Maintenance of varnish systems
Maintenance of varnish systems
Epifanes varnishes contain highly effective UV filters and inhibitors. A well applied Epifanes varnish system with sufficient film thickness will keep its high gloss and provide long term protection against UV radiation. Periodic maintenance, however, is necessary on any exterior wood surface, even when coated with Epifanes varnish.
Maintenance is necessary when loss of gloss is noticed. The time frame for maintenance depends on the varnish film thickness and the amount of UV to which the varnish system is exposed. Delaying maintenance in this stage will lead to further deterioration, cracking and eventually lifting of the varnish system.
In order to keep a varnish system in good condition, we recommend applying 2 or more new varnish coats annually, dependent on climate and exposure. Apply additional coats where the varnish system is exposed to higher UV radiation (i.e. flat horizontal surfaces and/or tropical conditions). Wood edges and areas susceptible to mechanical damage will require more varnish coats. A varnish system with insufficient film thickness will appear thin and can offer only limited and temporary protection against UV protection.
After degreasing and sanding, Epifanes Clear Varnish and Epifanes Woodfinish Gloss can be applied over almost all existing one- and two-component varnishes regardless the brand.
After surface preparation, Epifanes Poly-urethane Clear Gloss may be applied over practically all existing two-component Poly-urethane varnish systems and epoxy resin.
Ensure the existing system is dry and free of dirt, grease, salt, dust and other contamination. Remove sharp wood edges by sanding so they can hold more varnish. To avoid the intake of moisture and possible warping, apply 3 or more varnish coats on the backside of the wood. Also make sure sufficient film thickness is applied on overhanging areas where it takes longer for moisture to evaporate.
Judging the condition of varnish systems
1. Varnish system only shows loss of gloss
Varnish system only shows loss of gloss
If the existing varnish system is still intact, well adhered and without cracks, degrease with Epifanes Spraythinner for Paint & Varnish or denaturated alcohol, sand the surface with P320 dry abrasive paper and apply two or more new varnish coats.
2. Varnish system looks poor, shows loss of gloss and light crazing
Varnish system looks poor, shows loss of gloss and light crazing
An existing varnish system that is still well adhered, but shows both loss of gloss and light cracking indicates neglected maintenance. The varnish system can no longer provide sufficient (UV) protection. In this case degrease with Epifanes Spraythinner for Paint & Varnish or denaturated alcohol, sand the surface further down with P220 dry abrasive paper until all crazing and cracking has been sanded off and apply at least 4 new varnish coats.
3. Varnish system in bad condition
Damaged or lifting adhering varnish systems must be removed by coarse sanding or by hot air gun and sharp (!) scraper. Weathered spots may be treated with a cleaning or bleaching product. If either are used, wash the surface thoroughly with fresh water in order to remove any residue. Allow the surface to dry. If needed or desired, stain bare wood with Epifanes Classic Mahogany Stain. Reapply a full new varnish system with sufficient film thickness.
4. Varnish system needing repair
Varnish system needing repair
After degreasing and sanding, smaller spots needing repair may be filled with several coats of varnish. Use Epifanes Classic Mahogany Stain in case of colour differences. When an equal level has been achieved, sand to a smooth surface and apply one or more coats of varnish on the entire surface. Larger repair areas must be sanded back to bare wood (P220) and reapply a full new varnish system with sufficient film thickness.