Hello All. So far in our series of product spotlights we’ve looked at the “Super Primer” Devran 201H and the “Workhorse Epoxy” Devran 224V. Maybe it’s time to look a finish coat. When it comes to finish coats, the reigning champion of the urethane
The data sheet for Devthane 379 describes its intended uses as: “For use on properly prepared and primed steel, concrete or steel floors, masonry, drywall, plaster, metal, concrete block, galvanized, aluminum, poured concrete and glazed brick. Ideal for use on exterior or interior structural steel, piping, metal buildings, control cabinetry, conveyors, pumps, storage tank exteriors, motors, machinery, and transportation vehicles. Can also be used in the hard service areas of food processing plants, dairies, schools, restaurants, hospitals, correctional facilities, factories, stadiums, arenas, and amusement parks.”
I’ve sold it for use on everything from storage and water tank exteriors to concrete trucks and floors. 379 is truly a super versatile product.
Okay, so you already know all this from reading the data page. We all know to sell top quality urethanes for use on exterior structures in high UV environments. So let’s dive a bit deeper and perhaps look at some things about DC379 you may not know….
DC379 can be thinned with two different thinners…T-9 and T-17. Know the difference? T-9 is built for spray application – it’s the ‘faster’ of the two thinners. T-17 is a retarding thinner – it slows things down, gives you more ‘open’ time with the product and thus is what you’d want to use if you’re brushing or rolling DC379. Use T-9 for wide open production work with a sprayer. Use T-17 when you’re needing brush/roller application on ornamental iron work, fences, stencilling by hand, etc. Generally you’d use T-9 for clean up since it’s the less expensive of the two.
DC379 has an accelerator available for cooler weather applications. It’s DC070A0000.
Let’s talk a bit about floors. 379 is an excellent option when a shiny gloss finish is what’s wanted. It can be applied over a variety of epoxies. One very popular system is Devran 224V topcoated with Devthane 379. The 224V gives you a thick wear layer and then the 379 provides excellent UV resistance and a very nice looking finish.
We also like it on aircraft hangar floors where a common system is Preprime 167 (to seal the concrete if it’s open/porous), DC224V as a build coat/wear layer, and DC379 as a finish coat. So why do we want to use 379 in an aircraft hangar? Couple of reason: UV resistance – those hangar doors open a hundred feet wide and let in a lot of sunlight to chalk your epoxy, so the 379’s UV resistance stops this. The other reason is aviation hydraulic fluid that tends to penetrate many epoxies – but it has no effect on the 379.
Another popular floor option utilizes the clear finish available in DC379. Simply apply a color coat of DC224V, broadcast vinyl flakes into the wet epoxy and once it’s recoatable, seal the flakes down with the clear 379 for a very attractive and durable finish.
Let’s look briefly at the clear finish. The most common mistake made with clear urethanes is applying them directly over epoxies in UV exposure. This doesn’t work. The reason being the clear urethane is very clear – cling wrap clear – and the UV rays go straight through it and chalk the epoxy almost as if the urethane wasn’t there. In fact, the resulting chalkiness can delaminate the urethane from the epoxy. So if an epoxy/urethane system is being used in high UV exposure, make sure the urethane is an opaque color coat. Of course a clear coat can be applied over an opaque coat of urethane if desired.
When choosing an epoxy undercoat for urethanes, including DC379, be careful to note the recoat window of the epoxy with urethanes. Usually the recoat window with urethanes is much shorter than the recoat window with other epoxies (the recoat window on page 1 of the data sheets is not for urethane topcoats). A very popular epoxy is our Bar-Rust 235, but careful – it only has a 5 day recoat window with DC379 at 77F – even shorter when temperatures are up around 90-100F. Even the “super primer” Devran 201H only has a 5 day recoat window with Devthane 379. Bar-Rust 231 on the other hand offers a 14 day recoat window with DC379 at 77F. Point being, it’s very important to choose the correct epoxy/urethane combination for the project time frame. Usually you can find the recoat time with urethanes on the product data sheet of epoxies under ‘product characteristics’ which is normally on page 3 of our data sheets.
Finally, let’s talk temperatures and humidity. As with most any converted product – the higher the temperature, the faster they cure. But be particularly careful about high humidity and moisture when you’re dealing with urethanes. They tend to blush/haze up if too much moisture is present during their application and curing. So it’s not a good idea to apply them outside late in the day if there is going to be a temperature drop which will allow for dew/condensation to form on them. Now we do offer polyaspartic urethanes such as Devthane 349QC which moisture actually accelerates to a degree – but we’ll discuss them on another product spotlight. In general, for urethanes other than polyaspartics or moisture cured products – try to avoid high humidity and moisture during both application and cure time.
Devthane 379 is MPI approved under MPI #72. In general 379 is a good generic cross over to: PPG’s Pitthane Ultra, Carboline’s Carbothane 134, SWP’s B65 and SWP Acrolon 218 (218 is polyester urethane) and Benjamin Moore’s Corotech V500. I do hope this gives you a bit more insight into why Devthane 379 is such a widely used popular product as well as some tips which will make it easier for you to used. It provides solutions for a wide variety of needs both exterior and interior.
Dan Daniel Hamm
NACE Certified Coatings Inspector #9633
Dedicated to the commercialization and application of High Performance Coatings and Flooring systems for the Industrial, Commercial and Residential markets with over thirty years of experience in the sale and development of durable surfaces.