We have found the following method to be the best way to clean, prep and glue glass surfaces:
- Wash the glass with warm soapy water (don't use window cleaners as they contain surfactants). Some people even use their own spit to clean the surface of the glass before gluing. You can also use cerium to clean and polish the surface.
- Rub the glass surface with wet whiting immediately after washing to remove any soap residues. Whiting is calcium carbonate, also called talc, and is usually available from a ceramic supply company. Rinse and dry well.
- Clean the glass surface with a lint free towel and pure isopropyl alcohol (IPA). An acceptable IPA is available from drug stores at 70% IPA concentration, but the best cleaner is 99% IPA. Don't use rubbing alcohol, as they generally have oils the mixture.
- Pre-treatment with A-1100 is necessary for maximum bond strength between the HXTAL and the glass. Hand rub the glass surface with a lint-free wipe that has been wetted with the A-1100 amino-silane. The A-1100 is contained in a 99.99% pure IPA solution that will leave an oily looking film on the surface of the glass as the IPA evaporates. This remaining film is the actual A-1100; it will "disappear" in the glue joint as it helps the HXTAL truly bond to the glass with as much strength as is possible. The glass should be bonded with the HXTAL as soon as possible after applying the A-1100. It is not recommended to wait more than 15—20 minutes.
- Curing begins the minute the resin and hardener are mixed. HXTAL cures (sets) very slowly– one of the wonderful properties of this adhesive. Curing takes about 7 days at room temperature, or about 24 hours if the ambient temperature is raised between 90°–110°F. To speed curing time, we place the glass on a shelf in a wooden box with 1 or 2 light bulbs beneath the shelf. This provides sufficient heat to gently but significantly accelerate the cure time of HXTAL. Be sure it doesn't get too hot if you use this method. After 18—24 hours in the "hot box", let it stand until thoroughly cooled to room temperature before grinding and polishing of glue joints. Cooling overnight is effective. These warm temperature cures do not alter glue qualities, although excessive temperature can cause the glue to turn slightly yellow in color.
The unused HXTAL epoxy mixture can be placed in a sealed container and frozen. This frozen mixture can then be thawed and used over a week's time as normal, although it may be slightly thicker than when it was frozen. When thawing, allow the mixture to thoroughly raise to room temperature before opening the container, as the cold glue can condense, causing the water to contaminate the glue. This thawed mixture can also be mixed with fresh resin and hardener (parts A & B) for a new, larger batch of glue.