I have now tried both of the small Harbor Freight dust collectors:
Although the pictures look similar, and the specs are close in terms of CFM and amperage (6.8 vs 7), the clue is that the beige one weighs twice as much and costs slightly more (unless you buy it at 25% off today, like I did):
- 94029 on the left, 31810 on the right
I have been using the little red one successfully but I wanted to see if the bigger one was quieter. It is a
lot quieter. In the same configuration (both hooked to the 2.x laser by 4" flex duct and venting out a nearby window)
the little red one measured 82dB at about 6' away and the big one was only 73dB. That's about half as loud. The big one is also much smoother sounding and more pleasant to listen to.
Despite the optimistic 1/3rd higher CFM of the smaller unit, there is noticeably more suction at the front vents of the laser with the larger DC.
About the only reason I would recommend the red unit to anyone is portability: At 20lbs it it much easier to carry around (even one handed). If I had to schlep it all over a job site I'd be tempted to put up with the noise.
(note for those arriving via Google: I'm only sucking air (and smoke) with these: I have not compared them at their intended purpose of collecting sawdust!)