Cool thread, I've enjoyed seeing everyone else's solutions and thought I would share mine.
This is a much more intense approach than most people will take, and I respect that. During the pandemic I started getting really serious about circuits and knew I needed to have some sort of extraction. My first version was made of wood, two PC fans, a PWM controller for speed and a HEPA filter in a vertical stack basically, with a large 4" industrial tube as the intake, and that worked great for years! But since then, I have only gotten more serious and now build and mod guitar amps, and I wanted something more professional without paying thousands of dollars.
After a few more iterations, I brought in an engineer friend of mine and we designed and 3D printed the current iteration, so let me present: Mr. Sucky Sucky, V3.
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Let's start with the fan. It's a
140mm Noctua NF-A14 3000RPM server fan. The reason I chose this fan was because of its CFM (which is the cubic feet per minute, the volume of air, in cubic feet, for each minute the fan moves) to noise ratio. You can absolutely get fans with higher CFM: but they are jet-engine, quad-copter loud. And even this fan is not "quiet", but it is best balance I have found so far between ear fatigue and effectiveness.
It is powered by an internal 120VAC to 12VDC power supply that is fused and takes a standard 120VAC IEC input on the back. The power supply connects to a "motor governor" that you can use to change the speed. I wouldn't recommend this particular motor governor. It does not do 5vDC PWM like the Noctua fan needs. I just had it sitting around already.
The filter is a 1" x 6" x 6" HEPA filter with activated carbon bead filtration, and that part is important. It is two parts, a carbon filter into a standard HEPA weave filter. Basically I make these by buying larger HEPA filters and cut them into squares (
something like this). In studying this topic for my home and general use, I have found that carbon bead filtration, which is a carbon filter made up of small chunks of carbon beads enclosed in a mesh honeycomb like structure, is FAR more effective at removing smoke and smell than the cheap carbon-sprayed mesh that you see everywhere.
You will find this type of carbon filter on industrial and welding extractors. Carbon is proven to reduce / remove harmful substances from smoke, BUT with an important caveat: the effectiveness of the carbon INCREASES with the surface area that the filtered air comes in contact with. The carbon beads provide way more surface area than mesh and is much more effective at capturing smoke fumes and smell.
Here is a picture of the "bead" type vs the mesh type.
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V3 has two "modes". For general use I use as pictured above in the "open" mode, which works exceptionally well if you are close to it (within 6 inches or so). However I also printed a shroud which connects to an articulating tube. This bracket slots on and off the front easily with keyed holes. This is really useful for amps, because they're big and I need to get into precise spots. Using the shroud/tube is way more effective in general.
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It also has flexibility when it comes to filter and fan order. The filter and fan mount into this rubberized bracket that allow the order to be swapped. I still haven't decided which order works better, but I currently run it as filter -> fan -> exhaust.
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I could go on and on, because this thing manages to somehow be both over-engineered and in desperate need of better engineering, but it works fantastic for my needs. I have found there is a vast and empty gulf between the cheapo, loud fan + mesh filter Alibaba / Amazon trash, which aren't much more than "better than nothing", and the effective but VERY expensive filters used by professionals.
I would like to make a V4... maybe one day I will sell the complete package to interested parties.
Maybe one day.
I am happy to share the 3D print files for V3. I am sorry if you're reading this in the future and this link is dead.
CHEERS ALL!