The quick answer to this question is simply no, once glass is tempered it can no longer be altered. All fabrication to glass must be done prior to the tempering process.
Tempered glass is a type of safety glass and is commonly used in most everyday applications.
- Glass that is in, or next to doors, is required to be tempered
- If the glass is located less than 18” from the ground it must be tempered
- All glass that makes up a shower door must be tempered for both safety and strength
- Most recent building codes are requiring that any windows in a bathroom are required to now be tempered
- Furniture with no underlying support (such as outdoor patio tables) need to have tempered glass
- Most of the glass in your car is tempered aside from the windshield
Tempering machines are both large, expensive to purchase, and expensive to run. This limits the tempering process to larger factory operations, which most retail end glass companies purchase from.
The process of tempering is when the glass goes through the oven on a conveyor belt, is heated to almost its melting point, and then quickly cooled down with blasts of air.
Tempering factories have large facilities setup to completely cut, drill, polish, and miter the glass prior to running through the furnace. Tempering is simply the final step to the entire process.
A stamp or “bug” is etched in the corner of the glass which has several identifying marks. One being the factory that completed it, and other certification markings.
After tempering is compete the glass can no longer be altered. Trying to do so will end up with the glass shattering into thousands of pieces, a big mess, and a potentially dangerous situation. So even if you need to drill holes in your glass shower enclosure, its best to plan for that before the glass is tempered.