The benefits of high solids coatings for railroad tank cars

According to the American Association of Railroads, there are currently over 430,000 railroad tank cars in service. The vast majority of these cars are not owned by railroads, but leased by private customers who use them to transport their products. Many of these lessees encounter a similar problem with their tank cars. It has to do with the percent solids of the coatings used to protect them. For a refresher on the percent solids of a coating, check out this post we wrote on 100% solids coatings.

Due to the cylindrical shape of tank cars, and gravity, it’s more difficult to achieve the desired film build on the top of the tank, often leading to an unevenly applied coating. During its service life, this top portion of the car will be prominently exposed to repeated rain and harsh sunlight. Eventually, the stress leads to a problem known as “blooming,” or rusting on the top of the tank car. “Redheads,” as cars with this problem are known in the industry, are a good indication that something went wrong during the coating application process.

How to prevent rusting on the top of a tank car

This problem can be avoided by using coatings with a higher percent solids. With fewer solvents flashing off, the coating dries more quickly and it’s easier to achieve high film builds on the top of the tank. The end result is a coating that’s more evenly distributed over the entire tank car. But that’s not the only benefit of using a higher solid coating.

Coatings that contain higher solids by volume also allow a shop to purchase less material to cover a given square footage. If a typical 60 percent epoxy has a theoretical coverage rate (where no loss occurs during the application) of 190 square feet applied at 5 mils DFT, an 80 percent solids version would have a theoretical coverage rate of 260 square feet applied at 5 mils DFT. The result is 27 percent less product that’s capable of covering the same area.

How to limit VOCs

Higher solids coatings also significantly cut down on the amount of volatile organic compound (VOC) and hazardous air pollutant (HAP) byproducts. Lower levels of evaporating solvents mean fewer VOCs are released into the atmosphere, and into the shop. For large-scale operations VOCs can add up quickly, making cutting back on these substances necessary to avoid fines. Tighter regulation of VOC outputs may increase the importance of alternative choices in the near future.

Some attempt to completely take VOCs out of the equation with water-based coatings. But this approach also has its drawbacks. They take longer to cure, potentially causing backups in the shop. Properly accounted for, this strategy can be a viable solution. But like we’ve talked about before, the best solutions draw on a number of key features.

A balancing act

Ideally, the right product will offer a balance of these key features. It should have relatively high solids by volume for film build, and low VOC output to ensure that the shops where it is applied adhere to environmental standards. It should be able to be applied efficiently and in a timely manner. And of course, it must be a cost-effective solution. Click the link to read more about our railcar coatings, or visit our tank linings page for more on linings.

Filed under: Uncategorized by admin
Comments Off on High solids coatings for railroad tank cars

Choosing the right railcar coatings

There are a lot of options out there when it comes to choosing the best coatings to protect the railcars you own or lease. So how should you know which one to choose?

When it comes to selecting the right product to protect your cars, it’s best to consider your goals for the coating. How long do you expect it to last? How much time do you expect to spend applying it? What sort of abuse do you expect it to withstand? The answers to these questions will provide a good basis for your strategy moving forward.

If you’re expecting a long life cycle for your coating, it goes without saying that a more durable product is in order. But if you know the railcar is brought in every five years for scheduled maintenance, it may not make sense to go with the most durable multi-coat finish when a sufficient, single-coat system could do the job at a lower cost.

Many shop owners worry about long curing times causing a bottleneck in their facilities. Situations like these make single-coat systems attractive. After a sandblast, the railcar can be painted and then moved on down the line, therefore avoiding longer cure times. Epoxy coatings may cure more quickly, but may not be suitable if long-term UV protection is needed.

It is especially important to consider a tank car’s intended use where linings are concerned. The longer handling times associated with baked-on phenolics may be unavoidable if product purity is a concern. Since discoloration, odor or other interactions with the coatings system are unacceptable in the transport of food-grade items or sulfuric acid, a baked-on phenolic will likely be the best bet.

The importance of choosing the correct tank car lining has increased with the prevalence of hydraulic fracturing as an energy extraction method. Since water often accompanies this method as a byproduct, care must be taken to ensure that water, settling at the bottom of the tank, does not corrode and pit the steel. When leasing a tank car, this sort of damage could substantially increase maintenance costs upon returning the car. This is a concern tank car owners have only recently had to consider. There are also significant benefits of high solids coatings for these railroad tank cars.

Choosing the right railcar coating is all about how you expect it to perform. It’s important to consider your expectations for service-life, coating application time and the intended use of the railcar. Once an owner has decided what aspects of performance are most important, then choosing the coating that will provide those benefits becomes that much easier. Visit our railcar coatings page for more information.

Filed under: Uncategorized by admin
Comments Off on High solids coatings for railroad tank cars