Aluminium foil has a shiny side and a non-shiny side. Rolling aluminium in the final rolling process produces a shiny side. It is difficult to produce rolls with a gap fine enough to roll a single foil. For the last pass, two sheets are rolled simultaneously to double the thickness of the roll. When the sheets are later separated, the two inner surfaces are matt and the two outer surfaces are glossy.
Aluminium foil rolls and sheets are available in various thicknesses, widths and lengths. Manufacturers often make the width and length of foil rolls easy to find, but the thickness of the foil is usually not advertised. Most manufacturers use terms such as standard load, heavy duty and extra heavy duty to describe foil thickness. It is not possible to find the actual thickness from the foil box or the manufacturer's website.
Let's look at some common foil thicknesses. Understanding how to measure foil is the first step in obtaining foil thickness. Becoming familiar with the measured increments will help to understand the thickness once obtained. Aluminium foil manufacturers measure the thickness of aluminium foil in mils. Here is what mils means and how mils are displayed numerically.
1 mil = 1 thousandth of an inch.
1 mil value = 0.001
Most standard duty foil rolls are economical foil rolls of aluminium foil for commercial and domestic use. Standard duty foil rolls for domestic use are typically 75 feet to 250 feet long and are available in a variety of widths. Most foil rolls marked "Standard Duty" are between .0004 and .0007 thick. At best, they are slightly over or half a mil thick.
Some users prefer thin, flexible foils for a variety of domestic use and commercial needs. Most standard or economy foils are usually much less expensive than heavy or extra heavy duty foils. Some users do not prefer standard foils due to their tendency to tear and burn when baking.
By far the most common foil used for domestic and commercial purposes. Most home users buy 75ft rolls of Reynolds foil or similar brands for domestic use. Heavy duty foil provides extra strength and tear resistance. Many chefs use it for baking, grilling and storage. Most foil rolls marked " Heavy Duty" are between .0008 and .001 thick. The extra three thousandths of an inch makes a big difference for a variety of applications.
Thicker thicknesses are hard to find, but some manufacturers do produce extra heavy duty foil. It has excellent tear resistance and can be used with all heavy duty and standard foils. Most foils marked "extra heavy duty" are between .0011 and .0016 thick. Foils thicker than this are often difficult to find and require custom orders.
The easiest way to measure the thickness of aluminium foil is with a micrometer. A micrometer can measure small, precise measurements. There are several micrometers available. The best to use is the outer diameter micrometer using the inch system. The user can easily measure the thickness of the foil without having to convert to metric.