Quote:
Originally Posted by Brent Deines
I will add one more comment about 5 minute repairs. It only takes a few seconds to cure a think layer of resin on the surface of glass with a high quality UV light, or even in the sunlight for that matter. However, almost all glass used in windshields today is UV resistant. I don't remember how much UV it blocks right off the top of my head, but we have tested it ourselves and have verified this fact with several windshield manufacturers, and it is significant.
We don't know what kind of light technicians will be using when they cure a repair, so to be safe we recommend 5 minutes, and that is if you are not curing under pressure. If you are curing under pressure, the UV light directly over the pit area is considerably less, regardless of what type of lamp you use, so you should allow even more time.
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Brent;
I did some testing also, and my question is;
Did you test U.V. penetration of the glass or U.V. pentetration of the P.V.B.?
What U.V.wave lenght did you use? A or B or other?
When I repeatedly bonded 2 small test samples of glass without any P.V.B. present (I scraped and cleaned the P.V.B from the autoglass first before I also repeatedly tested it on plain flat glass samples) they cured in short order all the way thru.The glass broke before the bond would break. Even when I cured using the most mild U.V. sources.
My question is how you came to the conclusion that (quote) the glass used in windshields today is U.V. resistant with significance (Unquote).
I have found that the glass itself has no significant resistance to filtering for U.V. curing using both U.V. initiated chemicals or U.V. light meters,however, I have found that the P.V.B on the other hand did in fact filter out significant U.V rays.
To conclude, the U.V. does not go thru P.V.B when curing chemical in breaks in autoglass on the outside, hence,finding no significant increase in curing times from whats under the plastic or in the break.
I have found this to be nearly the same when testing many different chemicals on the market