[Closed] Question about glass shelves

Yes, again.

I have a few Franklin Mint display cases of the type.....

that are sold to and used by the independent retailers
to display their FM models. These shelves are 36' long
and some are as narrow as 8" wide. All use 3/8" glass
and are supported only at the very end of the shelf. On
the other hand I have other shelves that are longer but
made of 1/4" glass. Many of these are really over
loaded with Brooklin Models and I have never had any
trouble.

Thanks for all your input!

Tempered glass is stronger

First, tempered glass hasn't been used for many years in automotive applications. Side windows are laminated safety glass, just like windshields.

Tempered glass is stronger as the temperiang process relieves internal stresses. Like all materials that are formed by cooling from a melt, Plates of glass soldify form the outside in and shrink as they fully solidify. The result is that the outside surfaces are placed in compression while inner areas are in tension. Glass has no strength in tension. Since half of the plate is in tension, it is very weak. These strength of glass is greatly increased if it is heated to just below its melting temperature and cooled slowly -- as this process allows some flow to relieve internal stresses. I work as an engineer in the disk drive indusry, where we spin pieces of glass at over 10,000 rpm.

Be Careful

The difference between 1/4" and 3/8" doesn't seem like much, but the strength of a beam to resist deflection is proportional to the 4th power of the beam thickness. A 3/8" thick glass shelf is actually 5 times stronger than a 1/4" shelf.

I stand corrected, Thanks Fred. Now, can you repeat that in ENGLISH? LOL.