So my new laser module produces a lot more smoke, that makes sense since it is much more powerful.  It is possible that I need to up my air assist game, although I did not see significant scorching on the few test cuts that I have done so far.  What is clear from the smell in the garage is that it is time to revisit my air cleaner design.  To start off lets look at what some commercial units achieve and how they are built.  That will be our guide for trying to make a lower cost unit that is good enough for our needs.  

The Glowforge Air Filter is rated at around 350 m^3/h (200 CFM), and uses a 4" hose. It weighs in at around 22 kg ( 48 lb) and stands about 430  mm (17 in) tall and cost about $1,000.  A glowforge is basically a 50w laser, so it is sized much larger than our needs, but it is a good upper bounds.  The filter cartridg is a single monolithic unit that takes up most of the space in the unit and cost around $250.  There are no details on this but presumably it is some combination of a HEPA filter and an activated charcoal filter.

MatterHackers sells a BOFA AD 350 Fume Extractor for $2,500 that is suitable for even larger lasers.  This uses similarly priced filters to Glowforge but they come in two parts with a lower cost $100 pre-filter and a $300 HEPA/Charcoal filter combo unit.  It can generate 223 CFM, weights 77 lb and stands 23in tall.  This is way overkill for our needs, but it is close to a professional grade filter.

There are several lower cost filters available on amazon that are mostly geared towards solder fume extracting, but that may be big enough to get the job done. Example 1, Example 2, Example 3, Example 4.  And there are a few that are geared more for laser cutters as well, like the ones from Omtech and Vervo. These are all a lot less expensive than the semi-pro filters above.  However they are smaller, and the replacement filters are difficult to find and often cost as much as the whole unit.

Finally we have carbon filters and exhaust fans from the indoor growing scene.  These are quite inexpensive, but also lacking in many ways.  For one they don't have an integrated housing, so you have to run the air backwards through the filter if you want to suck up smoke from a hose, or you have to build an enclosure for the filter.  Another issue is that there is little or no pre-filter on these and they are mostly geared towards filtering out orders and not smoke particles so they really should be paired up with a proper HEPA filter.  On the upside they are much better than a low cost soldering iron filter and they could act as a pre-filter for venting air outdoors that has less smell/smoke to it.

There is always the possibility of making your own filter from scratch.  However that is tricky at best.  Getting a fan and fabricating a case is not difficult but trying to come up with quality filters for a reasonable price is a challenge.  It is easy to push the cost up into the price range of a proper unit.