insulating to sound proof extract fan question

callies

callies

Active Member
hi people so i just wanting to know about the safety side of ding this

i want to put my extract fan inside a box and tightly pack it with wool or something that will reduce sound
will the motor or electronics over heat and set stuff on fire if i do that
ive read people put the fan inside a box to reduce sound but im not sure if they pack the box with something
also if i dont care about ever moving the extract fan from the box could i connect the ducking then fill the box with expanded foam
i really dont want stuff setting on fire when im out so if prefer to use a fire retardant expanding foam to fill the box i dont care about the extract fan i can always buy a new one once it dies
what are your thoughts
 
Kingrow1

Kingrow1

Well-Known Member
Yes you can but most of the noise is the moving air not the motor so it might not do much, wrap it in a duvet or few pillos to check before attempting more permenant diy :-)
 
Juiceifer

Juiceifer

Well-Known Member
I wouldn't stuff it tight but I've heard of plenty of people who bix it and add insulation. all the air movement through the motor keeps it all cool.... box it insulate it. suspend the box with bungees to eliminate structural vibration (as I sit hear listening to the hum of my fan in the attic that's sitting on the beams) and add insulated ducting.... sound is just vibrations
 
callies

callies

Active Member
Kingrow1 said:
Yes you can but most of the noise is the moving air not the motor so it might not do much, wrap it in a duvet or few pillos to check before attempting more permenant diy :-)
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i was in the middle of a prototype just a cardboard box and some old blanket for testing reasons not the items ill really use . from my tests so far its reduced it by about 25% so i am hoping once i add insulated ducking ill be another decent reduction
ill leave it in the most janky set up for a few hours and test to see if its gotten hot before buying any materials.
i was thinking wooden box but maybe a plastic tote would be better if i fill it with expanding foam idk maybe it be less heavy but then not sure if the plastic walls will make it echo even with foam
 
callies

callies

Active Member
Juiceifer said:
I wouldn't stuff it tight but I've heard of plenty of people who bix it and add insulation. all the air movement through the motor keeps it all cool.... box it insulate it. suspend the box with bungees to eliminate structural vibration (as I sit hear listening to the hum of my fan in the attic that's sitting on the beams) and add insulated ducting.... sound is just vibrations
Click to expand...
pretty much that is what ive read . i haven't read anyone use expanding foam what i do want to use
 
Juiceifer

Juiceifer

Well-Known Member
If you search it people do the same thing all the time I'm thinking you'll be good as for the wood vs plastic wood has better sound dampening quality but with enough or the right insulation could be null
 
Juiceifer

Juiceifer

Well-Known Member
callies said:
pretty much that is what ive read . i haven't read anyone use expanding foam what i do want to use
Click to expand...
I wouldn't want my fan sealed in the foam if I wanted to remove or maintain it so what I would do is have your fan box spray some foam in the bottom put a smaller box (that your fan still fits in) in the box and spray around the edges let foam cure cut off excess around top. make a lid
 
callies

callies

Active Member
Juiceifer said:
If you search it people do the same thing all the time I'm thinking you'll be good as for the wood vs plastic wood has better sound dampening quality but with enough or the right insulation could be null
Click to expand...
this is my searching ground for this sort of information and i did expect wood to be the better sound dampening product
 
callies

callies

Active Member
Juiceifer said:
I wouldn't want my fan sealed in the foam if I wanted to remove or maintain it so what I would do is have your fan box spray some foam in the bottom put a smaller box (that your fan still fits in) in the box and spray around the edges let foam cure cut off excess around top. make a lid
Click to expand...
i see no reason to maintain the fan if i use dust filters once the bearings go i wouldn't try fix it after my only concern would be if the foam leaked inside the fan somehow or the foam crushing the ducting
box with in a box is a good idea but i think the end product might be huge im thinking that could be a winning idea though
 
Juiceifer

Juiceifer

Well-Known Member
callies said:
this is my searching ground for this sort of information and i did expect wood to be the better sound dampening product
Click to expand...
And if your set on using the spray foam I dont think it would adhere to the plastic (then you have a foam mould worst case scenario haha)
 
Juiceifer

Juiceifer

Well-Known Member
callies said:
i see no reason to maintain the fan if i use dust filters once the bearings go i wouldn't try fix it after my only concern would be if the foam leaked inside the fan somehow or the foam crushing the ducting
box with in a box is a good idea but i think the end product might be huge im thinking that could be a winning idea though
Click to expand...
The box on the inside is just to form the foam while it cures like you would concrete if it can be removed thats what I'd do so maybe the factory box covered in saran wrap and build the quiet box with an extra inch or so inside diameter for foam expansion
 
callies

callies

Active Member
Juiceifer said:
And if your set on using the spray foam I dont think it would adhere to the plastic (then you have a foam mould worst case scenario haha)
Click to expand...
i didnt think of that and now that i am thinking of it i so bet i would of ending up with a big foam block if i use the plastic tote.ill go with wood
as long as i know the thing wont over heat and set anything on fire im happy to try a few prototype. i have 5 cheap old extract fans to play around with before making my final product and use my good fan and ducting
 
Kingrow1

Kingrow1

Well-Known Member
callies said:
i was in the middle of a prototype just a cardboard box and some old blanket for testing reasons not the items ill really use . from my tests so far its reduced it by about 25% so i am hoping once i add insulated ducking ill be another decent reduction
ill leave it in the most janky set up for a few hours and test to see if its gotten hot before buying any materials.
i was thinking wooden box but maybe a plastic tote would be better if i fill it with expanding foam idk maybe it be less heavy but then not sure if the plastic walls will make it echo even with foam
Click to expand...
Some duct noise data somewhere talks of exhausting into a large box which has an even larger diameter of the intake to the box and then through some futher baffled system.

I however have no idea how to stop air noise but simply insulating a motor or in your case the fan reduce it.

I saw advice to buy an oversized fan then run that slower on a variac - this works to reduce both motor and fan noise by a bit.

:-)
 
callies

callies

Active Member
Kingrow1 said:
Some duct noise data somewhere talks of exhausting into a large box which has an even larger diameter of the intake to the box and then through some futher baffled system.

I however have no idea how to stop air noise but simply insulating a motor or in your case the fan reduce it.

I saw advice to buy an oversized fan then run that slower on a variac - this works to reduce both motor and fan noise by a bit.

:-)
Click to expand...
i tried that for the 1st fan i got years ago but i was running the fan off a cheap speed controller and doing that melted one of my timers and put too much resistance in my electrical wiring. i was going to buy a variac to control the speed correctly but i wasn't willing to spend $500 ish at the time. a good variac in aus is not cheap. i will never use a cheap fan speed controller again and i wont buy a variac. i feel safer running my fans full speed and insulate instead
 
callies

callies

Active Member
TintEastwood said:
Acoustic foam might be part of a solution.

https://www.amazon.com/acoustic-soundproofing-insulation-soundproof-dampening/dp/B076JNCQ39/ref=mp_s_a_1_8?adgrpid=56343217579&hvadid=274901347615&hvdev=m&hvlocphy=9032551&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=11893404520411838569&hvtargid=kwd-488637904272&keywords=acoustic+foam&qid=1551672295&s=gateway&sr=8-8&tag=hydsma-20
Click to expand...
i was going to use that to sound dampen my grow room but its not fire retardant so i decided agents buying that stuff. thanks for the suggestion though
 
rob333

rob333

Well-Known Member
callies said:
hi people so i just wanting to know about the safety side of ding this

i want to put my extract fan inside a box and tightly pack it with wool or something that will reduce sound
will the motor or electronics over heat and set stuff on fire if i do that
ive read people put the fan inside a box to reduce sound but im not sure if they pack the box with something
also if i dont care about ever moving the extract fan from the box could i connect the ducking then fill the box with expanded foam
i really dont want stuff setting on fire when im out so if prefer to use a fire retardant expanding foam to fill the box i dont care about the extract fan i can always buy a new one once it dies
what are your thoughts
Click to expand...
inlines i use dont make noise
 
KrazyG

KrazyG

Well-Known Member
I have insulated both ends of my inline fan, the fan itself is not noisey. Majority of the noise is like @Kingrow1 said is wind noise.
I used a 25lt buckets packed with rockwool and it worked very effectively, that's when I realised the fan itself is already quiet.
shareFile(21).jpeg
One before and after the fan dropped my output noise to 17db.
 
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