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ThatNinjaWeed
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Terpinolene
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Does anyone see a problem with running a 2 1/2 “ diameter exhaust?

this wouldnt be the size of the fan or ducting or anything just the size of a part i need to fit in my box

ive never heard of it so i wanna know..

At most the whole part is like 2” of 2 1/2 “ diameter the rest would be four

 

is there any reason i should just avoid this completely?

 

also if you know.. what kind of sealant is best to patch holes? Silicone?

can i use like asphault sealant (cones in a tube)

 

Thx

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Posted : October 15, 2020 1:02 am
monkeydo
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If I’m reading this correctly, you want to reduce a 4 inch duct to 2.5 inches. If this is the intention it’s going to create some significant back pressure at full speeds. Dropping from 4 to 2.5 you end up with only 40% of flow capacity in the duct. If you go to 2 inch you are working with only 25% capacity. If you don’t need much flow it could work but it’s far from ideal in most applications. 

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Posted : October 15, 2020 3:31 am
ThatNinjaWeed
(@thatninjaweed)
Terpinolene
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@monkeydo

its a small box - do you think the backflow will make it smell?

is it possible it may actually help the situation by require less of the fan? 

or are you sayin the air will actually go backwards back out the fan?

i dont really get it

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Posted : October 15, 2020 5:39 am
Zombie Nation
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Am slightly confused but why does it have to be 2 1/2" from the box...a pic would maybe help 😉

As Monkey says above, you are asking for problems...airflow would be massively restricted and fan would be working overtime

And what hole size do you need to fill ?

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Posted : October 15, 2020 5:50 am
ThatNinjaWeed
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@zn

just because the hole is square and the screws are where they are..

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Posted : October 15, 2020 5:54 am
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Posted by: @thatninjaweed

@zn

just because the hole is square and the screws are where they are..

Is it a box fan or a homemade box around a normal fan ?

Can you not enlarge the 2 1/2" hole to 4 or 5"

 

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Posted : October 15, 2020 5:58 am
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jacks_farm
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thats a great ideal if it's a square 4" fan 

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Posted : October 15, 2020 6:50 am
Zombie Nation
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Posted by: @jacks_farm

thats a great ideal if it's a square 4" fan 

Never seen a square fan Grin

 

 

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Posted : October 15, 2020 6:58 am
jacks_farm
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Posted by: @zn
Posted by: @jacks_farm

thats a great ideal if it's a square 4" fan 

Never seen a square fan Grin

 

 

I stripped a large server room down a few years back and ended up with about 20 240v 4"pc (18w, 12w) fans and they are great (pc fans say there 4" but the fan blades are about 3" across) 

you can use a fan controller to reduce the noise and they slide in a square 1ltr pot so I can use 5"/6" ducting and use it as an extraction fan 

great for a small veg room or a box to dry the bud in, have the ducting going into the flower room so there no oder 

 

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Posted : October 15, 2020 8:01 am
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Posted by: @jacks_farm
Posted by: @zn
Posted by: @jacks_farm

thats a great ideal if it's a square 4" fan 

Never seen a square fan Grin

 

 

I stripped a large server room down a few years back and ended up with about 20 240v 4"pc (18w, 12w) fans and they are great (pc fans say there 4" but the fan blades are about 3" across) 

you can use a fan controller to reduce the noise and they slide in a square 1ltr pot so I can use 5"/6" ducting and use it as an extraction fan 

great for a small veg room or a box to dry the bud in, have the ducting going into the flower room so there no oder 

 

They be round fans in a square housing, lol...not really suitable for moving the volume of air nessesary from a tent/room...I have a 120mm one moving air around in my drying tent

 

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Posted : October 15, 2020 9:11 am
jacks_farm
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@zn 

Thinking about it, they could be 120mm fans, used one in my old small veg cabnet 

with a few t5's 

They seem to do the job, got the idea from the old micro pc case grows

 

 

 

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Posted : October 15, 2020 9:36 am
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