Some things are hard to understand. Movies about time travel are one, specifying sheet metal thickness in gauge numbers is another. Now we&#;re metal fabricators, not quantum physicists so let&#;s jump straight to the second one and talk about gauge.
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Here in the US we measure in feet and inches, unless we&#;re talking about the height of horses or the thickness of sheet metal. Then we use hands for horses and &#;gauge,&#; written as &#;ga&#;, for metal. Gauge is a dimensionless number sometimes spelled &#;gage.&#; and confusingly, it works backwards. Usually a bigger number means there&#;s more of something but 18 gauge steel is thinner than 16ga, not thicker.
Sheet metal is specified in gauge, so rather than design in fractions of an inch you should really be specifying ga on part prints. You should also know about gauge when discussing sheet metal with your friendly Indiana-based metal fabricator. That way, if we suggest something like switching from 14 to 16ga to tighten a bend radius or save weight, you&#;ll know what we mean.
Gauge numbers run from 3ga (0.&#; thick,) up to, (or should that be down to?) 38ga (0.&#; thick.) Typically though, most sheet metal folks switch over to talking about plate for thicknesses greater than 10ga or 0.&#;.
You can find a gauge-to-inch conversion table at several places online. While looking at those you might also notice that the conversions are different for metals other than plain steel. That&#;s because gauge is derived from weight.
Using &#;gauge&#; as a measure of thickness goes back to the beginning of the industrial revolution. Wire drawers (people who produce wire,) needed a way of quantifying what they were selling, and the easiest method was weight. But just asking for fifteen pounds of wire without specifying the thickness wasn&#;t very helpful, so the drawers would quote diameter based on the number of draws performed, and this became the gauge. This is also why a higher gauge number correlates with thinner material. Each drawing reduced the diameter, so more drawings meant thinner wire.
As steelmakers started rolling their product into sheet they found it was easier to measure weight than thickness. So, similar to wire, sheet metal could be sold at a weight per unit area, with thinner material weighing less per square foot. The easiest way they found to specify sheet thickness was the gauge number system of the wire drawers.
Back in the 18th and 19th centuries standards were pretty much nonexistent. Instead, each manufacturer developed their own. Over time though these were harmonized, bringing about Standard Wire Gauge (SWG) for wire, Manufacturers Standard Gauge (MSG) for steel, and American Wire Gauge (AWG) for nonferrous metals.
One confusing aspect of gauge is that neither thickness or weight per unit area change by a constant amount as you move from one number to the next. In fact were you to graph the numbers you&#;d see what&#;s called an &#;exponential decay curve.&#; In other words, the difference between successive gauge numbers becomes less as gauge increases. For example, the difference between 10 and 11ga is 0.&#; while between 35 and 36ga it&#;s only 0.&#;.
This difference goes back to the wire drawing origins of gauge. It&#;s down to the amount of reduction achievable. To make thin wire the drawers wanted to reduce the cross section as quickly as possible, but there are metallurgical limits on how much can be done in one pass. So over time they determined the optimal number of drawing steps needed, which is what lead to this exponential decay curve.
Think too hard about the logic of traveling through time in movies and it&#;ll fry your brain. That&#;s why, to quote Bruce Willis in Loopers, &#;&#; if we start talking about [time travel] then we&#;re going to be here all day talking about it, making diagrams with straws.&#; Sheet metal gauge on the other hand, is quite logical, even if you have to go back in time to understand its origins.
We&#;ve all been there.
The desire and effort put into choosing the right device such as a coating thickness gauge can leave you disappointed and frustrated knowing you&#;ve given it all you have.
A coating thickness gauge is an essential tool for assessing the quality of a coated component or a piece of equipment like a vehicle. It gives you specific data like how long the vehicle has before corrosion sets in. This kind of information can help you assess the vehicle&#;s value and consequently allow you to bargain the price more accurately.
This guide contains all the information you need to choose the correct coating thickness gauge, including various applications and typical buying considerations.
Want to know more? Then let&#;s dive right in.
I. What are the Types of Coating Thickness Gauge?
Coating thickness gauges are sometimes referred to as paint meters. However, their function is to measure the thickness of coating material to ascertain the level of protection of the coated material, often known as the substrate. Interestingly, there are three general categories of coating thickness gauges, including digital, destructive, and mechanical coating thickness gauges, all of which have specific application areas.
Digital coating thickness gauges are often very versatile as inspectors use them to measure almost any material&#;s coating thickness, including ferrous and non-ferrous materials. They are also very accurate with a repeatable thickness measurement.
On the other hand, destructive coating thickness gauges are suitable for multi-coat paints and non-metallic substrates. However, they are not ideal for risky job areas like underwater or highly flammable environments where mechanical coating thickness gauges are most suitable.
II. What are the Applications for Measuring Coating Thickness?
Measuring the coating thickness on components is often found in different industrial and domestic operations, including
For Typical Coating Materials
These materials include paints, plastic, and enamel.
Insulating Coatings
Paints, enamel, plastics, and ceramics acts as insulating coatings on components that inspectors must check against design requirements.
Non-Ferrous Coatings
include chrome, brass, lead, zinc, and copper.
Ferro-Magnetic Coatings
Electroplated Nickel is a typical example of a ferromagnetic coating.
For Typical Substrate Materials
Includes both insulating substrates and non-ferrous substrates like Tin and aluminum.
Insulating Substrates
Plastics, epoxy, and glass are often used as insulating substrates and need coating thickness gauges to ascertain quality.
Non-Ferrous Substrates
Aluminum, bronze, and copper are typical examples of non-ferrous substrates that require coating thickness gauges.
Ferro-Magnetic Substrates
Using electroplated Nickel for ferromagnetic coatings often requires coating thickness gauges for quality assessment.
For Typical Coating Measurement Application
Different applications require coating thickness gauges, including insulation coatings with materials like paint, plastic, and enamel.
Automotive Refinishing Detection
Finished surfaces in the automotive industry are critical to ascertain the quality and value of the product. A poorly finished surface is seen as having low value.
General Industrial Measurement
Industrial measurement of coatings, especially on metallic substrates, are common, especially in anti-corrosion applications.
III. What to Look for When Buying a Coating Thickness Gauge?
Deciding on the most suitable coating thickness gauge for assessing the quality of coatings can sometimes be challenging. You&#;ll need a thorough understanding of the inspection requirements. Most importantly, careful consideration of some critical factors and features is essential for this process. Here are the vital elements you should never fail to consider when buying a coating thickness gauge.
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&#; Coating thickness gauges with higher resolutions often provide a better visual representation of the thickness measurement for the inspector. For instance, a 0.001 mil resolution will give more details than a 0.001 mil resolution.
&#; The speed of coating thickness gauge in taking readings helps achieve a faster inspection. A device that can take 50 to 60 readings per minute will cover much ground in the shortest possible time and finish the assessment quicker.
&#; Usually, the maximum and minimum thickness measurable by a coating thickness gauge determines its range, and its accuracy is the level of acceptable tolerance for error built into it. These parameters are essential when looking for a suitable coating thickness gauge. The higher the accuracy and range, the better the device though this might also mean a higher price. Typically, the accuracy of a coating thickness gauge often comes as ±(3%+1um) but can change based on the material under inspection
.
&#; Identifying the material that a coating thickness gauge can measure is equally important as some are specifically suited for single materials like aluminum or steel. Still, some are designed to allow you to check both materials and even more materials so you can do more inspections.
&#; Coating thickness gauges get power from different battery types, including AAA and rechargeable batteries. But rechargeable battery-powered devices are preferred for obvious reasons like the convenience and charging options, including USB chargers. Still, other coating measurement devices do not need batteries at all.
&#; Different types of coating thickness gauges utilize different types of reading output. While some have a side scale to indicate reading values, others have a display screen for you to see the readings. Though devices with a display screen are better for the sake of easy usage, you need to ensure that the readings displayed on the screen are also easy to read without being crowded.
&#; The device&#;s portability is also a critical factor to consider in your choice of a coating thickness gauge as it makes it possible to carry around without any trouble. Hence the weight and size of the device you chose will significantly determine the portability of this device.
IV. How to Choose a Coating Thickness Gauge?
Many factors often determine the choice of a suitable coating thickness gauge. However, the type of coating material and the thickness measurement method often dictate these factors&#; most critical. You&#;ll usually be the judge of the most critical factors to consider in choosing any coating thickness gauge for your inspection needs. Here are the essential elements for selecting an accurate coating thickness gauge.
&#; A supplier&#;s track record or brand is crucial in choosing a coating thickness gauge. Some brands are known for low-precision coating thickness gauges, often suitable for domestic use. Choosing such brands or suppliers for industrial applications might not be the best decision.
&#; The measurement occasion often refers to the flatness and width of the surface. A high-precision coating thickness gauge might be most suitable when these parameters are substantial. On the other hand, smaller objects will only require a general coating thickness gauge with a more general precision that will suffice.
&#; Size matters. And in selecting a suitable coating thickness gauge, the size of the material under examination is an essential consideration. Certain coating measuring devices are ideal for small bolts, screws, and nuts. But when it comes to bigger components, a more convenient coating thickness gauge will be required. You might even need fixtures to make the operation more suitable for massive objects.
&#; Choosing a coating thickness gauge with a suitable measurement range is essent
ial.However, the type of coating on the object will significantly affect the measurement range you will require for a coating thickness gauge. Mostly, a thickness range of 0 &#; μm is often acceptable, but for thicker coatings used in an anti-corrosive and fireproof application, a thickness range of up to 0 &#; μm might be required.
Depending on your purpose of using a coating thickness gauge, the level of accuracy you require might vary considerably and might also affect your choice of a coating thickness gauge. Generally, home or domestic use of coating thickness gauges doesn&#;t require the highest level of accuracy, and a cheap entry-level device might be enough. However, industrial usage often requires higher accuracy, and a more specialized coating thickness gauge will be suitable.
&#; Your budget is a critical determining factor when choosing a suitable coating thickness gauge. The price a supplier offers to give you a coating thickness gauge will be an essential determiner for making your choice, as your budget is a primary consideration when choosing a coating thickness gauge.
Choosing a coating thickness gauge that is difficult to use can be a deal-breaker when choosing a coating thickness gauge. A more intuitive device with a readable display gives you less stress while measuring the coating thickness. It also makes you more effective and faster while carrying out your inspection. Additionally, a new user will quickly understand how it works without going through rigorous training to use it.
ome coating thickness gauges do not offer any form of compatibility with a computer. As such, you only have the option of entering the data you&#;ve collected into a sheet of paper or a hardcopy book. However, some manufacturers give you proprietary software that allows you to connect your measuring device with your computer so that you can enter the data you&#;ve collected directly into your computer.
&#; You might have to consider other factors such as instrument automation, a minimum, and maximum measurable area, minimum measurable curve, and data collection ability of a coating thickness gauge. These considerations are also crucial in choosing a suitable coating thickness measuring device for your peculiar quality assessment needs.
V. How to Perform the Calibration with Coating Thickness Gauge?
Like most devices and equipment used in assessing the quality of a component, the coating thickness gauge has some level of error tolerance built-in. It will often need periodic checks to ensure that this tolerance has not been exceeded. Consequently, you&#;ll need to perform a calibration process to ensure you keep your coating thickness gauge within an acceptable error tolerance limit.
To perform the calibration of a coating thickness gauge is pretty easy and quick as most manufacturers provide accompanying software that can guide a user through the process.
The first step is to take about 5 to 10 measurements on an uncoated object to determine a zero point for the coating. Then set a calibration foil on the uncoated object and repeat the exact 5 &#; 10 measurements to get the nominal value as much as the film thickness corresponds to the object&#;s coating, the better the accuracy of the coating thickness gauge.
VI. What is the Detection Process of Coating Thickness Gauge?
Depending on whether the material under examination is ferrous or non-ferrous, the detection principle of a coating thickness gauge can differ significantly. However, the detection process of a coating thickness gauge is the same regardless of the material type.
The detection process often begins activating the device by pressing a power button or a switch. It might take a few minutes for the device to automatically calibrate itself to its surroundings to get accurate readings, for which you&#;ll have to wait. Next, set your desired configurations on the device with the appropriate buttons and carefully place them on the object for inspection. When you are set, simply start the operation.
&#; Related Article: How to Check Car Paint Thickness with a Coating Thickness Gauge?
Conclusion
In conclusion, choosing a suitable coating thickness gauge shouldn&#;t be difficult and frustrating if you know what factors to consider. Depending on the type of material, the risk associated with the work environment, and the level of accuracy you desire, your choice of a coating thickness will often be between a digital, mechanical, or destructive coating thickness gauge. However, the most important consideration you should use in making your choice includes resolution, speed, accuracy, measurement range, and ease of use. Don&#;t also forget to consider your budget, as this is, in most cases, the most critical factor.
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