Breathe Easy with a Laser Cutter Air Filter

A laser cutter is a great tool to have in the shop, but like other CNC machines it can make a lousy neighbor. Vaporizing your stock means you end up breathing stuff you might rather not. If you’re going to be around these fumes all day, you’ll want good fume extraction, and you might just consider a DIY fume and particulate filter to polish the exhausted air.

15203365_644939182347358_619032134291602214_nWhile there’s no build log per se, [ZbLab]’s Facebook page has a gallery of photos that show the design and build in enough detail to get the gist. The main element of the filter is 25 kg of activated charcoal to trap the volatile organic compounds in the laser exhaust. The charcoal is packed into an IKEA garbage can around a prefilter made from a canister-style automotive air cleaner – [ZbLab] uses a Filtron filter that crosses to the more commonly available Fram CA3281. Another air cleaner element (Fram CA3333) makes sure no loose charcoal dust is expelled from the filter. The frame is built of birch ply and the plumbing is simple PVC. With a 125mm inlet it looks like this filter can really breathe, and it would easily scale up or down in size according to your needs.

No laser cutter in your shop to justify this filter, you say? Why not build one? Or, if you do any soldering, this downdraft fume extractor is a good way to clear the air.

22 thoughts on “Breathe Easy with a Laser Cutter Air Filter

      1. You can weigh it when you install, and periodically afterwards.

        The equilibrium values of water vapor adsorbed by activated charcoal are well-modelled, and the remainder of the difference between the periodic weigh-ins and the initial weigh-in is a measure of how “full” the charcoal is.

        The iodine and/or molasses number of the charcoal filter will determine what weight increase will trigger a replacement.

  1. Ok, from what is being described here there is a pre-filter and a carbon filter, but no HEPA filter. From what I understand this will remove most of the odor and visible smoke, but the smallest and most harmful particles will still make it through.

  2. We use a custom filtration system that first passes the hot exhaust gasses thru a wet, humidifier element which condenses most of the vapors (we cut a lot of Acrylic). The cooled gasses then pass through an activated charcoal layer, which seems to last a long time. This ‘reduced emissions’ exhaust is then piped to the outside world. There is little noticeable odor at the exterior vent.

      1. We use Bionaire humidifier media – similar products available at big box home improvement outlets in the HVAC department. The media is a mildew resistant wick that is framed, and suspended vertically in our first filter stage. The bottom of the wick remains in water which creates a damp ‘curtain’ that the exhaust gasses pass thru before reaching the charcoal second stage. We added a seal around the wick which prevents bypassing. Seems to work really well without impeding airflow too much. Wick can be washed if necessary, or easily replaced.

  3. Thanks to everyone for sharing their local exhaust and dilution ventilation tips!

    I recommend that people consider doing air monitoring of the space where work is taking place, as well as at the “breathing zone” (imagine a invisible bubble around a person’s head) of whoever is working in the space. Until you have empirical data showing what the potential contaminant(s) are, and at what concentration, it is hard to say what the best course of action is when designing an effective system to control safety hazards.

    Maybe you have an over-engineered (hooray!) or insufficient (nooo!) system, but without the air monitoring, it will be hard to say for sure.

    Good luck, be safe!

  4. The biggest issue I see is that the fan is between the machine and filter. The fumes and soot will destroy the fan motor and bearings. This happened at TechShop and they had to replace the roof exhaust system with one designed for fumes.

  5. Yes, I agree with you on the point that having a laser cutter tool in one’s shop gives it an edge. Honestly, I am getting scared of doing the job myself. In every sector, experiences matter. Hence, I think I am not fit for it. Really I would want to make an appointment with a good expert who will help me to do this job. To avoid any inconvenience in the middle of the job, you should employ a pro or if you are a great experimenter, do this under the direct supervision of the professional.

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