# Exhaust for the shed



## bravo (Apr 23, 2017)

My shed is starting to get pretty warm during the day. So I thought I would make an exhaust fan. This will also help with fumes from welding. 

The metal I used was a piece of metal from the inside of a roll of Steel banding which would have been thrown away, a handful of Pop rivets, some pressed board in the fan from an old space heater. 
	

		
			
		

		
	













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## woodchucker (Apr 23, 2017)

if you are welding, that's not enough volume.. you need to pull more CFM out.


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## bravo (Apr 23, 2017)

It's just to get the hot air out of the shed, but for the occasional indoor tig weld it will be better than no exhaust at all. Like I have been doing it for years. 

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## Rustrp (Apr 23, 2017)

I have a couple of 34" tubaxial fans with 5 HP motors I'm getting ready to list on CL, that will move that warm air, but then you didn't know. 

I like the design but I think it's a little small for the amount of air you want to move. A louver and an open door usually does more than most attic fans, plus you don't have to pay for the convection process.


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## bravo (Apr 23, 2017)

I have a fan that moves tons more air but it sounds like a jet engine spooling up. It's from a server. 

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## woodchucker (Apr 23, 2017)

I have the squirrel cage fans from servers of yesteryear.
I also have a blower for a HVAC that my friend replaced, it has 4 speeds,
And then there are regular fans that can be put in front of a gable vent.
I just don't see that little guy doing nearly enough to remove the heat, or especially remove the dangerous fumes from welding.


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## bravo (Apr 23, 2017)

woochucker said:


> I have the squirrel cage fans from servers of yesteryear.
> I also have a blower for a HVAC that my friend replaced, it has 4 speeds,
> And then there are regular fans that can be put in front of a gable vent.
> I just don't see that little guy doing nearly enough to remove the heat, or especially remove the dangerous fumes from welding.


This is in front of the gable vent. 

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## brino (Apr 23, 2017)

hhhhmmmm....too many negative comments above.
I want to support all efforts to improve our work areas.

I believe that fan will be miles ahead of no fan at all.
...and the price point of the materials can't be beat.

Well Done!
-brino


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## woodchucker (Apr 23, 2017)

yea, but it's not enough volume. Get a bigger fan, that will move more volume.
Get one that fills the gable vent or even bigger.

Do you know the CFM for that little guy? A small bathroom fan, moves 50cfm.   A better unit will move 200cfm., more in line with what you need for a small shed to cool it and get rid of the fumes.  you want air changing to get rid of the heat.


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## woodchucker (Apr 23, 2017)

brino said:


> hhhhmmmm....too many negative comments above.
> I want to support all efforts to improve our work areas.
> 
> I believe that fan will be miles ahead of no fan at all.
> ...


my bad


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## bravo (Apr 23, 2017)

woochucker said:


> yea, but it's not enough volume. Get a bigger fan, that will move more volume.
> Get one that fills the gable vent or even bigger.
> 
> Do you know the CFM for that little guy? A small bathroom fan, moves 50cfm.   A better unit will move 200cfm., more in line with what you need for a small shed to cool it and get rid of the fumes.  you want air changing to get rid of the heat.


The server fan is 255cfm but it's rather loud. 

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## bravo (Apr 23, 2017)

woochucker said:


> yea, but it's not enough volume. Get a bigger fan, that will move more volume.
> Get one that fills the gable vent or even bigger.
> 
> Do you know the CFM for that little guy? A small bathroom fan, moves 50cfm.   A better unit will move 200cfm., more in line with what you need for a small shed to cool it and get rid of the fumes.  you want air changing to get rid of the heat.


After a little research (Google) i found that this fan is 90 to 100 cfm and the shed is 8x10 

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## wawoodman (Apr 23, 2017)

So, an 8x10 shed, 8 feet high (?) plus the peak section: between 600 and 800 cubic feet. Assuming adequate replacement air, that's around 7 minutes to cycle the air. Too slow.

I'll have to side with the naysayers. We're not shooting down the OP; it was a good idea, and good use of on-hand material.

Having said that, it just plain won't do what he wants. There's nothing wrong with pointing that out.

Just my opinion, of course.


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## Joncooey (Apr 23, 2017)

Fan's a good idea.  Got any windows?  Mine doesn't have windows yet. (On the list).  I figure the cross breeze would be a huge improvement.


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## RJSakowski (Apr 23, 2017)

My woodworking shop gets warm in the summer too.  It was formerly a granary and had a window just below the peak on the end wall that opened to a small machine shed.  I mounted an old breeze box fan in the window. I don't recall what the cfm was but would guess that it is north of 1,000 cfm.  Here is one from HD that moves 2,500 cfm for $19.
http://www.homedepot.com/p/Lasko-20-in-3-Speed-Box-Fan-3733/100405665


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## Terrywerm (Apr 24, 2017)

A small fan is better than no fan, but I must agree with many of you that the muffin fan will not do as a good a job as one might hope, especially when welding. On the other hand, industrial metal work settings usually seek 6 to 8 air changes per hour if my memory serves me correctly. So being able to change the air once every seven minutes would give just a touch over 8 air changes per hour. Not too shabby when you look at it that way.


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## jim18655 (Apr 24, 2017)

Add a length of ridge vent and let natural convection help. The welding fumes should rise and go out. You might want to have a door over it to close it in the winter to keep the heat in. Good job on the recycling used materials.


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## Holescreek (Apr 24, 2017)

It's  the welding comment that has everyone concerned I think. Its a matter of health.  If you can smell the fume you are being poisoned.  My welding bench has a louvered wall mount fan I bought from Ventilation Direct that fits between wall studs that draws the fume away from me.    I have one in the paint booth too.  I think they cost around $100 each back when I built the shop.

It's important to mount them where they draw the fume away from you and pull fresh air past your head.


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## bravo (Apr 24, 2017)

No windows, I just leave the door open. 

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## bravo (Apr 24, 2017)

Update 




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## David S (Apr 24, 2017)

Bravo some of the noise could be from the blade passing the guard supports.  Since it is up so high and won't be a danger try and take the grills off and see if that helps.

David


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## bravo (Apr 24, 2017)

David S said:


> Bravo some of the noise could be from the blade passing the guard supports.  Since it is up so high and won't be a danger try and take the grills off and see if that helps.
> 
> David


It's just a loud fan, I knew it would be. I have a little pwm motor controller that I can use so I can turn it up and down as needed. 

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## David S (Apr 24, 2017)

I understand that you say it is a loud fan.  However there are various reasons for the "loudness"  Blade passing frequency is a biggy.

David


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## woodchucker (Apr 24, 2017)

That will help you get rid of the smoke. Turn it down when you just need to remove the heat, to a level that keeps you comfortable.

If you ever come across a squirrel cage fan, they are usually quieter, and move a good amount of air.  Sorry if I came off too hard.  BTW heatalators are a good source of squirrel cages. I picked up one at a garage sale for $5.


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## rwm (Apr 24, 2017)

Here's what I did. It really sucks:

















I used a free blower from a decommissioned HVAC system. It sucks the door on the garage closed! Sucks the air from the hood from one side and ambient air from the other side. I highly recommend this system. If you don't need the duct, all the easier.

Robert


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## woodchucker (Apr 24, 2017)

Hmmm, with all those wires coming out of the motor, that looks like what I have. Mine has 4 speeds. so you can really dial it in, but low is all I really need.  

BTW did you use rock wool behind that sheet rock, it's a real good fire block, also insulates real well.. sound deadner, And not expensive..


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## Rustrp (Apr 25, 2017)

woochucker said:


> Hmmm, with all those wires coming out of the motor, that looks like what I have. Mine has 4 speeds. so you can really dial it in, but low is all I really need.
> 
> BTW did you use rock wool behind that sheet rock, it's a real good fire block, also insulates real well.. sound deadner, And not expensive..



It looks like he went with gyp so he's still good with his fire rating. Noise? Whaaaat, wad, ya say?


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## rwm (Apr 25, 2017)

It's loud on High but I usually run it on Medium. Still moves air well.
Robert


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## RCWorks (Apr 30, 2017)

I don't weld inside, I have a wood floor. But it does get hot in my small outbuilding.
I opted to run with the Pink Panther and insulated the 4 walls and roof.

My A/C unit is rated at 4 times my floor space. Pre insulation it would not cool noticeably. Now it does.

But for those times of fumes(painting) I put 2 of those 19 inch Wal*mart fans in the window and open the door. I may have to point the fans in depending on the wind direction. I get winds that will stop those fans if they are blowing in to it.


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## Ridjobradi (May 3, 2017)

When I replaced the condensing unit on home's AC, I kept the fan assembly. It is now mounted I  the gable of my shop, to help pull air through. I live 2 block from the Gulf of Mexico and the extra air movement helps. 

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