Copper
On this page you will find more information on how copper pans are made, how to tell the different techniques involved in manufacture apart and how these contribute to the quality of the pan. For more information on cooking with copper and the need for a proper tin lining before doing so, please visit our FAQs.
Hammered copper versus modern sheet copper

All early copper vessels were created by hammering the copper into the desired shape. It required great skill and many years of practice in order to deliver perfectly proportioned products and kitchenware created by this method remains the most desirable. An added benefit of the hammering was that once the surface had been perfectly smoothed out, the metal retained the imprint of hammer blows, giving a kaleidoscopic reflection.
As the industrial revolution progressed towards the end of the 19th century, this hand-made production process was gradually replaced by more mechanized techniques. The copper would be rolled into sheets, producing a much smoother finish, unfortunately without the multi-varied reflection. As these techniques were perfected, the copper sheets became ever thinner, as a way to reduce costs. The difference is quite striking when comparing a modern copper pan with a 19th century hand-made one, which can often be a factor 3 or 4 heavier due to the thickness of the copper.
Dovetails

Given that most kitchenware is cilindrical in some shape or form, joints are required to bring the separate pieces of copper together. There are many different ways of doing this, but one of the most common ones for hand-made copper pans is called dovetailing. The coppersmith would hammer the edges of the different pieces to about half their original thickness and then cut slits in the metal, thereby producing small strips of copper that could be interwoven and hammered back together.
The name derives from the way a dove’s feathers overlap and one can find similar, though slightly different, techniques in woodworking. Clean dovetailing is a sign of quality handwork primarily found in pre-1900s copperware as the skill and cost involved in creating joints this way led to its disappearance.
For a much more detailed look at copper joining technique, we can recommend the OldCopper.org webiste.
Rivets

To attach the iron or brass handles to copper vessels rivets were used for making strong joints. Rivets could be made from a variety of materials, but the most common ones are made of copper.
These would be carefully hammered into a round shape to fit the hole. Light hammer marks can often be seen on the surface of the rivet and are a good way of telling modern and antique kitchenware apart.
Initials and numbers

On many of the pots and pans made in 19th century France, you can find initials and numbers inscribed. The numbers were used to tell the pans apart in a busy kitchen. They were either inscribed by the manufacturer, often denoting the diameter of the pan in centimeters, or by the owners.
The latter frequently had their initials placed in the pan. It is said that sometimes this was done to help tell the owner of the pans apart when they were sent to a shop for re-tinning. In some pans you can see multiple sets of initials, tracing the many different hands the pan has gone through.
Stamps

Some of the main manufacurers of French kitchenware marked their products with a company stamp. Among them are such classic companies as Dehillerin, still operating today from it’s store in central Paris, or Gaillard.
Stamps are useful to understand the age and of course provenance of a pan. If you know a certain manufacturer opened for business in 1820, we have a clear line denoting the oldest possible age of the vessel.
Dating
Whenever you try to date a pan, you look at all the elements above to gain a better understanding of its age. Has the copper been hammered into shape by hand or rolled in sheets by machine? How thick is the copper? Have the joints been made with dovetails? What kind of information can we glean from initials and manufacturers’ marks?
Putting all these together you can come up with an approximate age. There are some complications, though. As industrialisation was a gradual process, it can be difficult to ascertain the exact age purely based on coppersmithing techniques. Workshops located in the countryside may have been slower to adopt modern techniques, sometimes lagging several decades behind the centers of coppermaking. As a result many of the dates we use are approximate and not down to the individual decade.