How to Finish (Sand) Solid Surface
Finishes range from matte and satin to highly polished gloss. Use a random orbit sander and assorted grit sanding discs to finish the solid surface.
The preferred finish for a particular application is the one that is both functional and attractive. The sanding process is a series of steps where the more steps taken the more polished the finish becomes. It is important to realize that the finish is something you have complete control over and that once it is completed, no additional sealers or coatings of any kind are needed.
The solid surface sheets will arrive from some manufacturers sanded to a matte finish while others will arrive somewhat polished. If the sheets have been handled a lot they may arrive with a combination of finishes where some areas may be scuffed or scratched. It does not really matter; the end product will have the finish you decide to produce.
Solid Surface Color and Intended Use: Why does this matter?
For high-use areas, lighter colors are good and a matte finish is the typical finish chosen. Dark colors show use more readily, especially when the finish is highly polished, so these types of colors and finishes are good for lower-use areas.
The Approach to Successful Sanding
One of the fundamental aspects of successfully sanding a surface is to make sure that the sanding scratches from the previous grit are removed after you have sanded the area with the next finer grit.
For example, you start the sanding process with 120 grit and then sand with 180 grit. After you have made two or three passes over the area to be sanded, the 120 grit scratches should not be visible. However, if instead of using 180 grit after the 120 grit you had sanded with the even finer 280 grit, then the 120 grit scratches would still be visible and many additional passes would be needed to remove them. The point is, by correctly sequencing the grits chosen for each successive sanding, you’ll do less work.
The Movements for the Random Orbit Sander
There are two movements that are important: 1) the movement that the random orbit sander makes and 2) the movement you make with the sander.
The pad on the sander, as the name implies, moves in a random orbit pattern, which means the scratches left from the sanding grit are harder to see than they would have been if the scratches had been in a straight line.
The other movement you make with the sander itself. It is from front to back and side to side where the area to be sanded should be about 2’ x 2’. Each pass should overlap the previous pass by 1/3 the diameter of the sanded path. Repeat this pattern over the area two or three times, wipe the area thoroughly to remove any grit, and repeat the process with the next finer grit.
Sanding Disc Grits and Non-woven Pads
The role of sanding grit is to remove material in a way that with each finer grit, the scratch pattern left by the grit is less evident. The less evident the scratches are translates into the level of apparent shine. Or stated differently, if light rays bounce off a surface without being knocked off track by surface imperfections like sanding scratches, then you would see an undistorted reflection that you would refer to as polished mirror reflection.
As the imperfections on the surface become more pronounced, the light ray deflection becomes more pronounced and the reflected image becomes less distinct going from a polished mirror type image to semi-gloss out of focus or blurred image to matte finish where no image is reflected.
Using non-woven pads adds an interesting touch to the desired finish that is hard to describe. If a matte finish is desired then the last sanding grit to use is 280. If you then make another pass with a maroon colored non-woven pad, which is 320 grit, you get a slight additional touch of “richness” that is different than if you had used a sanding disc with 320 grit.
The Sanding Sequence
Use abrasives with 120 grit and 180 grit to remove heavy scratches and return the surface to one similar to the flat finish provided by some manufacturers.
- Matte finish: Use 280 grit and then the maroon non-woven pad
- Satin finish: Use 280 grit, 400 grit, and gray non-woven pad
- Gloss finish: The degree of gloss appearance desired will depend in part on the material color and particulate composition. Use 280 grit, 400 grit, 600 grit and the white non-woven pad for a moderate gloss. Then for a higher gloss also use the 1000 grit and the 2000 grit polishing compound with the white non-abrasive non-woven pad.
- Surface maintenance procedures are dependent on the type of damage and the degree of shine on the finish. Sand out cuts and scratches with 120, 180 grit, and then 280, which will approximate the matte finish of the original piece. Then use the procedures above to match the final finish.
Grit to Micron Conversion: 120-grit (125 micron), 180-grit (82 micron), 280-grit (52 micron), 400-grit (35 micron),600-grit (26 micron), 1000-grit (18 micron).