New to the business

[shine masters]

Just added windshield repair into our auto detaling business. used a practice WS and find that the repairs show up cloudy. is this normal? Also wondering about the suction cup used for crack repairs. do I get these from delta kits or just the local hardware store?

[Brent Deines]

Cloudy is definitely not normal, and is typically a sign of moisture or other contamination in the break. Are you talking about the pit area or the entire break? Please give us more details.

Are you using Delta Kits equipment and methods? If so, you do not need a suction cup for crack repairs. Again, more details would be very helpful.

[shine masters]

Just the chip itself is cloudy. thanks! This is improving as i started using rubbing alchol and and air compressor to dry the area first. As for crack repair I am looking into suction cups vs crack spreaders. Which is better? And yes I am using the equipment provided through Delta Kits only.

[Brent Deines]

I'm glad to hear your repairs are coming out better. Other members of the windshield repair forum recommend using alcohol to dry out a chip, but I do not because if it comes in contact with the laminate it will melt it. Alcohol has a very low viscosity and will wick into the break very quickly. Also, rubbing alcohol has a higher water content than denatured alcohol. If you use an air compressor be sure you have a good filter to keep moisture and oil out of the line or you will do more harm than good. I use heat only for removing moisture.

I'm still confused by the whole suction cup for long crack thing. How would a suction cup be used in long crack repair? I occasionally use a crack spreader, but frankly don't find them necessary most of the time.

[GLASSTIME]

I agree with you brent. However I will be purchasing a delta crack expander so that I can have them in my arsenal of toys. For those just in case moments. I thus far can app enough pressure using my scribe or just a finger and this does the trick and of course my evaporator.
What I've found interesting is how the crack seems to vanish when I apply the inital 20 seconds of heat. When it cools it seems to appear faintly but not as strongly as before the heat was applied. This does work and infact the crack is a ghost when complete. Might I add each repair I've done thus far
Gives me a sense of esteem.

[screenman]

If you are talking about the repair looking smaller during your dryout process you are not letting it cool enough.

[SAFEWINDOW]

Just a little input on the whole alcohol thing; Brent is very right about rubbing alcohol, it has a high water content. Denatured is better for drying, but beware it also leaves a residue that you will not be able to clean out. although I have little WSR experience, I do however have 29yrs in the glass industry. if I had a way, I would force an alcohol, or other solvent vapor into the break and then vacuum out, thus displacing moisture and oils without leaving a residue that could interfere with resin bonding. Try pouring alcohol on glass, wipe off once, let the rest dry and you'll see and feel the oily residue.
On the alcohol melting the laminate (pvb) on contact, can't, and won't happen. It will slightly soften it "if"', you could put in mass amounts, and "if" you leave it too long. It would only melt if you were to light it, which you couldn't on a WS. Try this on a practice WS or flat lami and see for yourself. When cutting laminated, we would use generous amounts of denatured (lit) to soften the pvb enough to separate it so a blade can be inserted to cut it without chipping the edges. sometime we would have to burn it twice, and yes I have cut down WS's too. You should know the limitations of laminated glass. That goes for probing it as well. Make it melt, make it break, overheat it, twist it, stress it. Knowing your boundries with glass saves your rep, increases your confidence and saves on band-aids.

[Brent Deines]

Sorry Safewindow, but "slightly soften" is the understatement of the year. The alcohol will effectively melt the PVB. I have cut a lot of laminated glass in my career and was taught to score one side of the glass, snap, score the other side, snap, fill the crack with alcohol, and light on fire to melt the lam, but on a number of occasions, particularly when cutting large lites of glass, the glass separated on the score line before I had a chance to light it. Lighting it is the quick way for sure, but it is not necessary. I'm used to repair only guys challenging me on this, but so far you are the first person I have ever met with experience cutting lam that did not know what alcohol does to PVB. I have proved this over and over in our shop to people who did not believe me, but I guess I will have to shoot a video to post here so we don't have to keep bringing up the same tired old argument over and over again.

Actually melt is probably not the correct term here as that melting generally refers to heat. Perhaps softening, or dissolving is the better term, but the point is still the same. Alcohol will destroy the PVB.

Still don't believe me? Check out the book Organic Additives and Ceramic Processing, Second Edition by Daniel J. Shanefield, Page 175. http://books.google.com/books?id=UPwAys ... #PPA175,M1

[SAFEWINDOW]

As I don't want to create a fuss, we can agree to disagree.
The facts I have been witness to:
1. I have only seen one type of pvb separate on its own. It was specially designed for use in sound proofing type windows
2. The amount of alcohol you would normally introduce into a break would evaporate long before it truly "melts" the pvb.
3. Would it cause some damage to the pvb? Absolutely. It could and would cause the pvb to become "cloudy".
4. Does it leave a residue? Yes
5. Wanna see instant melt / delam, try MEK.

My original point was to stay away if possible from using alcohol. More from the residue issue than the melting issue.

Just for giggles i'll take a chunk of .090 pvb I have and put it in a jar of denatured and watch / take pics. I hope to prove myself wrong and ante up the humble pie. When I'm done with that i'll be thirsty...i'll have couple of drinks and melt my liver a little!

[screenman]

Scientific research may just prove that adding alchohol of any type may not help the moisture come out, I have read tests that show that the 2 seperate under temperature and that the alcohol comes out first, leaving the moisture behind on its own.

Having said that these are not my tests, I prefer nowadays not to introdue anything to the damage, however I did for 10 years use acetone.