All our Al-Ambiq® pot stills are soldered with copper, brass, 100% lead-free tin or silver. Brass, 100% lead-free tin and silver solder is perfectly safe and is commonly used for soldering copper for food use. The main elements in solder we need to avoid are cadmium and lead.
The first union of the pot (boiler) is made by overlapping the sheets of copper, melting the two extremities and then hammering this area on an anvil so that the copper may regain its molecular properties and strength. With high temperatures copper becomes very flexible and limp.
The other sections of the pot are soldered with brass soldering. Brass is an alloy made up of copper and zinc and is well known for it hardness and workability. Brass soldered joints are also hammered on an anvil to strengthen it. All areas of the still that will sustain high temperatures are soldered with brass soldering. The other joints of a still that are not exposed to such high temperatures, as in the pot (boiler) and where hammering is not possible - a 100% lead-free tin solder is used. Tin solder flows easily at a lower temperature and thus there is no need to hammer the copper parts as its molecular structure is not altered. Tin solder is used for the piping and to attach the thermometers. Tin is very good at adhering to copper and is not very soluble which is important as alcohol is a known solvent, and you may have hot alcohol vapors inside a still.
Cadmium free silver solder is mostly tin with a small amount of silver. It uses higher temperatures to get it to flow but it too has excellent adhering properties. Silver solder is used to solder the brass handles and other areas of specific stills. Whichever alloy has been employed in the soldering, our customers can be assured that these will not in any way alter the flavoring, coloring or final results of the distillate.
This technique which is used to join metallic parts, is through the application of heat. It was discovered through efforts to manipulate iron into useful shapes. The technique of welding, which involves inter-layering metal developed from the need to obtain a continuous joint on large steel plates.
Gas welding, arc welding and resistance welding all developed at the end of the 19th century.The first real attempt to adopt welding processes on a wide scale was made during World War I. By 1916 the oxyacetylene process - a mixture of acetylene (gaseous hydrocarbon) and oxygen which produces a very hot flame for welding - was well developed and the welding techniques employed then are still used today.
Soldered alembics require thicker copper sheets and unlike the riveted union construction, the three parts that make up the pot are brass soldered (see soldering), thus there is no need to use a linseed solution to make them impermeable. The areas which are soldered are then hand hammered again so that the copper may regain its resistance and strength.
You should process a distillation of clean water (see cleaning & maintenance) before using your still for the first time.
A rivet is a small metal pin used to fasten flat pieces of metal together. It is a cylinder with forged heads, one formed at the time of making the rivet and the other formed on the hot rivet after it has been inserted. The joining of parts by these cylindrical fasteners passing through holes dates back to Egyptian times.
The ancient Egyptians developed metalworking which possessed an excellence that in some respects has never been surpassed. Throughout Egyptian history the same smiths who worked on precious metals also worked with copper and bronze.
Almost every fashionable Egyptian possessed a hand mirror of polished copper, bronze or silver. Copper pitchers and basins for hand washing were found in tombs. Basins and the bodies of the ewers (pitchers) were hand hammered from single sheets of copper. The spouts were cast in moulds and attached to the bodies by means of copper rivets. All decorative metalwork was executed with a hammer. The separate parts of each item were hammered out separately and were then put together by means of rivets or they were pinned on a solid core (as soldering had not yet been invented). Plates of hammered copper were shaped into statues, the separate parts being joined together with copper rivets. A life-size Egyptian statue of pharaoh Pepi I in the Egyptian museum in Cairo is an extraordinary example of such work.
Connections between metal parts are required in most applications and are a critical part of every design. Rivets have been used in all major metallurgical constructions, including the construction of airplanes, ships, steam engines etc. These connections have proven to be very reliable giving excellent service. Today, in heavy steel fabrication, welding has almost completely replaced riveting as a means of making connections.
Pot stills, (Alembics or Alquitars), have always been made using rivets ever since the Moorish introduced these in the Iberian Peninsula. It is the traditional method of joining the different parts that make up the still. Even though many stills are now soldered, the riveted construction is still preferred by the old folk and by many others.
This traditional method of joining the three separate parts that make up the copper pot (bottom, belly and top) has however improved with the evolution of time. To make the pot totally impermeable a linseed oil solution (linseed oil mixed with other natural ingredients) is applied to all the interior seams. You should process a distillation of clean water with rye flour (see cleaning & maintenance) to remove the excess linseed oil and also to block any passages. However, if after one distillation you can still see some of this solution on the walls of your pot do not scrape it off, DO NOT SCRAPE IT OFF, if you do, your pot may leak. Any excess solution will disappear with continuous distillation and what is left over will not affect or influence whatever you want to distill.