We are in the process of acquiring a Trotec Speedy 400 120 Watt C02 laser cutter / engraver and decided we wanted to build our own fume extraction system for a few reasons:
- We could save gobs of cash building our own unit compared to the Atmos System
- We could save gobs of cash by not having to buy $350.00 replacement filters from Trotec
- We didn’t have any more 240 volt breakers available in our box and honestly, who needs 240 volts for a fan that can move 500 cfm.
As shown below, Trotec specifys that you need to be moving at least 500 CFM @ 6 inches of static pressure at the machine port.
The regional sales rep suggested we pick up a Harbor Ffreight 2.0 HP dust collection unit. For the price these units are great -they move a ton of air, are reliable, and cheap. We use a modified version of one of these in our wood shop that uses a .1 micron HEPA canister in conjunction with a custom built cyclonic dust separator. The downside to these units is that they are crazy loud and way more than we actually need for our intended application.
The unit we opted to build is this:
Including the Oenida Dust Deputy (not pictured), this is a six stage fume extraction system.
Using a cigarette we performed our first test without the charcoal canister mounted to the top unit. We could smell traces of cigarette smoke making it through. There simply not enough activated carbon in the MERV 16 filters to catch all of the smoke passing through even though it did reduce it. When coupling the charcoal canister with the unit, zero traces of cigarette smell can be detected.
Our fan’s max rating is at 790 CFM so this is still more than we need. When using this setup in conjunction with a fan speed adjuster we can set it at medium and is very subtle with regards to noise. You can hear air flowing but you can easily talk around it. At a low setting you can barley hear this unit operating. We don’t currently have an air flow meter but I have no concerns about this setup’s ability to meet Trotec’s 500 CFM requirement at a medium setting.
We used a little window seal at the front of each filter. This would ensure that there are no gaps in the front sections and the extra overhang would allow the front face of the box to apply pressure on the filters so it formed a good seal in the rear section.
Oneida Dust Deputy: $189.00
-We have excluded the Oneida Dust Deputy from the core build price because the necessity of this item is dependent upon the application. We are doing a ton of vector cutting in 1/4″ ply and we decided we want to be able to catch any large particulates before the contaminated air reaches our filtration system. These systems work EXCELLENT and should prevent premature clogging of the filter membranes. We use one of these systems with our Festool CT 26 ShopVac and literally never have to change the bag. The fact that this unit does what it was designed to do perfectly and it is over a 10th the cost of a Trotec Fume Extraction system (excluding shipping) – we could not be more pleased!
If you would like to design one of these units for your self we have provided a sketch up file of the build below as well as links to required parts for assembly.
Phresh 701020 Carbon Air Filter: $185.14
-The advantage of a larger fan intake diameter vs a 4″ or 6″ port is that it will operate much more quietly. You have larger fan blades which can move the air at a much lower RPM compared to your smaller vacuum configurations.
½” Baltic Birch Plywood Sheet: $39.00
-You want to use an exterior grade Baltic Birch plywood. The advantages of using a high quality piece of plywood is that you will get a very flat and even board. Since we are building a system that should theoretically be air tight with the exception of the intake and exhaust port, you want everything to be to spec. Using an exterior grade plywood in conjunction with a good sealer (polyurethane coating / epoxy (which we did), will allow you to set this unit outside without it warping.
Sketchup File: Download Here