DC Venting outside

[George Yetka]

So I got my clearvue mostly installed just have to finish venting it outside and the drop from the cyclone down into the garage. I have a few questions though.

Can I split the vent into 2-6" sidewall vents? They make nothing but ugly 8" ones and the wife isnt happy. 6" has some nice options though 8" spiral for house ducting is rated for 180 cfm and 6" is rated for 85. Obviously we will have a heck of a lot more velocity than what you run your furnace at.

Should I open a window before running it? at 1500cfm roughly i will change the air in my shop once every 5 minutes.

Others that vent outside in the cold months do you plan around running it? Should I make all my measurements plan all my cuts run it for 30 minutes bundled up and then run the heat after?

[Lee Schierer]

I don't vent my DC outside.

If you are exhausting 1500 cm you need to let air in at that rate. If you don't you will create negative air pressure in your shop which will decrease the efficiency of the dust collection. Also if you have any burner type heaters in your shop you can pull harmful gasses into your shop.

[George Yetka]

I do not have any heat so that isn't a problem

I do sometimes run a propane heater but very rarely

[Brice Rogers]

I have a workshop with two overhead doors. They have rubber seals, but there is enough air leakage that I don't notice the negative pressure when opening or closing the service door. I also have an overhead "whole house fan" which, when running, wants to open the service door.

I run my dust through a thien baffle and the vent the exhaust outside. What little dust that makes it outside, is negligible. I don't notice any build up.

I live in southern California but inland so the winter evening temps are in the 30's and 40's and the summer peak heat exceeds 100 periodically.

Right now I have a single 5" exhaust (dryer) vent. I might benefit from a 6 or 8". That may be a future project.

So, to answer your question with my own opinion, I would think that a Y with a pair of 6" exhausts would probably work fine. Would it be exactly the efficiency of a single 8"? Maybe or maybe not. In theory, two 6" exhausts have a slightly larger cross-sectional area. But a dust collector and exhaust isn't exactly rocket science. You're just trying to get as much dust collected and exhausted that you can.

[Jim Becker]

As long as the dual outlets have at least the same area as the original outflow, you'll be fine.

[Justin Rapp]

You say you don't have heat, but is your shop attached to the same inside space as your home or another building? Any large capacity exhaust, like a DC being vented outside, could cause back flow flu gasses on a water heater, heating system, dryer vent, etc.

[Jim Andrew]

I have 3 overhead doors in my shop, with weatherstrip, but as the doors are on the inside of the building, air naturally is sucked in around the garage doors. I have no problems needing more make up air to compensate for the DC. I do vent outside, except in the coldest or hottest weather. Do try to get as much done while running DC as possible, then turn it off.

[George Yetka]

Thank you guys I picked up a pair of 6" vents and the sheetmetal i need to put together should have it all together by this weekend.
It is a garage space with standard door leekage and i will opt to crack the windows, But before i do ill ramp it up and cheack the weatherstripping on the inner garage door

[phil harold]

Should I open a window before running it? at 1500cfm roughly i will change the air in my shop once every 5 minutes.

The way fluid dynamics work, you will not change all your air in five minutes.
If you can design a fresh air intake in close proximity of the most used tool with the dust collector, you will only have a river of air between the vent and machine
You could make a flapper like on a doggie door to automatically open when you turn on the DC

[Justin Rapp]

The way fluid dynamics work, you will not change all your air in five minutes.
If you can design a fresh air intake in close proximity of the most used tool with the dust collector, you will only have a river of air between the vent and machine
You could make a flapper like on a doggie door to automatically open when you turn on the DC

I think George was referencing the quantity of cubic feet of air in the shop.

[Carl Beckett]

I vent outside. In New England. In the Winter.

I do nothing special. There IS a slight negative pressure in the shop (no gases or other safety concerns for my shop, but should be considered imo). Sometimes I crack a window or door (especially if this is in line with the dust source, to create an airflow path)

It DOES pull the shop temp down if I run for longer periods (noticeable after about 20 mins). My shop is about 480 sq ft. But air is relatively low thermal mass as compared to all the structure, equipment, tool mass that is already warm. So once the DC goes off, the shop comes back to temp quickly.

I am not running it hours at a time.

At times I have considered adding a filter and recirculating. My biggest concern with this would be the times when I dont empty in time and completely fill and clog (and ruin?) the filter.

[Jim Andrew]

When I run my dust barrel over while venting outside, sure makes a mess both on the outside of the shop and the ground outside.

[Bill Jobe]

George, I just bought an 1800 myself. Perhaps you missed my thread about an idea that came to me....that of running ductwork from outside directly to the machine you use most. This would not only reduce heat/cool air loss, but I also think it would increase the effeciency of the 1800.
Imagine most of your make up air passing directly over the piece as the DC pulls it from the opposite side.
In my opinion, an open window or such causes fine dust particals to circulate the shop instead if being removed by the DC.
I have not come up with a concrete plan yet, but I think the idea has merit.
One poster suggested a closable vent near his lathe or whatever, and I think that is a great idea too. I may just do that.
Seems all the research and sweat is burned up on the ductwork to the DC. To my thinking this leaves out half of the system and perhaps many opportunities to improve air quality in the shop.

[Mike Hollingsworth]

I'm going to bet that an unrestricted 6" has more flow than 8" through a filter.
I exhaust outside. Biggest improvement I've ever made.

[George Yetka]

all the work in the attic is done.
duct run to the inlet
vent to outside through 2-6" drier vents. I may end up ripping this all out and building a plenum box with some lining to quiet things down
Drop through the attic is in
Just waiting on a 5' piece of 6" flex before I can kick it on.

Also I took apart my home made bin sensor when i took out my old dc and my 18 month old loved playing with the strobe until she broke it. Ordered a replacement ended up being wrong voltage so now I wait again