Exhaust Fans?

T

Taximanny

Joined
Jul 27, 2015
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I have stopped making knives for a bit to get my shop in order.

I work in the basement and it seems as though my dust collection is not sufficient.
I'm having to re paint the whole upstairs because of my knife making in the basement. ( not that it didn't really need it from the start ).

Anyways I believe with the right setup I can continue work in the basement.

I'm going to build a wall separating the basement in two halves.
The window in my basement is roughly 30" wide and 15" tall.

Thinking of getting two high cfm fans and exhausting everything out.
My plan is to really over do it on the air exchange in the room, so nothing can make it upstairs.




Question is who has done this and where have you got the fans... ?


So I'm looking to pull the air from a 15'x10' room.

Thanks, Manny
 
If you have a furnace or HVAC air handler in your basement, make sure you are not creating an unsafe situation.
 
You have to bring air IN before you can exhaust it. Unless you have an air intake, exhausting won't work well.
The furnace advice is very sound. You don't want to suck air back through the furnace.
I recommend using shop vacs with HEPA filters to clean up. Using fans or blowers with filters attached will clean and recirculate the existing room air, and there are commercial HEPA air filter units available at places like Grizzly.
 
My knifeshop is currently in the basement of my house. I've been working down there part time for the past 3 years. I have the 1 hp dust collector fan from Harbor Freight exhausting through a 3" aluminum dryer hose to the exterior of my house. I have intakes at each grinder, buffer, sander, etc., but only one is being drawn from at a time for maximum suction. I also have an intake near the ceiling that gets opened up when I'm done grinding to get the tiny floating particles out of the air. I let the dust collector run for 5-15 minutes after I'm done grinding. I have a big enough gap under my door, so my shop doesn't get too negative and I don't need any makeup air. Everything goes through a Dust Deputy cyclone, but the one I have is too small.

If you want to see a quick video of my setup, I'll post it on my Instagram account tonight @jmosufsen.

Jesse

Sent from my SAMSUNG-SGH-I337 using Tapatalk
 
i think regular house window fans would work fine for you. i use one and it helped the dust from settling everywhere else in the basement. it only works if you have an open window or vent somewhere else in the basement, not in the same area. air will always be pulling into the room/area with the fan, so it wont be able to drift around.
 
JesseOsufsen said:
My knifeshop is currently in the basement of my house. I've been working down there part time for the past 3 years. I have the 1 hp dust collector fan from Harbor Freight exhausting through a 3" aluminum dryer hose to the exterior of my house. I have intakes at each grinder, buffer, sander, etc., but only one is being drawn from at a time for maximum suction. I also have an intake near the ceiling that gets opened up when I'm done grinding to get the tiny floating particles out of the air. I let the dust collector run for 5-15 minutes after I'm done grinding. I have a big enough gap under my door, so my shop doesn't get too negative and I don't need any makeup air. Everything goes through a Dust Deputy cyclone, but the one I have is too small.

If you want to see a quick video of my setup, I'll post it on my Instagram account tonight @jmosufsen.

Jesse

Sent from my SAMSUNG-SGH-I337 using Tapatalk
Click to expand...

I'll look it up..
That would be great
 
I think people overestimate the importance of air intake. Most houses are much less airtight than might be imagined. If you use a fan to blow air into your workspace, you run the risk of creating positive pressure, which will drive dust into the rest of your house. You want negative pressure, and you achieve this by ensuring air is departing faster than it is entering.

I use an inline exhaust fan from Amazon. I open a window to let air in, but the fan will work without a dedicated intake. My furnace is direct vent, and well sealed. I let the fan run for about 1 hour after I stop grinding.
 
Negative pressures and gas furnaces/water tanks are not something you want to mess with. Drawing even a small amount of carbon monoxide down into a workspace will slowly poison people over weeks

I had this experience in a professional kitchen without an adequate return air system.
 
Air intake should be larger than air exhaust. This is called positive pressure. It is very important for many reasons. The right ratio of in - to - out air is called air-balance. It is an industry in its own right. In the very simplest systems, you want the same size blower bringing air in as the one taking it out. If the entry and exit points are on opposite sides of the shop, it will create a path for fine dust to follow and leave the shop. If the windows are all on one side, use a duct to bring the IN air to the far side of the shop, and an exhaust fan directly in a window. Make sure the In and OUT ports are far enough apart that you don't just draw back in the dust
 
The same way a clothes dryer is often permanently vented to the outside through a hole cut in the basement wall, you could cut an intake hole and an exhaust hole in the basement wall, with HVAC ducts connecting the holes to a 5-sided box around the grinder (or other dust-producing tools). I would put the exhaust hole on one wall and the intake hole on the adjacent, 90 degree wall, so that dust coming out of the exhaust hole won't go back into the basement via the intake hole.
 
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