
Glass Dates
Original window glass is typically marked with details of the manufacturer, including a logo and an indication of manufacture date.
Common manufacturers are Triplex, Indestructo and Armourplate. An example for each type is given for the date of “first quarter 1962”.
Triplex
Dot above ‘TRIPLEX’ indicates the quarter of the year:
T | R | E | X |
1 | 2 | 3 | 4 |
Dot below ‘TOUGHENED’ indicates year in the decade:
T | O | U | G | H | E | N | E | D | No dot |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |

Sample date marking for Triplex (first-quarter 1962).
Indestructo
Date is derived from the left pair of letters below ‘INDESTRUTCO’, e.g. “BT”
The first letter is for the quarter of the year, based on ‘BRIT’:
B | R | I | T |
1 | 2 | 3 | 4 |
The second letter is for the year, based on ‘INDESTRUCO’ (missing second T), however not in sequence as per table:
S | T | R | U | C | O | I | N | D | E |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |

Sample date marking for Indestructo (first-quarter 1962).
Armourplate
A dot below 'SAFETY' indicates the quarter of the year:
S | A | F | E |
1 | 2 | 3 | 4 |
A dot above 'ARMOURPLATE' indicates the year in the decade:
A | R | M | O | U | R | P | L | A | T |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |

Sample date marking for Armourplate (first-quarter 1962).
Tuftest Safety Glass
Sliding window glass on some cars is marked 'Tuftest Safety Glass'.
Currently no information is known about this glass marking. If you have something to contribute, please let us know.
Last updated 18 March 2021