Windows delaminating prevention

[Buick35]

My old car sits covered in a non climate controlled garage when not being driven.Is it better to roll the windows down a little to help with them from delaminating or separating or anything else that would help short of air conditioning the garage?Thanks

[avgwarhawk]

Water and sunlight delaminate glass as I understand it.   The glass should be fine in your garage as it is. 

[Buick35]

Thanks,I'll try not to get them wet.

[MGRAB]

Years ago, I managed a plant that produced laminated safety glass.  It is unfortunately an irreversible process once the delamination starts.  A part of the process of making this glass involves utilizing an autoclave to achieve clarity and adhesion.  If there is some delamination or air bubbles you can re-autoclave the glass (usually) a second time, though results are usually not good.  Sometime an airbag is utilized (under vacuum) that can help draw air out during the process.  Over time interlayers become very brittle, this also happens when you repeat the autoclaving process.  With lami that is this old this would not be an option, in fact old lami can become dangerous if it gets too brittle.  For your windshield its objective is to prevent projectiles coming straight thru.  As it ages it loses its elasticity and ability to do this.  The right amount of adhesion is critical to maximize its safety.  Too much adhesion will hinder its ability to prevent a projectile to pass through.  It's actually optimal to slightly less adhesion.  This is accomplished sometimes by bonding to the air side of the glass and not the tin side (made on a molten bed of tin).  If you have a seriously delaminated piece of glass, replace.  This is called "safety glass" for a reason.  This is one of those things where originality isn't worth it, at least for me.

[Bryan G]

Another hobby of mine is collecting/tinkering with vintage televisions. Starting in the late 50s, some picture tubes used a bonded faceplate, just a form-fitted glass that was glued to the front. These have a bad habit of delaminating/discoloring, just like safety glass in cars. With heat, or extended water soak, the bonding agent can be softened enough to remove the glass. In those cases, hobbyists just reseal the edges, something not visible in those cases but you couldn't get away with it on a car. I've knocked around the idea of trying to separate a scrap piece of safety glass from an automobile; my thought is there would be no way to totally reseal it without bubbles forming unless you had the equipment that MGRAB mentions. 

[Paul Dobbin]

Is it a Old Wives Tale that sealing the edge of the glass will prevent the delamination?  If so, what to seal it with?

[Frank DuVal]

Hi Bryan, yep, it's called a cataract in the CRT world. I have several that need that done in the future. There seems to be no plastic layer, like in windshields, just a bond (glue) layer. One video shows a small room heater and a heat gun to raise the glass temperature and then a Slim-Jim is slipped between the layers to cut the glue. See, I brought it back to automotive discussion with the Slim-Jim tool mention.😁

[MGRAB]

12 hours ago, Paul Dobbin said:

Is it a Old Wives Tale that sealing the edge of the glass will prevent the delamination?  If so, what to seal it with?

I wouldn't call it that at all, in fact doing that could help.  All annealed laminated glass I've seen delaminate starts from the edge where it absorbs moisture from the atmosphere.  Tempered laminated can start from the center buts that's for different reasons and not used in automotive applications.  If I were to try this, I would purchase a resin that is used for chip and bullseye crack repairs.  You can get a few different viscosities and I would probably get the lowest, so it flows better.  This would be compatible with both glass and the PVB (Polyvinyl Butyral) interlayer.  One problem you will have is getting it to flow into a void as repair techs will use a special tool to put the cavity under vacuum and draw the liquid in, capillary action is not enough to fill a void.  You may have to use a razor knife to slightly open areas up.  This could have some merit to sealing the edge... never tried though.

 

Once it's delaminated it done though, PVB roll stock is very hydroscopic and it is stored in very dry, very cold conditions before use. Once moisture has gotten to it it's done.  No magic fix unfortunately, it's up there with your 80's faded, cracked dashboard for being salvageable.  Just to give you an idea of how moisture impacts its performance and longevity: We use to conduct the ASTM ball drop test for the types of panels we made.  I always knew that moisture (like bonding to the air side of glass) could make a more impact resistant panel.  For fun one day I wanted to see what spraying the interlayer with water prior to laying it up the cleanroom would do.  I actually got the 5 lb. drop ball to bounce off the panel, they always shatter the glass in normal conditions.  However, two weeks later out in the yard they started to delaminate already, a very short-lived unit.  

[SC38dls]

These are on my 38 Studebaker rear window and drivers door windows. Do you think they can be fixed?😳

dave s

 

ps- I did replace the windshield but wanted to keep the rest original. 

Edited February 26, 2023 by SC38dls (see edit history)

[Buick35]

Having new glass made isn't that expensive as long as it's flat.I had to do some on my Buick.Then I bought the "widow bug" stencils from Mark-n-gard.

[Paul Dobbin]

I've replaced all the glass i almost all the cars I restored.  The last few have received flat Tempered Glass. except the windshields, which got laminated glass.  Cost a little more but does not have the problems of delamination and cracks.   

[Leif in Calif]

12 hours ago, MGRAB said:

I wouldn't call it that at all, in fact doing that could help.  All annealed laminated glass I've seen delaminate starts from the edge where it absorbs moisture from the atmosphere.  Tempered laminated can start from the center buts that's for different reasons and not used in automotive applications.  If I were to try this, I would purchase a resin that is used for chip and bullseye crack repairs.  You can get a few different viscosities and I would probably get the lowest, so it flows better.  This would be compatible with both glass and the PVB (Polyvinyl Butyral) interlayer.  One problem you will have is getting it to flow into a void as repair techs will use a special tool to put the cavity under vacuum and draw the liquid in, capillary action is not enough to fill a void.  You may have to use a razor knife to slightly open areas up.  This could have some merit to sealing the edge... never tried though.

 

Once it's delaminated it done though, PVB roll stock is very hydroscopic and it is stored in very dry, very cold conditions before use. Once moisture has gotten to it it's done.  No magic fix unfortunately, it's up there with your 80's faded, cracked dashboard for being salvageable.  Just to give you an idea of how moisture impacts its performance and longevity: We use to conduct the ASTM ball drop test for the types of panels we made.  I always knew that moisture (like bonding to the air side of glass) could make a more impact resistant panel.  For fun one day I wanted to see what spraying the interlayer with water prior to laying it up the cleanroom would do.  I actually got the 5 lb. drop ball to bounce off the panel, they always shatter the glass in normal conditions.  However, two weeks later out in the yard they started to delaminate already, a very short-lived unit.  

Retired Pilkington / LOF guy here...you are 100% correct in all you say. 

[Frank DuVal]

Sure, Dave, they can be fixed easy, just a call to a local shop that cuts glass!👍

[SC38dls]

Thanks Frank, I am doing the wing window as the plastic center is beginning to curl and break. Until I can’t see out of the rear window or either of them break I will leave them original. I’m hopeful you knew my original post was in jest. 
dave s