Sanding between coats is a familiar step for many applicators, yet the reasoning behind it is easy to overlook. Mistakes during preparation or application can cause coatings to underperform or finishes to fall short, even for experienced professionals.
This guide details when sanding is necessary in epoxy systems and its direct impact on your project’s visual and structural quality.
Why Sanding Matters in Epoxy Floor Systems
Improve Adhesion Between Coats
When completing a UV Finish on a Plain Coat System, or in circumstances where you are applying a polyaspartic directly onto epoxy (like a Metallic Marble System or Sparse Broadcast), sanding is required.
There’s very little chemical bonding between cured epoxy and polyaspartic, so sanding helps by creating a mechanical adhesion, which essentially scratches the surface to give the Sparta something to grip to. Applying a light sand ensures the system bonds effectively across the entire floor area.
Prepare Surfaces After the Recoat Window
Each coating has a specific window where it will still chemically bond to the next layer:
Coatings | Window |
|---|---|
3 days | |
24 hours | |
36 hours |
When this window passes, sanding is essential to prepare the surface for the next application. It reopens the surface profile, allowing the next coat to bond with confidence and helping to preserve the stability and longevity of the system.
Sanding for a Showroom Finish
For projects aiming for a true Showroom Finish, sanding plays an important role in the final appearance. A light sand before the final coat removes sharp flake tips and softens the texture. This creates the smooth, gentle wavy look associated with high-end decorative floors and helps the final coat lay down evenly.
Remove Imperfections Between Coats
Even if you are still within the recoat window, minor imperfections can form as the coating cures. Dust, debris, or roller fibres can settle and disrupt the smoothness of the next layer.
Sanding between coats removes these small flaws so the following layer goes down flat and uniform. This step contributes significantly to the final appearance of the floor.
The Key Benefits of Sanding Between Coats
Sanding plays an important role in the performance and presentation of epoxy and polyaspartic floors by:
- Strengthening adhesion between incompatible layers
- Refreshing surfaces after the recoat window has passed
- Improving the visual quality of the finish
- Eliminating minor imperfections between coats for a clean and even surface.
- Understanding when and why to sand helps applicators deliver excellent results on every project
Talk to APC About Your Next Project
For more insights on coating systems, preparation techniques, and application best practices, explore the APC Blog, visit our YouTube Channel, or contact the All Purpose Coatings team for guidance tailored to your next flooring project.
When and Why We Sand Between Coats