UV shielding flat (vertical) glass on trucks

[glassdoctor]

Actually I specificly mentioned pit resin because it cures faster so it will be easier/quicker to get the "test results". Also, resin takes much longer to cure when it's NOT under a tab or inside a break.

For example, if you smear regular chip resin on a w/s in full sunlight it can take a long time to cure. But at the same time the same resin will cure very quickly inside the chip. Also, have you ever noticed that if there is excess resin next to a cure tab, it can still be liquid while the resin under tab is hardened?

So, if you do a test using chip resin, especially a full "vial" it will take many times longer to get a cure reaction than it would for the resin in the chip you are working on, if you get what I am trying say.

And the only issue that matters is whether or not the w/s blocks UV... the rear and side glass don't matter IF the w/s does.

BTW, don't ruin a whole bottle of resin for a test

[StarQuest]

Glassdoctor,

I think I understand what your saying. Correct me if I'm wrong though. Are you saying that even though the UV is hitting the inside of the windshield from the back or side glass it's still being filtered through the laminated layer? If that holds true, I guess the best way to test that theory is put my UV lamp on the inside of the shield and see what happens. Would you agree? I will try your method of testing out in the field though, it makes sense. That is if we ever get a sunny day here in Detroit again

Thanks for your help buddy

[glassdoctor]

Yeah... stick the UV light on the inside and see if it cures... that's all you need to know. That's an easy way to do test it.

My guess is that IF UV can penetrate the w/s and cure form the inside, it will take ten times longer than normal...

I have left resin onthe inside of the w/s before in bright sunlight and it didn't cure at all in the hour or so I left it there.

[maxryde]

Hey guys I have cured from the inside of the glass under pressure and have the ruined seal to attest to this, as far as length of time curring I didn't use a stopwatch but I don't think it was very long over the usual 5 or so minutes. When I work with alot of sun (this dosen't happen much here in the Northwest) I shield repairs in the direction the light is coming from. While I cannot be sure of sunlight being an issue after passing thru a side or back window and then the inner layer to the affected area.(I.E. uv intensity, refraction, etc.....) I don't need to worry about all the outside issues if I just block the light out and it just takes a second to put a shield of one kind or another, (towel or whatever) If I am wrong about this issue I would appreciate being corrected. Hey what about uv's bending as they pass thru glass just like they do in water is that an issue? Scott

[glassdoctor]

maxryde, when you cured form the inside, did you have the injector covered with a rag, etc? Even many overcast days have enough UV to cure resin...

I have heard this before, but I wonder if the actual curing came from outside, and not the light stuck on the inside of the glass.

My experience has always been that resin won't cure this way.

[maxryde]

Good question glassdoctor I don't remember covering the repair but I do work in the shade as much as possible. I seem to remember a post about curing from the inside under pressure for a repair that didn't want to stay filled following the removal of the injector or something like that. My memory isn't the best I've got a mind like a steel trap, better keep your fingers back!! Scott

[glassdoctor]

I know what you mean... I have forgotten more than I know, and I'm not that old. :-k