# Bullet Proof Glass **URL:** \ **Category:** Factual Questions\ **Created:** [May 11, 2016, 1:17am UTC](https://boards.straightdope.com/t/bullet-proof-glass/754518 "2016-05-11T01:17:56Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [May 11, 2016, 1:17am UTC](https://boards.straightdope.com/t/bullet-proof-glass/754518/1 "2016-05-11T01:17:56Z")
I need an expert or someone knowledgeable about bulletproof glass. Is this material prone to develop what appear to be small, internal scratches, perhaps thermal stress cracks, but very short and small, appearing as a cluster of such parallel scratches. Maybe some SDoper knows what I mean? I need to know if these are really defects or natural aberrations of the material? ---
**Author:** ![Airman\_Doors\_USAF](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Airman\_Doors\_USAF](https://boards.straightdope.com/u/Airman_Doors_USAF)\ **Post date:** [May 11, 2016, 3:00am UTC](https://boards.straightdope.com/t/bullet-proof-glass/754518/2 "2016-05-11T03:00:57Z")
It’s a laminate with alternating layers of glass and polycarbonate, so internal defects like apparent scratches are perfectly reasonable. Try to put Saran Wrap on a glass pane and then put another piece of glass on top of it and you’ll see how hard it is to perfectly layer things. ---
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [May 11, 2016, 4:10am UTC](https://boards.straightdope.com/t/bullet-proof-glass/754518/3 "2016-05-11T04:10:12Z")
> [@Airman\_Doors\_USAF](#): > > It’s a laminate with alternating layers of glass and polycarbonate, so internal defects like apparent scratches are perfectly reasonable. Try to put Saran Wrap on a glass pane and then put another piece of glass on top of it and you’ll see how hard it is to perfectly layer things. That’s great to know how it can very well happen! Thanks! ---
**Author:** ![Me\_Billy](https://avatars.discourse-cdn.com/v4/letter/m/e480ec/32.png) [@Me\_Billy](https://boards.straightdope.com/u/Me_Billy)\ **Post date:** [May 11, 2016, 3:58pm UTC](https://boards.straightdope.com/t/bullet-proof-glass/754518/4 "2016-05-11T15:58:19Z")
It seems to me that older bullet proof glass was “glass” whereas newer is plastic. Anyway there seems to be different types of this “glass”. Following is a link which says there are 3 types now and there is a 800 number at the bottom, might want to call and ask… [Bulletproof Glass Through The Ages - The History of Bulletproof Glass | Visual.ly](http://visual.ly/bulletproof-glass-through-ages-history-bulletproof-glass) More… [The History and Evolution of Bulletproof Glass](http://appleglasscompany.com/the-history-and-evolution-of-bulletproof-glass/)