Although this vacuum system may seem a bit excessive, I will be exhausting to the outside. The distance that I need to exhaust to is about 20', so I need as much volume and vacuum to maintain the airflow. The blower will be mounted inside my garage and ducted through a vent through the garage roof. The laser will be in the basement adjacent to the garage.
This will definately keep the noise down as well as any dangerous fumes generated.
The vacuum system that I am using was purchased new here in Toronto from a Woodworking / Metal working retail outlet called Busy Bee Tools at a cost of $159 Can. This system was used as a portable dust collector. It has 600 CFM rating at 8" of water which should do the job providing that I don't have too much in the way of losses. It uses a 1 hp motor at 120VAC. The vacuum systme comes with a dust bag and 10' of 4" spiral ducting. I won't be using the dust bag of course.
The total internal volume of my laser base and enclosure is about 16 cu-ft which means that I should be able to exchange the volume of the enclosure every 1.5 sec approx. By closing off the area that are not being used during the cutting operation, I should be able to get some high velocities around the cutting area....well lets hope so anyway.
I have seen this type of blower on other lasers and it really does keep the smell and smoke down quite a bit.
Hope this helps anyone that might be interested in building a DIY laser.
Richard