Surface preparation is one of the most important steps when refinishing wood. Waterlox Original Tung oil finishes are penetrating oil finishes and should therefore be applied to bare wood (does not refer to stain coat(s) if used). If you have brand new – never coated wood surface, a simple sand, vacuum, tack and coat is all that is needed.
If you intend to “screen and recoat” a non-Waterlox product, or apply where it not possible to strip the finish and apply to bare wood, our Waterlox Original Sealer & Semi-Gloss Finish can be used as a primer/tie-coat. It is imperative to identify the previous coating on the surface to know how to proceed.
Waxed surface. Nothing will adhere to wax other than more wax, and wax surfaces are extremely difficult to re-coat. In this case, you will need to strip the surface completely of any wax. We recommend against sanding or abrading the wax from the surface first as this has the potential to spread the wax around even more and not remove it completely.
We recommend stripping the wax from the surface by using water and ammonia, following the directions on the manufacturer’s label for “stripping wax”. If there is a wax build up, the wax may become gummy and needs to be removed by scraping or wiping with rags. Repeat the procedure several times to be sure all wax has been removed. To remove any wax that has penetrated the wood fibers, the surface should be sanded to bare wood.
Tip:- Even though the wax has been removed from the surface, it may still be present in any gaps or spaces between the boards. These are extremely challenging to remedy and may require scraping to remove the wax. If Waterlox or any other coating is applied over these gaps/spaces and the wax is still present, the coating will not dry and will remain soft and cloudy.
- As we mentioned in the beginning of this section, removing wax can be very difficult and great care needs to be taken in doing so thoroughly. In some extreme cases, the wax may not be completely removable and the surface may therefore not be re-coatable.
After the surface has been stripped completely, begin by coating a 2’ x 2’ test area and allow it to dry for 24 – 48 hours. Initially, test for adhesion with your fingernail. It should be difficult to remove the coating if the wax has been properly removed. Also observe the coating that bridges the gaps/spaces between the boards. The film should not be cloudy or soft. Next, we recommend conducting a cross-hatch test to check for adhesion before beginning the entire project.
Surface coating finish (e.g.: oil-modified urethane, water base urethane, etc.). Since a surface finish lies on top of the wood, and will block the penetrating ability of Waterlox Original Tung oil finishes, we recommend sanding down to bare wood before applying Waterlox Original Tung oil finishes. One method of testing for an oil-modified urethane coating is to apply a drop of ammonia to a small, inconspicuous area. Cover the drop with something hollow to prevent the evaporation of the ammonia (e.g.: Dixie® cup, shot glass, etc.) If the film where the ammonia was applied becomes yellow, it is most likely surface finish.
When removing the previous surface finish, the last sand should be done with 100 – 150 grit sandpaper.
Other oil coatings (e.g.: raw non film-forming linseed oil, soya oil, Tung oil, mineral oil, etc.). Our Waterlox Original Tung Oil products are most likely compatible with these types of finishes. One method of testing for an oil coating is to apply a drop of ammonia to a small, inconspicuous area. Cover the drop with something hollow to prevent the evaporation of the ammonia (e.g.: Dixie® cup, shot glass, etc.) The ammonia will not only yellow (will not yellow on mineral oil), but will eventually wrinkle the film if it is an oil coating.
To prepare the surface, we recommend cleaning the surface with mineral spirits (paint thinner) and allowing it to dry. After the surface is dry, a light buff with a maroon pad or a white maintenance pad for larger jobs or 0000 steel wool or 320 grit sandpaper for smaller jobs is sufficient. Wipe down the surface with mineral spirits (paint thinner) a second time. After the surface is prepared, re-coat with the Waterlox Original Tung oil finishing system.
To be sure the surface is ready, we recommend conducting a cross-hatch test to check for adhesion before beginning the entire project.
Shellac. Our Waterlox Original Sealer & Semi-Gloss Finish is compatible with dewaxed shellac. One method of testing for shellac is to apply a drop of alcohol to a small, inconspicuous area. Cover the drop with something hollow to prevent the evaporation of the alcohol (e.g.: Dixie® cup, shot glass, etc.). The drop of alcohol will dissolve the shellac if the finish is shellac.
To prepare the surface, we recommend cleaning the surface with TSP (trisodium phosphate) and water, doing a clear water rinse and allowing it to dry for 24 hours. After the surface is dry, a light buff with a maroon pad or a 3M® white pad for larger jobs or 0000 steel wool or 320 grit sandpaper for smaller jobs is sufficient. After the surface is prepared, re-coat with the Waterlox Original Tung oil finishing system.
To be sure the surface is ready, we recommend conducting a cross-hatch test to check for adhesion before beginning the entire project.
Pre-finished/Aluminum Oxide Finishes. These finishes are primarily found on pre-finished wood floors, and like surface finishes, lay on top of the wood surface. These finishes are normally not formulated to be re-coated and can sometimes contain silicone. Therefore, sanding down to bare wood is normally the only option for re-coating these types of finished surfaces.
Contact a local floor professional who may specialize in refinishing these types of woods. Once the floor is ready for re-coating, we recommend conducting a cross-hatch test to test for adhesion before beginning the entire project.
Review the “Cross-Hatch Test FAQ” for directions on how to complete one.
