Silencing an extractor fan

[Chevy cHaze]

Here's a pic of what I'm talking about, I knew I had this uploaded to my albums at one point:

It's carbon scrubber-fan wrapped in extruded pu mat- sonodec- silencer- sonodec- exhaust.
Completely silent when operating.

cheers,
CC

 

[Rox]

I got myself a duct silencer and it cuts down on the noise very well.

A duct silencer will reduce the noise of the air exiting...but will increase the fan noise due to resistance it creates, the OP is trying to reduce fan noise..

A leepy box is what I would recommend

 

[Dropped Cat]

Use gypsum board, aka drywall, not wood, to skin a box
enclosure:

Closed up, ready to mount:

 

[kushedy]

Nice enclosure. Unfortunately I do not have the time, skill or space for something like that.

I have some padded mass loaded vinyl being delivered very shortly. I'm going to give that a go this afternoon. Thanks for all the input.
I will come back with results

 

[Trich_Tyson]

I put a noisy 8" fan into a large Rubbermaid. I line the inside of the Rubbermaid with 2 layers of density foam (that shit that goes under carpets). I then put down a layer of packing peanuts, wrapped my fan in a blanket placed it in, ducted it out, filled the rest up with peanuts. Put the lid on

Absolutely silent. Used insulated ducting. And left plenty of insulation on the exhaust end to muffle wind.

This was in an apartment complex crawl space. Silence was key

 

[kushedy]

Unfortunately there is not enough space to use that big a box. I tested wrapping the fan in foam coated mlv earlier. Due to the fans mounting bracket getting in the way it was a bit of a mess. It did block a lot of the sound but not enough for my liking. I have since stuffed the fan in the box it came in, ducted & then injected in expanding foam. That's as far as I've got so far. More testing ahead

 

[Trich_Tyson]

I splurged on roxul sound proofing insulation - a rock wool product. I use it to block sound at the hollow core door and at the windows. I have 7 fans going at once + a whole house humidifier.. The room is quieter than the fridge from outside the door. Well worth it, and i still have plenty for future projects.

You can stuff the crevices of the box it came in with that stuff, and/or glue it to the exterior faces.
I think the quality of the material will allow you to downsize the box enclosure.

Another option is sound proofing/draft blocking black out curtains - i got em at bed bath and beyond.. they actually work really well, I drape in front of door.. but I'm sure you can find an application that will help.

IMO it's lots of small improvements that will compound to near silence.

 

[iloveweed123]

How did whatever you decided on go?

 

[kushedy]

No idea yet. Boxed & spray foamed yesterday then ran out of time. Should some time spare this afternoon to go to work on it again. I'm considering adding a bit of mlv to the outside of the box & then I will hook it up & see how well/bad it works.
Will update on shenanigans asap

 

[Bobby Boucher]

I thought an 8" was overkill for the space let alone 10".
This is going in a 60cm wide, 130xm long & 150cm tall cupboard.

Your cupboard is ~40 cubic feet. Panasonic whisper comes in 70, 80, 110, and 150 cfm (i think), and seems to be pretty highly regarded in the micro-garden community. Cubic feet x 2 = recommended exhaust fan cfm rating. Any one of these fans should work providing you have sufficient intake. A passive intake should be at least twice the size of your exhaust, otherwise you wont be doing much in terms of cooling your area, and your fan will shit out prematurely under the stress.. All that negative pressure will also pull moisture from the plants, compounded with the aforementioned cooling issue, and your girls will dry out... What does your intake situation look like? Very common to see undersized intakes.

 

[kushedy]

Ok. Somehow, even after all the wrapping & duct tape used some of the expanding foam managed to get into the fan! It looks like it made its way in where the power cord joins the body of the fan. Fortunately it wasn't too bad. After messing around picking out every little bit I tested the fan & it appears to run without any ill effects.

I put a layer of mlv on the outside of the box & then attached my carbon filter & joint to exhaust ducting.
Low levels sounds have been significantly reduced. What hasn't so much in is the high pitch noise the motor on the hyperfan makes.

I'm starting to think that after all of this I may have picked the wrong fan! My old Ruck 6" can fan was noisy, bulky & drew a lot of electricity but produced more of a loud low level sound which I think is easier to muffle, though the muffling process for that fan shape would take up to much space for grow space.
The speed controller, low wattage & large air movement of the hyperfan swung it for me. Now I'm not sure.
I’m actually considering relegating this fan to another small grow room I have that is more insulated where I’m pretty sure the noise will not escape from. That being the case I would be looking at one of the acoustic fans lined in a silencer. Doing a bit of research.
The 2 main contenders available in the UK are the Can iso-max fans or the hyperfan stealth.
I’m going to see if my local hydro shop has these is stock so I can go have a listen to what they have. Obviously I already have concerns as to whether or not the hyperfan stealth casing has adequately muffled the motor noise of that fan.
If anyone following has input on those 2 fans I would appreciate any input.

Hey Trich Tyson I had not thought about sound proofing black out curtains before. I guess there is only so much you can do to sound proof a fan before moving on to sound proofing the entire grow area. I should have thought of that myself really. That is now on the list of things to do.

Hey Bobby Boucher what I had in there before was a 6” ruck fan on a variac connected to a 6” carbon filter. I was using this on the lowest variac setting. This was enough to keep the temps under control for my old 400w hps cooltube setup.
The intakes for the closet are passive. I have a mylar front panel that is attached to the edges of the closet by Velcro. The closet doors are the sliding type so I just leave them open enough for the exhaust ducting to exit & also enough to allow air exchange. At the bottom of the mylar panels I cut out intake ports & meshed them over. Both are probably double the size of the exhaust.
Anytime the temps started to get to high (during summer) I would just open & fold over the bottom corners of the mylar to allow more air in. I don’t think there is an issue air intake wise.

I have since upgraded to 8 x cxb3590 leds. These in my opinion run cooler than a 400w hps but not cooler than a 400w hps in a cooltube.
There was already too much noise for my liking from the closet with the existing build. Now I need more extraction to keep up with the extra heat being generated I also wanted to address the noise issue.

It’s just the case of minimising the noise generated by a grow in a closet. I appreciate that this kind of grow is never going to be silent but I’m sure it can be improved upon.

 

[Chevy cHaze]

If it is of any interest to you, I can recommend PrimaKlima inline fans, they're cheap, very silent out of the box and available in th UK through various EU growshops...Mine has been running for years now and is still going.

 

[kushedy]

Hey Chevy. I had a look at the PrimaKilma website. I couldn't see any db ratings. They look a bit like ruck can fans but thicker in build.
I think what I am looking for probably hasn't been created yet. Small/medium fan, shifts large volume of air & is quite.
I'm thinking I will give either the iso-max or hyperfan stealth ago. If that is better than what I botched together I'll keep it, if not it will go back.
Then I intend to go with Trich Tysons idea of using some sort of noise blanket/curtain. I.e. I'm going to look at insulating the entire cupboard for sound. Some sort of extra thick insulation around it.