SURFACE FINISHING
4.1. Planing or Routing the Surface
Inspect the surfaces of the cured epoxy for any imperfections. Should you not be able to sand and polish these out you may require to use a planer or router to remove the required thickness of material over the full face of the table. Using a CNC machine is the easiest method. You can also use a router sled with a flush trim bit to flatten your slab. We recommend only removing one (1) mm to two (2) mm at a time.
4.2. Filling cracks on table
You would likely uncover a few holes and cracks in the wood while flattening your table. These holes and cracks will need to be filled using epoxy. To prevent any unwanted discoloration of the wood when using colored epoxy to fill these cracks and holes, we apply a very thin layer of clear epoxy over the complete surface of the table, and we basically “stain” the whole surface. Some holes and cracks may need to be filled a couple of times, so always check up on these places.
TIP: use a small scale to mix only small batches of epoxy to do your patching. Occasionally we will use clear super glue to fill the very small holes and cracks.
4.3. Start Sanding
As you may know, the router and CNC machine work does not leave a perfectly smooth surface. The next step in the finishing process is therefore sanding. We initially used a belt sander but we found that the belt sander removes too many epoxy materials at once, leaving uneven surfaces. We, therefore, do not use the belt sander any more. We did however discover a better method by using the Festool Rotex sanding machine. We really like the two different sanding settings of the tool. The first is the Rotex setting which delivers very aggressive orbital sanding (not as aggressive as a belt sander). The second is the normal orbital sander setting.
We would typically start sanding our table surface with 80 grit sandpaper on the Festool Rotex to remove all the CNC lines.
4.4 Cutting Table to Size & Edging
Once you fished the first sanding step, it is time to cut your table to size. The table is only slightly larger than intended, therefore cut away as little as possible. No more than five (5) mm would need to be removed. As with all aspects of the project, the quality and precision of the tools you use will drastically affect your final product. The Festool Plunge Saw 75 has always given us excellent results when cutting our tables to their final size.
We prefer to start with one of the longer sides of the table. Keep in mind that this side will be the reference for all other sides. It is therefore crucial that this side is perfectly square in terms of the intended final design. Use a long straightedge to draw a line along the edge of the table. Be sure to add sufficient pressure on the track for your plunge saw to prevent any movement. Use a plunge saw and carefully cut precisely on the line. Visually verify the quality of your newly cut edge. Once you are satisfied, use a large square to draw two perpendicular lines on both of the shorter sides of the table. Cut on these lines and repeat the process for the last side along the length of the table.
The edges are very sharp and impractical, therefore it is standard practice to chamfer the edges. Before you start it is important to prepare the upper and newly cut surfaces by sanding it to three hundred and twenty (320) grit. This ensures that the router itself as well as the tip runs on smooth surfaces to provide consistent results.
You will notice that the router leaves scratch marks in the process, but do not fret. These can be removed by sanding again using three hundred and twenty (320) grit sandpaper. From here onward you can continue sanding to your desired finish.
4.5. Orbital Sanding Machine / Finishing Sander
Not all sanders are made equal. This is a valuable lesson we learned. Invest in the best finishing sander you can afford. This tool can make or break the aesthetics of the final product.
Finishing sanders usually have a larger more stable shaft, improving consistency, and precision and eliminating the swirl marks normal sanders leave on the surface of the table.
We recently invested in the Festool ETS/5 orbital sander. With this sander, we consistently obtain the surface finish we desire.
The Festool ETS 5 can continuously work for long durations of time, providing consistent results. We will often use this sander daily for six (6) to eight (8) hours.
4.6. Wood Surface Finishing
The wood surfaces are finished with specialized oil. This type of oil is again a personal choice. The oil brings the wood to life, highlighting the finest details never noticed during the building process.
At DIY with Greg prefer to use either Rubio Monocoat or Odie’s oil. These different oils require differently sanded surfaces.
4.7. Epoxy Surface Finishing
The surface of the table consists of epoxy and wood. The epoxy can either be finished to a smoky matt or a high gloss transparent appearance. It is up to you or the client. Each finished look has its own unique method of achievement.
Rubio Monocoat is suitable when the wood surface was sanded with one hundred and eighty (180) grit or two hundred and twenty (220) grit sandpaper, depending on the wood species.
When deciding on Odie’s oil sand the wood using up to four hundred (400) grit sandpaper to give you a much smoother finish.
Ask the supplier or manufacturer for the sanding specifications of the wood, specifically for the oil you choose. It is surprising to see the difference when preparing the surface as prescribed.
4.8. Smokey Finish
We at DIY with Greg prefer the smoky finish on our tables. To achieve this finish, you need to do the following.
Use your finishing sander, loaded with eighty (80) grit sandpaper. Gradually change the sandpaper to 100 / 120 / 180 / 220 and then finish at three hundred and twenty (320) or four hundred (400) grit. The final grit sandpaper depends on the oil you will apply to the wood.
For a smoky finis,h we will not polish the epoxy and apply our wood oil on both wood and epoxy surfaces.
From three hundred and twenty (320) grit onwards, sand for about 20 seconds, remove your sander from your surface, use an air hose to clean the underside of your sandpaper and wipe your surface each type.
Repeat this step for the best finish.
TIP: We will stop sanding at 320 grit sandpaper and move to the Festool 320 grit scotch sanding pad that has a softer surface and will give you a better finish.
4.9. High Gloss Transparent Finish
This finish requires a lot of patience. Follow the same sanding process as prescribed above, starting at 80 grit sandpaper with your finishing sander. Move all the way to one thousand five hundred (1500) grit sandpaper, not skipping a single grit number throughout the process. Ensure you cover the full surface of the table, including the sides with each sanding step. Finally, your surface is ready for polishing.
Tip: In order to ensure the best finish, do the following. From six hundred (600) to eight hundred (800) grit sandpaper, sand for about fifteen (15) seconds and stop. The fine dust interferes with the effectiveness of the sandpaper. Use a cloth to clean and wipe the underside of the sandpaper and make sure to clean your table surface. Finally, wipe the table surface off with a clean dry cloth. Repeat this process from here onward with each increasing grit number.
4.10. Epoxy Polishing
Follow this polishing process only on the epoxy, not the wood. Perform this process using a polishing machine with a rotation speed of at least 2000 rpm. We are very satisfied with Festool polish system, Festool polish system provides consistent results, perfect for a high gloss see-through finish. Festool has three (3) different polishing products we can recommend.
Starting polishing with the orange medium sponge pad with the orange Festool Polishing Agent MPA 5010 OR/0,5L 202048then moving to the blue medium to fine sponge pad with the blue Festool Polishing Agent MPA 9010 BL/0,5L 202050. Lastly, move to the white fine sponge pad with the white Festool Polishing Agent MPA 11010 WH/0,5L 202051.
The polishing process is completed by using a lamb’s wool polishing pad at 2000 rpm until the surface is perfectly smooth. Wipe your polished surfaces with a clean dry cloth.
After your polishing has been completed, only apply wood oil to the wood section of your table and not on the epoxy.
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