# Microwave Fan for Exhaust?



## Leeguana (Jul 31, 2008)

We had a microwave that died a few years ago, and today I decided to experiment. I pulled out the fan, connected the two wires coming out of it to an old lamp cord, plugged it in, and voila, it works! 

I've been looking for a cheap exhaust fan for my grow cabinet (4'H x 2.5'W x 2'D) and I'm wondering if this just might work. The fan blade is only 4.5" across, but the whole thing must weigh close to 2 pounds. It blows like a mini-jet propeller, and from googling the CFM of microwave fans, it's probably pushing around 200 CFM.

Does anyone have any experience using a microwave fan for their exhaust? From reading the forums, I've got some pretty decent ideas for a DIY odor control filter, but any tips on how to mount the fan would be greatly appreciated (since I'm severely challenged in the area of electronics). Are there any safety issues I should be concerned about? (for example, when I plug it in, I'm afraid to touch any part of the motor, for fear of being electrocuted, lol). Here's a couple pics of the fan (the 3 screws on the back are where it was mounted inside the microwave):


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## King Bud (Jul 31, 2008)

Those kind of fans are not so good for carbon filters, since they are not designed to withstand the air pressure difference. For a small room, it might work.. :confused2: you'll just have to see, really. I'd probably save it for an intake fan.


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## Leeguana (Jul 31, 2008)

King Bud said:
			
		

> Those kind of fans are not so good for carbon filters, since they are not designed to withstand the air pressure difference. For a small room, it might work.. :confused2: you'll just have to see, really. I'd probably save it for an intake fan.


Thanks King.  I just figured since it had a fairly high CFM rating for such a small fan, that it might work.  Guess I didn't really think about them not being designed to withstand air pressure differences.


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## Aurora_Indicas_Dad (Jul 31, 2008)

use a 6 or 8 inch duct booster fan for your carbon filter.it shows one mounted on the dl toker homemade carbin scrubber in the diy section.theyre 30 bucks at home depot,menards or lowes.you just have to get a 3 prong powercord to hook them up.


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## Leeguana (Jul 31, 2008)

Aurora_Indicas_Dad said:
			
		

> use a 6 or 8 inch duct booster fan for your carbon filter.it shows one mounted on the dl toker homemade carbin scrubber in the diy section.theyre 30 bucks at home depot,menards or lowes.you just have to get a 3 prong powercord to hook them up.


Thanks Aurora, I'll check it out.


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## The Hemp Goddess (Aug 1, 2008)

Kludge said:
			
		

> Please unplug that and don't ever do that again.
> 
> The power coming out of your wall is AC (Alternating Current) and that fan probably uses DC (Direct Current) so you might have a bit of a fire hazard there. Heck, it might just be an AC motor but why burn your house down over a $10 fan?



I am just curious why a microwave would have a fan that is DC, since the microwave runs on AC?  Are other household appliances that plug in and use fans also this way?  How can you tell whether the fan is AC or DC?


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## ChatNoir (Aug 1, 2008)

I'd recommend case fans, uses less electricity and causes less noise also comes as cheap as 4$


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## Leeguana (Aug 1, 2008)

Thanks for the info on the whole AC/DC thing Kludge.  I've read a bit on Tesla too, he was a pretty brainy dude.  And thanks for the tip on the case fans ChatNoir, I'll get one after this grow is complete (assuming the house doesn't burn down first ).  It's not too loud though, probably no louder than a basic bathroom fan.

Hopefully it's an AC fan, I just assumed it was since it was inside the microwave.  They've only got about 3 weeks left in flowering before I harvest them. It's a surprisingly powerful little fan.

I ended up not making a carbon filter yet, since the wife said I could use our room air purifier (it's got a carbon filter, a hepa filter, etc.). It at least keeps the smell contained in the spare bedroom where the grow cabinet is located. 

I just took some scrap sheet metal from the bottom of the junked microwave, cut a couple pieces to size (I bolted the two pieces together to make a double layer cause the metal didn't seem very sturdy), drilled holes in the metal, and screwed the fan into it. I was going to cut a round hole in the top of the cab for the exhaust, but since this is a temporary fan, I just attached the fan to the hole on the side/top. There's another hole just like it on the side/bottom. I built this cabinet back in the early 90's and kept my Iguana (Joe) in it, so it already has two vent holes (except they're both on the same side of the unit, and they're rectangular shaped, covered in 1/2" wire mesh).

The temp was reaching 90+ and I was having to leave the door open a bit to keep them cool, but with the fan installed, the temp is now topping out at 80 degrees. 

Note to self: Get a real exhaust/scrubber system, and remodel lizard cage so it's more suitable for growing.


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## IRISH (Aug 10, 2008)

nice diy lee. thats using the 'ol noodle. i've got a small grow cab that i'll soon be using for vegging only, and may borrow this idea, as i have two old microwaves out back. good luck on the grow...


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## Leeguana (Aug 12, 2008)

Thanks Banjo.

It does an awesome job on keeping the temperature down. Only a week or so left . . . just 2 plants, here is a shot of the bigger cola . . .


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