when buying vinyl, what is :
thickness - mil vs micron. How many mil = micron ? I see some mention 1 or 2 or 2.5mil and others 70, 80 micron etc . .
Mil refers to the US or imperial system of measurement and is 1/1,000 of one inch. 2 mil, for example, is .002". Micron refers to the metric system and is 1/1,000,000 of a meter.
premium (951) "cast" vs high performance (751) "cast". What's the difference between "cast" and "cal (651, 641, 631 etc . . ?)
Cast and high performance used to mean the same thing. High performance, however, may have become co-opted by some manufacturers to mean any film that has a longer life than another film.
Cast film is manufactured by liquefying the vinyl using heat and chemicals and then "casting" it into a sheet. The result is that the sheet is very stable and shrink resistant in its final form. Cal or calendared film is manufactured from vinyl in the form of a soft dough. It is run through rollers to form a sheet. The result is that the sheet is NOT very stable and NOT shrink resistant in its final form. Rather it will always tend to shrink back to its original form.
Casting vinyl is a more expensive process than is calendaring it. It is an inherently superior method which results in a longer life. The results are also thinner than calendared film making it more suitable for curved and uneven surfaces when applied. Most calendared films have chemicals added into their formulas intended to extend the life of the film to compete with the superior features of cast films. The results are mixed.
Think of cast vinyl as a perfect coat of paint with adhesive on its backside. When applied to a surface, it takes on the form of the surface and dries without shrinking. As it ages, it has no tendency to shrink thus breaking its bond to the surface it has been applied to.
