Tip: You cannot drill tempered or toughened glass. If you do the glass will shatter into tiny little pieces for safety reasons. Glass doors and the panes of glass within door openings are usually tempered/toughened glass. Also commercial and residential windows that start at the floor or close to the floor are tempered/toughened glass. Tip: If you intend to repair Patio Doors or tempered/toughened glass windows you will need follow the instructions in step 5. Defogging Patio Doors or Tempered/Toughened Glass.

1.1 Tip: Access holes MUST be drilled from the outside. For the defogging process to work the window MUST vent to the outside air in order for it to dry out and stay dried out.

1.2 Tip: Always drill the bottom hole first. Place the drilling template at a roughly 45 degree angle at the lowest corner of the window and secure it with any type of sticking tape. Using the template will give you the position of the hole and also protects the glass from scratching if you slip when drilling the hole.

1.3 Half fill the Solution Sprayer tank attached to the the custom Dremel water coolant sprayer with clean water and then pump the handle to build pressure.

1.4 After installing one of the glass drill bits into your Dremel rotary drilling tool, with water spraying onto the template from the custom Dremel water coolant sprayer, start drilling.

1.5 Tip: Every few seconds allow the drill to pull away slightly from the glass. This will allow the water to flush the hole out and remove the glass dust from the glass drill bit. You are also adding coolant to the glass drilling process which will substantially increase the life of the glass drill bits.

1.6 Tip: Take your time and ensure the glass dust is being washed out of the hole as you drill. If glass dust is allowed to build up on the drill and in the hole, it will be sprayed into the unit when you break through. This white glass dust is very difficult to remove. It is vital that when the drill breaks through the glass into the cavity of the unit it is done very gently and without force.

1.7 When you have drilled all the way through, remove the drilling template, and flush the hole and area around the inside of the unit with the water feed to make sure all the white glass dust is washed down. Do not worry about the water entering the window.

1.8 Tip: Check the hole for size. The hole needs to be just large enough for the venting plugs to slide securely into the window. If needed, continue to sculpt the hole with the cutter to clean up the hole and make it the correct size. Always use the water feed and do not worry about the water entering the window.

1.9 Now move to the top of the window diagonally from the bottom hole. Drill another hole by carrying out the same process.

1.10 Tip: When you break through make sure ALL the dust is washed down to the bottom of the unit IMMEDIATELY. Do not worry about the water entering the window. It may take quite a bit of flushing to ensure all the dust is washed from the window glass, but if you allow it to dry onto the surface it is almost impossible to remove later.