Sunday, August 26, 2012

DIY: Fume Extractor

Inspired by this post I decided to build a fume extractor. I hadn't even thought about it until I saw this on Hack a Day. I have wanted to do this for a while. I had some points to use, which I redeemed on a Samsung 830 SSD, so in the same order I threw in the carbon filters which was the only thing I needed to buy to build it.



Carbon Filters (5 pack)
http://www.amazon.com/gp/product/B005C5HUI8

The rest was parts I had laying around. I started with an old 120MM computer case fan that was removed when I bought new quieter fans.

Dirty 120MM Case Fan
As part of the fan I already had some plastic filter holders that attach to the fan. I washed the fan by simply wiping it with a damp power towel.

Cleaned fan and filter, with filter holder and 3 to 5 pin adapter

The carbon filter is slightly larger and thicker than standard dust filters. So I have to trim two sides of it to fit. I laid the carbon filter on top and used a razor blade to scour the filter. Then used scissors to finish the job. Make sure you have something underneath while you are handling the carbon filter as it leaves little pieces of filter everywhere.

Resizing Carbon Filter
Here is the fan with the part of the filter holder attached.

Fan with filter holder

The carbon filter is much thicker than the standard dust filter so I wasn't able to just put the top of the holder with the plastic nubs it uses. I didn't have a rubber band that wasn't dry so my fiance used a hair tie to solve the problem, which if you know, comes in handy quite often.

The fan is usually powered from your power supply in your case, which in this instance wouldn't work. I had a power supply from an IDE to USB adapter that would be would be perfect for this. Now that I think about it, I could also use it as a benchtop power supply as it has 2A for each, 5v and 12v. The only thing left is that the fan has the motherboard fan connector instead of the 5 pin molex. Good thing I keep all these adapters when you buy a new computer case! I found a 3pin to 5 pin molex adapter, perfect!

Parts to power the fume extractor

At first, during testing, the fan wouldn't power up. Turns out the 2nd ground connection for the 12v rail isn't real, just a rubber hole. I guess they cut corners where they can on cheap power supplies. This turned out to be quite useful. Using a scrapped molex plug, I was able to make a switch by connecting the ground of the fan to the real ground of the power supply.

Power Supply with dummy ground

Soldering molex for power switch

Here it is in action. It is hard to see the actual fumes being drawn. You can almost see it at the tip of the soldering iron.

Fumes being drawn in
So far I am super happy with the way this turned out. See this post (Renesas daughterboard) to see my first PCB being soldered with the fume extractor and PCB holder. I can't be more excited at how well this worked. No more getting headaches on flux fumes. I have tried using a fan before but it just takes heat away from the iron (RadioShack iron at the time). This is just enough airflow to keep the smoke away from your face and remove the smell from the room.

Please let me know in the comments if you end up building one, I would love to hear about it. 

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