of short order toll mixers around the world to help us out. Or at the very least to train individuals in different companys by means of DVD exactly how to put together such formulations. I know this sounds complicated and intense, but I do believe that the window cleaning industry will continue to rise and learn. Also there will be chosen companys that will take advantage of such custom products. These are the ones that will take the lead in the technology of window glass cleaning, restoration, and preservation! I am certainly not the only one dedicated to this. There are others within our ranks who are working hard. Forming new associations, building machines, creating teaching aids, setting up web sites, and on and on. These ones we all know by first name. I have nothing but good things to say about them. And I am sure they will help me on my journey too.

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com

Monday, May 22, 2006

Artificial Hard Water Spots

Hard water spots are otherwise called mineral deposits. They are based on various metal salts. Also silicates. It is the silicates which are the most difficult to remove. These are based on a silicon chemistry, and will bond exceptionally well to a glass surface. Usually the only acids that will dissolve silicate deposits are those that chemically attack the glass surface itself. Here we are talking about acids such as hydrofluoric, sulfuric, and ammoniumbifluoride. Many of the hard water spotting problems out there are due to silicates. These come from ground water, and from concrete efflorescence (or leaching). The micropores in the surface of concrete building facades soak up rain water (which is acidic). There the rain reacts with the minerals in the concrete bringing them into dissolution. The now mineral laden rain water leaches out of the micropores, down over the glass. When the sun comes out the drops evaporate, leaving behind the minerals that were formed when the rain reacted with the concrete. These silicates are usually very high in silicon. I remember seeing an elemental read out one time of the various elements present in a sample that was scraped off a window. The silicon spiked off the page. The reason I am going over this information is to show what type of stains are chemically much more likely to really stick to the glass. This is the type of stain that we would like to duplicate on a microlapped surface in order to test various glass protectants to see which one works best at keeping the spots from locking on. Simply put;...silicates. Now if one takes what is called water glass (sodium metasilicate), and mixes only several tablespoons in a quart of water, it is possible to create your own silicate deposits. All you have to do is microlap a window that gets direct sun, then sprinkle your formula on the glass. Spots will form when the water drops evaporate. At times they will stick instantly. Or some time in the hot sun might be needed. Either way, you have created what I arbitrarily call "artificial hard water spots".

Henry Grover Jr.
Glass Tech Consulting
gtcnews@hotmail.com