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Windshield Scatches


rcirilli
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Sorry Bob, I do not know of any cure for that sort of scratch. If you can catch your nail on it, then it's beyond repairing. Buffing any scratch or groove that deep will only distort the glass. I feel certain Howard will back me on this unless he's found or heard of a miracle cure since the last time we talked about this.<P>Rick

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Rick ~ You are absolutely correct so far as I know. If I knew how to do it, I would have done that with my '55 Buick, rather than buy a new windshield, which I was lucky to find.<P>When you remove a scratch that you can feel with a fingernail, you must necessarily remove enough glass to bring the surrounding area DOWN to the same level. You have effectively created a lens in that spot which distorts the vision through that area.<P>You can also "burn" tha glass if you build up too much heat in the buffing process. It will then look like you are looking through water.<P>The best you can hope to do is shine up the "white rubs" a little with jewelers rouge or a product called cerium oxide.<P>Frankly, you will just be wasting your time if you hope to really fix it.<P>I have been out of the glass business for a number of years now, and there may be some new "miracle cure" out there I have never heard of. However if Rick has not heard of it, I doubt it exists. I think that is like the 100 mile per gallon carb. There ain't none.<P>hvs

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While I tend to agree that this cant be done, I wonder if the stuff they fill "Starbursts" from rocks might not work to fill the scratches. <BR>I have never had to use that process on any of my daily drivers but hear it works well.<BR>Just an idea to look at.<BR>Bill

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Bill ~ I don't think so. I believe that part of the star repair is that the product in forced down into the crack to the layer of vinyl acetate binder and probably seals from the inside out. In this case we are dealing with surface scratches and there is no crack to seal. Therefore the material would lay on the surface of the W/S and into a shallow grove and I cannot see how it would do any good.<P>But if there is a chance it would work why not ask one of those star repair guys if it can be done. But don't pay until it is successful.<P>I cannot help but believe that after all these years of star repair technology someone has not tried deep scratch repair. It would be a gold mine. So far, no one is advertising that kind of repair service. <P>hvs smile.gif" border="0smile.gif" border="0

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Thanks for the feed back, it's as I suspected. HVS, that was a good explaination that is easily understood when you look at it from the right prespective. <P>I've used the fill a crack and agree it would be a wat of time and money.

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Thanks Howard for the lesson in glass. I was wondering how that stuff worked an now I know.<BR>One more glass question for you, If the film between is yellow and cracked, is there anything you can do ? Some of my glass on the Buick is in poor shape and I think I am going to have to replace it at some point.<BR>Thanks<BR>Bill

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Bill ~ Early laminated safety glass used a form of rather hard plastic like lucite as the interlayer. It was so hard that it could not be cut as modern laminated glass is by first cutting both pieces of glass and then the binder with a razor blade. It had to be softened on an electric heating wire before it could be cut. Then the cut edge was filled with some sort of black sealer to prevent separation from the edges in. You might have some of that in some of the windows on your Buick.<P>AOL just called--I'll be back. Boy did AOL just do a number on me. Thought they had melted my modem. rolleyes.gif" border="0 <P>Back to our story. smile.gif" border="0 When the safety glass was manufactured for the car manufacturer the two pieces of glass were first cut to pattern and then laminated, so the seal was pretty good. In the replacement market the glass was cut to pattern from "block sizes' of stock glass say 18x28 and then the binder was melted. This left somewhat of a more open edge and more subject to moisture penetration leading to discoloration and separation.<P>When the glsss discolors it indicates that the glass has separated, or partially separated from the binder. Thus it is no longer really safety glass because if struck it will fly into pieces because it is free from the binder. <B>REPLACE IT!</B>. shocked.gif" border="0 <P>Modern laminated safety glass has a vinyl acetate binder which is soft and pliable and adheres to the glass much better.<P>I hope this answers the safety glass question. smile.gif" border="0 <P>hvs<p>[ 04-30-2001: Message edited by: hvs ]

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Howard, I replaced the windshield glass on my '77 Kenworth a few back because it was clouding. The glass was original and I figured at the time it's close to 20 years old and finally separating. Within 2 years the new glass was starting to cloud. They're flat pieces, which shouldn't make a difference I would think, but what would cause them to cloud so soon? Do they just take too much of a beating or should the gasket have been replaced as well? The glass man, at the time, said they were fine and didn't need changed. He's now out of business so I can't go back to him. Have any ideas? confused.gif" border="0

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Beats the heck out of me Al. I have never heard of modern laminated glass doing that. I have never seen a piece of post WW II laminated glass separate or cloud up internally. On a '77? Can't understand it.<BR>If you replace this one, save the old one. I would like to see it and try to figure out <B>WHY</B>. <P>Is there a manufacturer's logo anywhere on the replacement W/S. By law it must be there, but some shops when using old odds and ends of glass they have around lose the logo. They are particularly casual when it comes to work truck replacements. If no logo, is there one on any of the other original glass. If you find one on the W/S or anywhere, tell me what it is.<P>Bill S ~ I have been thinking what the binder was on the old laminated glass and I think it may have been celluloid or something like that rather than lucite.<BR>Memory fades with age. confused.gif" border="0 <P>hvs

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Howard,<P>Reading Al's posting here, I recall a piece of flat that I had cut not long ago for the one car here in the shop. After getting the glass back here, I un-wrapped all 6 pieces at once. I noticed the one had, what looked like tiny air pockets about a 1/16" to a 1/8th" in on the inside the one edge. I didn't use it as I just felt certain it would grow out in time. My glass shop cut me a new piece at no charge and no questions asked. Would this have been from the cutting and wet belting of the edges to fast or to hard, or just a bad section of glass? My glass mans answer to that was, it just happens sometimes. rolleyes.gif" border="0 <P>Rick<p>[ 05-01-2001: Message edited by: Rick Hoover ]

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Rick ~ Your glassman was right . It does happen sometines, but it happens for a reason. Based on my experience, the edge bubbles usually occur when the glass is cold when cut, and so when you bend the glass at the cut to get to the vinyl acetate to cut it with the razorblade, you pull and stretch the binder. Then after the cut, when the vinyl shrinks and pulls back, the air bubbles came with it. When the edge is covered by a channel you don't see the bubbles and it takes years for them to possibly move a little further into the glass. Most glass shops don't worry about the edges other than the ones that are exposed and poilished. <P><BR><B>DISCLAIMER!!</B> smile.gif" border="0 I was in the glass distribution business and never was in the auto glass installation business. I sold them their glass. Therefore my experience with the product was in a different area than your local glass shop. I knew what my customers did with the glass, but I never was an auto glass installer. I was, however, a glass cutter at the distribution level. For many years we had a small glass shop rentimg a part of our building and that is where I learned what I know about auto glass and its installation.<P>Now back to laminated safety glass. As a distributor we cut a lot of laminated glass cut to size for door manufacturers. That all went into wood sash and careful and perfect cutting was not necessary. However, I had a trick I used when I wanted to make a perfect cut with no chips or vinyl pull, like cutting glass for my own or friends cars.<P>Cut both sides of the glass and make sure that one cut is perfectly on top of the other. Using a hand held pump oiler squirt denatured alcohol on the cut. Light it. Then ever so gently bend the glass along the cut. It will begin to open up and the heat and alcohol will work into the opening and both melt and dissolve the binder. A gentle pass with a razor blade will complete a perfect cut. No chips, no binder pull and no bubbles.<P>Lets not let this thing go much further because you are reaching the limits of my knowledge. wink.gif" border="0 <P>Howard smile.gif" border="0smile.gif" border="0<p>[ 05-01-2001: Message edited by: hvs ]

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Thanks for taking the time to explain that Howard. Now, we all know just about enough of the glass business to make us dangerous!<P>We will let you rest now, as you have earned your DF Tech Advisors salary for the week.<BR>And to think, it's only Tuesday! grin.gif" border="0

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I just have to ask.. <P>1.My 54 Chev windshield has small pits, seems like it was in a sand storm, can those be removed?<P>2. Some earlier owners attempt at sanding for a paint job did not end at the body, but included some of the glass, what do I buff those out with?<P>Many thanks. : smile.gif" border="0

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Answer to #1 - You can't. frown.gif" border="0<P>Answer to #2 - If you can feel the scratches with your fingernail, you can't buff them out. frown.gif" border="0<P>In both cases polishing will ruin the windshield by creating distortion. shocked.gif" border="0<P>hvs<P>A further thought. On a 54 model all the glass except the W/S and backlite are flat laminated safety glass. A good glass shop can replace these at a reasonable price. You would spend days polishing the sidelites and have a mess when finished.<P>If the W/S has only sand pits, live with them like most of us out here in Wyoming do with our modern cars. We have constant wind and sandy soil, as well as the fact that we do not use salt when it snows. Just sand and some crushed lava rock. New windshields are available at a price. I finally had to put one in my '55 Buick.<P>hv<p>[ 05-06-2001: Message edited by: hvs ]

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Howard, sorry it took me so long to respond, but a dirty four letter word(work) gets in the way of my fun. I copied down what the glass says and here it is:<P> GUARDMAN<BR> safetyfloat<BR> tint<BR> laminated<BR> AS-1-84 GG-M84<BR> DOT-22<BR> 5A<P>There's about an inch at the bottom of both windshields that is clouded. It goes the whole way across the bottom and is slightly up the sides. This is the same reason I replaced them originally, plus for the sand blasting they got driving the interstates. They're not that expensive, but it still ticks me off.

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Al ~ That most likely says "GUARDIAN". The Guardian Glass Company of Detroit, Mich. [at least that is where it was when I closed up shop 11 years ago] started over 50 years ago as a small manufacturer of flat laminated glass but over the years has grown in to a MAJOR glass manufacturer [all kinds]. They are OEM, supplying a number of car, truck and bus manufacturers.<P>I'm guessing that the "84" is a date of manufacture. Even so, it should not be separating as I have seen Guardian laminated glass remain completely intact and in a vehicle for over 45 years. We handled their products and in 1949 they gave us a pair of custom made tinted sunshade windshields for my father's'41 Cadillac. I removed them from the car 5 years ago for authenticity's sake and they showed no sigm of separation.<P>I guess what I am trying to say is that I cannot understand why the separation occurred, especially in both original and replacement units. confused.gif" border="0 ~ Howard

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