Sanding for adhesion purposes is not required between coats of Waterlox®s Tung oil based, penetrating finishes, making them unique.
Most surface finishes such as urethanes require the sanding process to create what’s called a “profile”. A profile is similar to a mountain range microscopically. Failure to sand/abrade between coats of a surface finish can result in delamination of the new coat from the old coat. With Waterlox®s Tung oil based, penetrating finishes, new coats will actually bond with the previous Waterlox® coat(s) and becomes part of it rather than a layer on top of it.
Even on a finely sanded wood surface, there are peaks and valleys as well as spots of hard and soft grain. When you apply the first coat of Waterlox®s Tung oil based, penetrating finishes, it’s like snowfall on the mountains. The snow caps the peaks and begins to fill the valleys. If you sand, you will unseal the caps and there will be less to flow to the valleys when the next coat of finish is applied. This will result in the cap being re-sealed again, and will therefore result in less available finish to flow into the valley. By not sanding, the next coat will flow away from the sealed caps and do more to fill the valleys. After the third or fourth coat, this self-leveling process is complete.1
1This is the most important reason to obtain the recommended spread rate per coat.
ABRASION TECHNIQUES FOR AESTHETIC REASONS FOR FLOORS:
- Heavy debris or applicator fuzz can be removed from the film with 0000 steel wool, 320 grit sandpaper, or a Scotch-Brite® pad (as shown in the Waterlox® application video on our website.)
- Some customers perform a light buffing between the second-to-last and last coat. This is for aesthetic reasons only. Choose new or used maroon pad or a white maintenance pad with a low-rpm buffing machine. For smaller rooms, choose a drywall pole sander or an orbital sander with 320 or finer grit paper.
- Keep in mind if sand or swirl marks are visible before the final coat, a light sand or buff should be performed before proceeding with the final coat as they WILL be visible. To check for sand or swirl marks, wipe with a lint-free cloth wetted with mineral spirits over an area. While still wet it will provide an accurate visualization of what the final coat will look like.
- Waterlox®s Tung oil based, penetrating finishes should never be abraded with a coarser grit than 150.
- NEVER sand a surface that has been stained as this process will change the color.
TIP
Before using a new applicator, be sure that any loose hairs or fibers are removed or cleaned from the applicator by any of the following methods:
- Wrap the applicator with masking or painter’s tape and then remove the tape completely, or
- Put new and unused applicator pads in the dryer, or
- Use a lint roller on the applicator pad until the lint-roller paper does not pick up any further hair or remains sticky.
ABRASION TECHNIQUES FOR AESTHETIC REASONS FOR WOOD PROJECTS (e.g.: tables, furniture, etc.): Follow the instructions “For Floors” as outlined above; however, because these type of projects are smaller in size you may want to perform a light sanding with 220 or higher grit sandpaper or 0000 steel wool. For fine woodworking, many artisans have used 600 – 800 grit sandpaper before the final coat.
