Curing under pressure.

[splitpit]

Yes, curing under pressure would still leave the pit damp with resin to add pit resin into for the final cure. My point was and once again correct me if I'm wrong, the ideal situation in terms of getting the best bond of resin in the pit is for the windshield repair resin and the pit resin to interact with each other while still in a wet state and THEN cure!

[screenman]

It may be the way my English comes across as I am from the UK I am not very good at it. This may come as a major shock Splitpit but I was agreeing with you all the way. Now watch some bloke cleverer than us come and tell us we are both wrong.

[harrellbenjamin]

Originally Posted by screenman

It may be the way my English comes across as I am from the UK I am not very good at it. This may come as a major shock Splitpit but I was agreeing with you all the way. Now watch some bloke cleverer than us come and tell us we are both wrong.

No chance of that LOL Splitpit is never wrong.....just ask him lol

[splitpit]

There's your clever bloke!

[jayjacque]

Screenman, those 2 examples: cracks or legs that are open to the surface and extra big hits especially on more vertical windshields where resin could pour out, those are 2 pretty good examples for CUP. That's why I love this forum!

And Splitpit, I think I agree with you in theory anyway. That's why I normally don't let the resin cure all the way before slipping in the pit resin; half way or probably more like just 20 or 30 seconds. Come to think of it, it wasn't entirely self-taught. A Novus guy showed me that back in early 90's. Sorry it sounds like I keep changing my story. What can I say, I'm getting older and forgetful. LOL

[splitpit]

I know that Novus doesn't promote that practice so he must have been self taught as well. Any curing of the windshield repair repair resin in the pit prior to filling and curing with pit resin would inhibit the combined chemical interlock of the resins.

[Brent Deines]

I can't say that we have actually tested for the interlock properties of wet on wet vs wet on cured resin. I am strongly opposed to curing under pressure, but it has nothing to do with the interlock properties, however, I would guess, and it's only a guess, that you it is quite possible that wet on wet provides a better bond.

The reason I am against curing under pressure is that when the injector is applied to the glass, the pressure required to create a good seal often partially closes the cracks. So when you fill the cracks with resin the only way to know for sure if you got them completely filled is to remove the injector.

I have played with dozens of different systems over the years, and found that with many a star break will look good until I remove the injector, but when the injector is removed I will see some air in the cracks, or sometimes in the pit area. Less pressure is necessary to seal the injector against the glass when using a vacuum cup to the injector to the glass, so the problem is less prevalent than when using a system that uses one or more suction cups to mount the injector to the glass, but it can happen with any system. Therefore, I feel it is very important to swivel the injector away from the repair if the system allows, or remove the injector completely if necessary to inspect the repair prior to curing.

What this does is allow the windshield to return to it's original state prior to curing. Not only does this allow the technician to make sure all the air is out of the break, but it also removes the stress that is placed on the glass from the pressure of the injector. I believe some systems are incapable of getting all the air out of the break, so they must cure under pressure, but I feel this is cheating, and does not provide the best possible results.

Repairs can also be completed faster if they are not cured under pressure as there is the curing light is applied directly over the break, and the second curing step is eliminated. If the interlock properties are better as well, that is just one more reason not to cure under pressure.

[splitpit]

Thank you for your input Brent. When you have a chance, ask a Delta chemist about the issue of chemical interlock, wet vs dry. I'd like to hear what they say.