Gluing plastic on to the rear view mirror of a car is one of the most commonly-occurring car maintenance requirements. Gluing plastic on a glass surface might seem demanding but it can be easily done, using the following information.
Cleaning Gluing Surface is Vital
This is the first and most important part of this project. You need to ensure that the spot chosen for gluing the plastic is thoroughly cleaned. Any remaining debris can seriously hamper the bonding process of the glue. Ideally, you should clean the spot with a glass cleaner or any branded car-cleaning solvent. If there is any trace of oil or grime, you can use anti-grease cleaners that are recommended for automobiles.
However, the cleaning becomes a bit more demanding if there are traces of any adhesive from a plastic that was previously stuck on the same spot. For removing the traces of adhesive, use a car-wash detergent. It is advised that you always use a soft, lint-free cloth for wiping the rear view mirror to prevent scratches.
Sanding & Preparing Gluing Surface
This may sound a bit strange, but you need to roughen-up the gluing surface in order to make the adhesion more comprehensive. This is because a rougher surface provides lesser friction. This means that the glued plastic is less likely to slip every time the car is jerked upon braking.
Further, the sanding of the gluing spot helps to create microscopic depressions that can sustain a greater amount of the adhesive. Ideally, you should use a low-strength grit paper for sanding the cleaned, glass surface. A 120-grit sandpaper is recommended for this purpose.
Using Hot Glue Guns: Preferred for Gluing Plastic onto Rear View Mirrors
Glue guns are recommended for such gluing requirements. Plastic and glass are best bonded with the hot or molten version of glues that are specifically retailed for this purpose. These glues are applied though a hot glue gun. A glue gun should be warmed according to the packaged instructions.
Before applying the gun, it is vital to test the consistency of the warmed-up glue. You can do this by squeezing-out a few drops of the hot glue on a piece of paper. Ensure that the glue isn't so hot that it vaporizes upon ejection. It shouldn’t develop an outer crust immediately. The glue drops should spread slowly upon the paper without burning it.
Once the required consistency has been achieved, squeeze a few drops of the hot glass glue upon the cleaned spot. You shouldn’t stick the plastic immediately. Allow the glue to cool for about a minute. During this cooling period, the glue bonds with the glass surface. When using hot glue gun, always keep a basic first aid kit or a bowl filled with ice cubes to take care of accidental burns.
Optional Glues: Using Ultraviolet Glue or Silicone Glue
Besides hot glue, you can consider two other options—ultraviolet glue and silicone-based glues. Please note that the glass surface has to be prepared in a similar manner for either of these glues too. However, the method of applying the glue is a bit different.
When using ultraviolet glue, you need to do the gluing under direct sunlight. There is no cooling time required here. You can glue the plastic objects immediately after spreading the gluing. However, the glued surfaces need to be exposed to direct sunlight for at least about two hours for proper bonding. Silicone-based glues have no waiting time or drying time either.