Environmental Control: The Difference between Shop Coatings and Field Coatings

People typically perform better in practice than in actual competitions. This is where the term "choking" in sports come from where athletes are unable to exhibit the same level of performance they've shown in practice during the actual games. A baseball batter for example might be perfectly capable of hitting at least one of three balls thrown his way in practice only to constantly strike out during a regular season game. A figure skater might be able to regularly land a triple axel only to miss the landing during a competition.

It's not just in sports however where this philosophy occurs as there are dozens of situations out there where the difference between being in a controlled environment and an uncontrolled environment could have a measurable impact on performance. In coating application, this philosophy manifests in the divide between shop coating and field coating. For those of you looking to wring the most bang of your buck, understanding the difference between the two and how they impact the performance of the coating should be the first order of business.

Laboratories are one of the most controlled environments you can find in the world. When I was still chasing my Engineering degree in college, I spend quite a bit of time in my campus' anechoic chamber, a room designed to absorb sound and any other electromagnetic waves from both inside the room and the surrounding environment. The chamber is most often used to simulate an environment free of reflected signals and is where my campus' Antenna and Microwave Research Group spend their time as it's the perfect environment for them to conduct their experiments given since there would be no random signals to mess up their data.

In an open field where dozens of cellular signals, Wi-fi networks and a cornucopia of other signals are randomly floating around, it would be nigh impossible to properly collect data on a certain antenna hence the importance of the anechoic chamber. This example perfectly illustrates why in scientific work, it's important to have a controlled environment at all times. True, coating application isn't exactly scientific but given the kind of material the industry regularly deals with, certain considerations have to be taken during the application process.

Coatings tend to have certain conditions during application as they work best under certain temperature, humidity and for the curing process. Powder coating for example need relatively high temperature for their curing process, which can be impractical if applied on the field. This has led to the relatively higher reputation held by shop coating as a controlled environment gives you more freedom during the application. While admittedly shop coating makes the application process somewhat easier, they're not always objectively better than field coating.

A shop coating is broadly defined as a type of coating that's applied in a specific environment. It doesn't have to be an actual shop but typically we're talking about a building or a structure that is purposefully used for coating application. The problem with shop coating is that there's actually no commonly accepted standard for how a shop coating should be. Pretty much anyone can build a shoddy garage, designate that garage as a place for coating application and pass off the result as shop coating because technically, they are.

When you're eating at a restaurant, said restaurant typically has to fulfill some sort of food safety standards to be able to operate as a business. This standard is defined by your local government and is upheld by the numerous food safety inspectors to eliminate or at the very least reduce cases of food poisoning resulting from subpar dining establishments. Scientific laboratories, hospitals and clinics also have their own standards as they too have safety requirements to fulfill but sadly, the same can't be said when it comes to coating applications.

Of course, coating application isn't as crucial as the ones I described above which explains the lack of oversight. As a result, just because a coating is applied at a purpose-built environment, there's no guarantee that said environment is actually properly controlled. You can of course dispatch someone to make sure that the application process has been done up to your standards but that might be impractical since it's not very likely that you could expend that much resource day in and day out.

A field coating is defined as the type of coating that is applied right exactly where the substrate is put into service. This is most commonly seen during a recoating project where a substrate that's been previously coated is given a second chance on life by reapplying the entire coating. Given that the coating is applied on right on the field, there is considerably more limitations you have to deal with in field coating as you have close to no control over the environment. This doesn't make field coating objectively worse than shop coating but field coating is definitely harder.

Just keep in mind however than other than for the reasons described above; shop coating isn't always better because the capability of contractor plays a huge factor when it comes to the finer details of coating application. Each coating for example has their own recommended thickness range, necessitating the use of a paint thickness gauge, and certain coating cures at an alarmingly rapid rate that any kind of mistake could be quite costly to correct. As such, while shop coatings do have certain advantage over field coatings, the actual execution matters more than the nebulous definition of the words and you shouldn't simply assume that just because the coating was applied at a shop, they're of a high quality.