During the first cut tests I was able to step back and watch the spark patterns as the machine made some cuts.  A large portion of very fine sparks get blown away at a 90 degree angle from the cutter.  It would not take much to catch a large portion of the sparks (dust). These are most likely formed from the leading edge of the cut. 

The main table is already 1/2" below the extrusion so this helps.  I wanted to makes some guards that would help even more.

Side Dust Guards

I formed some side dust gaurds that fit over the exposed portion of the side extrusions.

I broke the guards down to two per side. They are held in place by some drop-in T-nuts and M6 screws.

The M6 T nut is meant for 2020 extrusion, but works pretty good on the 8020 10 series.

You can pick them up here:

M6 T Nuts

Note that a couple of the above T nuts would not fit my 10 Series.  For some reason they were a little oversized.

 

Front and Rear Dust Guards

I created a some front and rear gaurds that are held in place with magnets for easy removal.

First I had to attach some steel flat bar stock to the front and rear extrusions, as show here.

These could have been one piece, but I had some stock left over from the table slats, so I used those.

Held in place with some drop-in T nuts and M6 screws.

With all the guards in place I get a little over 1-1/2" of barrier to keep the blown plasma dust from escaping.