Windscreens are laminated and hold together when cracked, so they make safe panels for cold frames and greenhouses; side windows are tempered and break into small cubes; mirrors signal with reflected sunlight, and headlight reflectors focus it. Concentrated sunlight burns skin, ignites tinder and damages eyes, so never look at the focus or flash a bright reflection into anyone’s eyes, and leave the high-voltage ballasts of xenon headlamps alone.
Glass and polished metal are among the hardest things to make after a collapse. A car carries large panes, several mirrors and curved reflectors that all work without electricity.
Different Glass In The Same Car Has Different Uses
Windscreen and window glass (parent article).
- Windscreens are laminated: two layers of glass with a plastic interlayer. They crack but hold together, so they are useful as greenhouse panels, cold-frame covers and table or shelf surfaces.
- Side windows are tempered and shatter into small cubes. They are not useful as flat panels, but the cubes can be recycled by melting in a kiln.
- Rear windows may be tempered or laminated depending on the vehicle.
Mirrors. Side and rearview mirrors are flat or slightly convex. Uses include signalling with reflected sunlight, directing sunlight into dark spaces, parts for improvised solar cookers, and periscopes for looking out without exposing yourself. A large mirror combined with a dark container makes a basic solar water heater (parent article).
Headlights and reflectors. Headlight reflectors are parabolic mirrors that focus light, or heat, to a point. Aimed at the sun, one can concentrate enough heat to ignite tinder. LED headlights draw little power and give good light from a 12 V battery. Turn-signal and taillight lenses are coloured filters for signalling systems.
What You Need
- Duct tape, a putty knife and a utility knife or cutting wire for glass that is glued in.
- Cut-resistant gloves and eye protection.
- Screwdrivers and sockets for mirrors and lamps.
- A padded place to stand panes on edge.
Method: Remove, Handle, Apply
Step 1: Tape and remove. Tape an X over the glass. Windscreens are held by adhesive, so cut the bead from outside or inside with a cutting wire or a long knife, working slowly and keeping the glass supported.
Step 2: Take side glass by removing the door trim and lowering or unclipping the window, then lifting it out.
Step 3: Mirrors and lamps. Unscrew the housings. Handle bulbs with a rag, and treat the glass envelope as fragile.
Step 4: Signal with a mirror. Hold the mirror near your eye, spread two fingers in a V around the target, and tilt the mirror until the reflected spot lands between your fingers. Flash in short bursts. Do not aim the reflection into anyone’s eyes.
Step 5: Use a reflector as a concentrator with care. Point it at the sun and find the focus with a piece of dark wood or paper held at the hot spot, never your hand or face. A blackened pot at the focus will heat water slowly.
Step 6: Store panes on edge, padded, protected from knocks.
Common Mistakes
- Trying to cut or reshape tempered glass. It bursts into cubes.
- Looking into the focus of a reflector. It can blind.
- Leaving a concentrator unattended in the sun. It can start a fire in whatever is at its focus.
- Breaking a windscreen to remove it. It makes a mess and loses the pane.
Safety
Concentrated sunlight, broken glass and high-voltage lamps
A reflector aimed at the sun produces a hot spot that ignites paper and wood and burns skin; keep it pointed away from people, animals and dry vegetation when it is not in use. Never stare at a bright mirror reflection or at the focus. Broken glass cuts deeply, so wear cut-resistant gloves and eye protection. The control units of xenon (HID) headlamps generate high voltage; do not open them.
What’s Next
- Learn next: Fluids: Oil, Coolant, Brake Fluid — the other things a car holds
- Combine with: Glass Salvage & Handling — general glass handling