We will be exhausting through the roof with 4" metal duct with a HF Dust Collector. We are concerned about the smell outside from the Rowmark plastic we are engraving. My idea is to install a furnace filter box in-line with a section of the 4" Straight duct that we have access to. We could then open the box and insert either an off-the-shelf carbon furnace filter or a DIY Carbon filter. I would then seal up the door with the metal duct tape and just cut it open when the filter needs to be changed. I'm not looking for "smell free", just enough to keep the neighbors from complaining.
http://www.airclean.co.uk/1825_Duct_...Filter_Box.htm
What does everyone think?
Thanks for the help.