Definition - What does Universal Primer mean?
A universal primer is a general-purpose coating that prepares a surface for a subsequent coating (often a top coat). Without a primer, a coating may not adhere to the surface, thus preventing its protective or aesthetic properties. While most primers are specialized for a certain surface type and subsequent top coat, in certain scenarios it may be cheaper or more convenient to use a universal primer.
Common uses include switching between enamel and acrylic coatings, tannin-bleeding timber and on galvanized iron.
Corrosionpedia explains Universal Primer
While choosing a primer for a particular coating application, one might not know which specific coating will be used, or the primer may be intended for multiple priming jobs on various types of surfaces. In these cases, choosing a universal primer over a primer specifically designed for the job may be a satisfactory solution. Not all coating scenarios require expensive high-performance solutions.
Regardless, universal primers come in a variety of formulations depending on the supplier. A particular formulation may be more important for certain applications. For steel, some universal primers may come with rust inhibitive pigments, while others do not. The solvent compatibility of the universal primer is also important, as top coats such as polyurethanes, acrylics, lacquers and epoxies may contain strong solvents that can break down a primer coat.
- Prepare surfaces for top coats by smoothing the surface and creating a good surface for top coat adherence
- Cover underlying pigments to help change the color of a surface
- Seal the surface, which prevents moisture from seeping into wood materials and causing unappealing tannin bleeding