Sanding and finishing of parts

To make the surfaces of a print off the J850 glossy, some post-processing work must be done in the form of sanding and polishing

Before and after sanding and polishing

1. Sanding

Wet sanding with different grits (aggressiveness) of sandpaper will be done. We will start with the coarsest (most aggressive) and work towards the least aggressive

  • The lower the grit number, the more material the sandpaper will remove

Depending on the amount of material you will either start with 180-grit or 220-grit sandpaper. The first step is to wet the sandpaper with water

  • If you are sanding one of the dice or something else with a thin outer layer of material/color, you need to be careful not to remove too much material or the dots will disappear, so start with 220-grit in that case

Sand each face that you would like to have a glossy finish on, sanding each side for a few seconds, and potentially the corners.

  • Once done with the first sandpaper, move up to the next least aggressive grit

The order of grits is 180 -> 220 -> 400 -> 600 -> 800 -> 1000 -> 1200 -> 1500 -> 2000 -> 3000

Do not skip any of the grits in the process or the small scratches from the previous grit might not be removed, leaving the end result not glossy

Do not forget to use the 3000 grit sandpaper even though it looks different. It must also be watered before use.

Ensure to rinse off all of the sandpapers that you used afterwards to remove any debris from the sanding process. Lay the sandpaper out to dry

Note that the part surface will not be perfectly glossy by the end of the sanding process

2. Polishing

Begin by turning on the buffer using the power button. Then press the 900 button

The buffing wheel on both sides should begin to rotate

Next we will add some buffing compound to the wheel. To do this, select the blue/purple bar and hold it up to the edge of the wheel as shown. You should do this for 5 to 10 seconds

  • Note that there should not be any color change on the buffing wheel while adding the buffing compound

Next begin to polish your object by applying light pressure initially against the wheel edge with the part. Examine the part frequently as you go to ensure you only remove as much material as you need to

Before polishing

After polishing

When finished with the buffing wheel, press the power button to stop the rotation. Once rotation stops, press the power button again to turn off the machine