Rear Glass What do they make them with?

[Moparfiend]

Anyone know what they make the rear glass with? Is it layered, tempered or safety? I am referring to new reproduction glass. I am trying to determine the type I have as I might want to grind about an 1/8” for more clearance in a small area. Here is a picture if that helps. If it’s tempered I know I can grind it. I don’t think windshield and rear glass would be tempered though.

 

[dadsbee]

Back glass and side glass are all tempered. Only the windshield is double layer safety glass.

 

[dadsbee]

Also, are you saying that you have a reproduction rear glass? Did you look at the shape of it....

 

[Moparfiend]

Also, are you saying that you have a reproduction rear glass? Did you look at the shape of it....

Yes it’s from Diamond Glas Co. The issue is not the glass but rather my body work. I hand built the sheet metal and the clearance isn’t as much as I would like. The coefficient of thermal expansion for glass is lower than steel by about two to one so I’m probably OK.

 

[Moparfiend]

So if it’s tempered then grinding is out right?

 

[dadsbee]

If it’s tempered I know I can grind it.

So if it’s tempered then grinding is out right?

So which is it??? LOL

I ground my **** AMD side glass and it's tempered !

At least that back glass looks correct! AMD's sure as hell isn't...

 

[Cranky]

Grind it if needed but keep it from getting hot.....and go slow.

 

[dvw]

I've ground glass with tan scotch brite pads more than once. Its slow. Go slow and don't over heat. Never had a failure, front or side glass.
Doug

 

[Moparfiend]

I meant to say that I “thought “ you couldn’t grind tempered glass but I don’t know. I want to take off about 1/8” strip about 3-5 long. I have no clue as what to use and was thinking of calling a local automotive glass shop that does more than slapping them in. Somebody who actually knows.

How the heck can you “grind” glass with a Scotch Brite @dvw ??

 

[dadsbee]

As I said, I ground my door glass down, as the slider holes were over an 1/8" too far in from the edge. Make sure that you're grinding ALONG the edge and not across it! 80 flap wheel..

 

[Moparfiend]

As I said, I ground my door glass down, as the slider holes were over an 1/8" too far in from the edge. Make sure that you're grinding ALONG the edge and not across it! 80 flap wheel..
View attachment 1599501View attachment 1599502

Thanks Wayne. I am wondering if messing with it after it’s been tempered will weaken it? After doing some research I am now more hesitant on messing with it.

 

[dvw]

Using the brown scotch brite roll lock pads I used to grind side glass on Venture vans at the Chevy dealer. They were too long and rattled. Also had to trim the windshield for my 64 Belvedere. Never used a regular flap disc cause I was not sure if to was too aggresive. I'd try it on a junkyard piece of glass and see.
Doug

 

[WileERobby]

How the heck can you “grind” glass with a Scotch Brite @dvw ??

How much glass can a glass grinder grind, if a glass grinder can grind glass ?

 

[Cranky]

Reshaped some ornamental glass using 36 grit but did it by hand and even that created some heat but didn't break it. Used 80 grit next and so on. Lots of time spent on that mess....

 

[Moparfiend]

Reshaped some ornamental glass using 36 grit but did it by hand and even that created some heat but didn't break it. Used 80 grit next and so on. Lots of time spent on that mess....

That was probably plate glass.

 

[Moparfiend]

Using the brown scotch brite roll lock pads I used to grind side glass on Venture vans at the Chevy dealer. They were too long and rattled. Also had to trim the windshield for my 64 Belvedere. Never used a regular flap disc cause I was not sure if to was too aggresive. I'd try it on a junkyard piece of glass and see.
Doug

I am surprised. Thanks for sharing!

 

[Moparfiend]

Ok so I spoke personally to the owner and long time proprietor at a custom glass shop doing all sorts of glass including vintage and restorative automotive glass.
He has personally ground glass edging but follows the rule of 1/3’rd the thickness max. That being said however that even following this rule he has seen the glass fail moments later and weeks later and does not recommend working tempered glass.
My research confirms this both anecdotally and scientifically. I found a website that describes in detail how to machine tempered glass. That involved annealing first then machining and then re-tempering it at like 800F. This is obviously not something most companies can do let alone the lay person.

For those who have done some work successfully on their tempered glass without failure great not judging. There are always exceptions and corner cases. I am simply conveying what I learned for those interested that may read this thread.

MF

 

[Krooser]

Thanks Wayne. I am wondering if messing with it after it’s been tempered will weaken it? After doing some research I am now more hesitant on messing with it.

Don't over think it...grind it using plenty of water to cool it.

I have cut glass to fit top chops... it is easy if you take your time.

 

[Moparfiend]

Don't over think it...grind it using plenty of water to cool it.

I have cut glass to fit top chops... it is easy if you take your time.

Hey Krooser as an engineer that designs space systems and life line communications I am trained to overthink lol. But seriously my point was that grinding tempered glass can cause latent catastrophic failure. It’s a risk that folks should be aware of. In my case I had an alternative work around that I was weighing and the risk of potential failure led me to my alternative solution that was a better choice for me.

 

[WileERobby]

How much glass can a glass grinder grind, if a glass grinder can grind glass ?

Must repeat 5 times quickly before proceeding to read any more posts. Even if you're a woodchuck.