While it had previously been common to have Zippos with authorized badges, unit crests and division insignia, it became popular among the American soldiers of the Vietnam War to get their Zippos engraved with personal mottos.
These lighters are now sought after collector's items and popular souvenirs for visitors to Vietnam.
The appearance of the word "Zippo" in the bottom stamp provides another clue to dating.
There have been three major changes, as show below.
Even prior to the coding system we can go some way to identifying the approximate year of manufacture, as the stamping on the bottom has changed slightly over the years. From 1936 until 1953 the bottom will have "PAT2032695 MADE IN U. A." Lighters made in 1953-1955 will have PAT 2517191 PAT. PAT 2032695 Lighters (1933 - 1953) PAT 2517191 PAT. On the image below we can clearly see that there are four dots, either side of the word Zippo. 1966-1973 Dating guide From 1974 until 1981 the solidus (now commonly referred to as a forward slash) was used.
Lighters assembled at the Canadian factory are covered here - Dating Canadian Lighters As lighters are meant to be used, coins or keys carried in the same pocket can cause scratches on the bottom of the lighter so it is necessary to look very carefully at the bottom, as the marking can be quite difficult to make out. The first lighters (1933 to 1935) can easily be identified by the words "PAT PENDING MADE IN U. In 1979 an error was made and the slash was removed from the left instead of the right 1974-1981 Dating guide 1982 saw the use of the reverse solidus (or backslash) and this continued in use until mid 1986.
The first markings were added in 1957 and overlapped into 1958.While the information for dating a Zippo is widely available, it isn't that handy to find it all in a single location.This should provide the information to fix a relatively precise date for any Zippo lighter.Thousands of different styles and designs have been made in the eight decades since their introduction including military versions for specific regiments.Since its invention Zippos have been sold around the world and have been described "a legendary and distinct symbol of Americana".Since 1955, most Zippo lighters have carried a date code stamped on the base.Originally this was intended as a quality control record, so that lighters returned for repair could be identified as to when they were manufactured and if, for example, a number of lighters were returned with the same fault then Zippo could identify a possible defect in the manufacturing process or even a supplier of one of the components. As there were some alterations to the positioning of the text on the bottom line, some codes were used twice, therefore close attention should be paid to the text on the bottom line for lighters with 7 or 8 dots. 1955-1965 Dating guide The next set of codes used upright lines either side of the word Zippo. Again 8 lines were used for the first year of the series, with one line being removed each year.Since its inception Zippo Lighters have been almost exclusively manufactured in the United States, with the exception of those manufactured in Niagara, Canada (an operation that has since been shut down). Blaisdell founded Zippo Manufacturing Company in 1932, and produced the first Zippo lighter in early 1933, being inspired by an Austrian cigarette lighter of similar design made by IMCO.Zippo lighters became popular in the United States military, especially during World War II — when, as the company's web site says, Zippo "ceased production of lighters for consumer markets and dedicated all manufacturing to the US military".As with most collectibles, the date of manufacture of a Zippo lighter often affects its value.Valuable information on the bottom of every Zippo windproof lighter can help you determine its date of manufacture.