Hidden in the fine print of the U90 paint catalogue is the overcoating window. This tells you how many hours you have to apply the next coat before you have to abrade the surface again. Missing this window is a costly mistake.
Even seasoned painters make errors when interpreting the U90 paint catalogue. Avoid these pitfalls:
Mistake 1: Ignoring the Batch Number The catalogue does not print that colours vary slightly by batch. Always ensure the batch number on the tin matches the "Batch Var" tolerance stated in the catalogue's introduction (typically Delta E < 0.5).
Mistake 2: Confusing "Tintable Base" with "Ready Mixed" Some entries in the U90 paint catalogue are "Bases" (B1, B2, B3). B1 can only make pastel colours; B3 is for deep dark colours. Trying to make RAL 9005 (Jet Black) from a B1 base will fail. The catalogue clearly marks this with a "Tint Strength" icon. u90 paint catalogue
Mistake 3: Forgetting the Curing Schedule The physical properties (like chemical resistance) listed in the catalogue are only valid after full cure, which can be 7 days for epoxy systems. The catalogue notes this in the "Cure Time" column.
Before diving into the catalogue, it is essential to understand what U90 is. U90 is a two-component, aliphatic acrylic polyurethane topcoat. It is designed as a finish coat in heavy-duty paint systems, typically applied over epoxy primers or zinc-rich primers. Its primary functions are:
The "U" stands for polyUrethane, and "90" refers to its high solids content and performance rating. The U90 paint catalogue is organized to help users select the right variant based on environmental exposure, desired sheen, and colour stability. Hidden in the fine print of the U90
Despite the digital age, serious specifiers demand a physical U90 paint catalogue.
While the traditional U90 paint catalogue remains vital, U90 has recently launched a mobile app companion. This app allows you to:
The digital catalogue now also includes a "Sustainability Passport" for every product, detailing the VOC content (as low as <50 g/L for water-based U90 lines) and recycled content of the packaging. Mixing ratio (base:curing agent):
In 2022, a major Saudi Aramco contractor was specifying finishes for 12 atmospheric storage tanks. The initial specification called for a standard alkyd paint. The corroding environment required a polyurethane. Using the U90 paint catalogue, the engineer selected:
The project manager noted: "If you follow the U90 paint catalogue’s surface prep and curing tables, you will not fail a coating inspection."
| Primer | Midcoat | Topcoat (U90) | |--------|---------|----------------| | Epoxy Zinc Phosphate | High-build epoxy | U90 | | Inorganic Zinc Silicate | Epoxy MIO | U90 | | 2K Epoxy (e.g., Jotun Jotamastic) | — | U90 |
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