I have found that 10 Mil Coroplast makes a pretty sturdy 4x8' sign.
I have found that 10 Mil Coroplast makes a pretty sturdy 4x8' sign.
A note about material thickness.
Obviously, Ron is using the term "10 Mil Coroplast" as a kind of slang for 10 MILLIMETER Coroplast. This is getting more and more common, to use
mil as slang for millimeter.
A "mil," of course, is a measurement in its own right. It is the equivalent of one-thousandth of an inch, and is written as .001". It is not a metric unit. But, except for a few old-timers, and some people who have worked in the machine tooling industry, the term
mil is rarely heard. My dad, a
pattern maker, used it, but he more often said "thou." My brother and my brother-in-law, both
tool-and-die makers, rarely said "mil," almost always preferring the term "thou."
Obviously, there is no such animal as Coroplast that is only 10 mils in thickness, but context usually makes this clear, as in Ron's post above. Except for one time when my boss got hold of a blueprint that called out cutout aluminum graphics in a thickness of 80 mils. He was momentarily confused, knowing that 80 MILLIMETERS was well over three inches thick. Where was he going to get aluminum that was 80 millimeters thick and how were we going to cut it out? When he realized that 80 mils was only 80 thousandths, an aluminum thickness we kept in stock, his confusion cleared up.
We use mil thicknesses in the sign industry all the time. We just don't call them that.
For example, vinyl sheet is commonly measured in mils, as in, "2-mil high performance vinyl." Obviously, 2-mil vinyl is not anywhere near 2 millimeters in thickness.
Our aluminum thicknesses are commonly in mils, or thousandths. We use 40 mils, 63 mils and 80 mils, for example, written as .040", .063" and .080", respectively. But we usually pronounce these as "oh four oh", "oh six three", and "oh eight oh."
Another industry that commonly uses mil thicknesses is the garbage bag industry. Garbage bag thicknesses may be .7 mil, 1 mil, 1½ mils, etc. Garbage bag makers further complicate matters by using a metric thickness called a
micron, which is one millionth of a meter. Paint film thicknesses are also measured in both
mils and
microns. A human hair is typically 70 microns.
Here are some common thickness equivalents in inches:
One millimeter= .039" (abbreviated
mm)
One mil= .001" (no abbreviation)
One micron= .000039" (abbreviated incorrectly as
um. Proper abbreviation includes the 12th letter of the Greek alphabet, written
μm)
Actually, I think micron is considered an obsolete term.
Micrometer, or British
micrometre, is preferred. Micro means millionth.
Bored in Kansas City,
Brad