Shop vac. vs. Dust Collector question (newbie)

[Ryan Sparreboom]

In its simplest form, an air cleaner is a big fan that pulls air through a filter that traps the dust that is floating around in the air. I think that they are an underappreciated component of dust control.

Here's my take on dust collection strategy.

1. The best thing to do is to trap the dust at the source, before it gets into the air. As has been mentioned, due to crappy collection hood designs at the tool end or other factors, this is nearly impossible to do with tools out of the box. So everyone needs a back up plan to take care of the dust that escapes.

2. The best back up plan is to vent the air (and dust) outside. Since you have a garage, opening the doors and placing a fan in another window/vent to draw fresh air in and vent the bad air out is a viable idea. But this isn't always a viable solution, especially if you live in Edmonton and it's wintertime.

3. Lacking a fresh air vent system, an air cleaner is the next best thing. Where air cleaners come up short is that the conventional wisdom is to get an air cleaner with enough CFM to exchange the air in your shop 6-10 times an hour. I went for 25-30 air exchanges per hour. You can bring down the dust concentration in the air much more quickly by increasing the number of times the air gets circulated through the air cleaner. This is cost effective and easy to do -- all you have to do is install another air cleaner. This is especially easier and cheaper than to trying to upgrade your dust collector to a cyclone system.

4. Dust masks, if yours is like this, are pretty much useless, for two reasons. They don't provide a tight fit to your face, so dust can get around the mask, and they don't filter out the tiniest particles which cause the most damage to your lungs. Unless, of course, your dust mask is something like this.

Wilbur, you hit on one of my main problems. It's not bad right now to have my 18' double garage door open when I work in there. But in the winter, forget it! So I should get an Air cleaner with my shop Vac? Or should I get a DC first?

[Wilbur Pan]

Like all of us, I'm sure you're trying to spread out your purchases. So keeping that in mind, here's what I would do.

You're going to need both a dust collector and air cleaners, but you won't need the air cleaners until the weather gets cold enough that you can't vent air to the outside anymore, which I'm estimating in your case will be August 6. So get the dust collector first. The least expensive option is to get a 1.5 HP dust collector with a 1 micron filter bag, and move it from machine to machine as you use them. There are smaller dust collectors, but I think that might be penny wise and pound foolish, as they just won't generate the CFM necessary to effectively collect as much of the fine dust (dust particles that have a diameter of 1 micron diameter) at the tool as possible.

I'm going to guess that your two car garage is about 20' x 20' x 10'. That gives your workshop an air volume of 4000 cubic feet. Like I mentioned before, although conventional wisdom says you should try to exchange the air 6-10 times an hour, I went for 25 exchanges per hour in my shop. The reason for this, without going through all the math, is that at 6 air exchanges per hour it will take about 2.5 hours to collect 99% of the airborne dust, but at 25 air exchanges an hour, it only takes 30 minutes to get to the same point. This is with pretty conservative estimates, and if you want all the gory math details, let me know.

For a shop your size, two air cleaners should do the trick. You can install one, and then install the other one later if you want to spread out your purchases.

My shop is in my basement, and is only 20' x 11' x 8'. I have a 1.5 HP dust collector that I move to each machine as I use it, and an air cleaner. Both are from JDS.

[Peter Quadarella]

So, it sounds like my plan of putting a big whole house window fan in my garage was a good one . I am curently blasting myself with a pretty big airflow, hopefully it is cleaning out the air as well as an air filter.

[David Freed]

A big, cheap box fan, (or 2 or 3) with a good furnace filter(s) will make a big difference for not much money. It may not last as long as a factory made air cleaner, but it is a good alternitive if the cost is a factor.

[Peter Quadarella]

Well, it wasn't very cheap. It's this one:
http://www.amazon.com/Air-King-9166-...2847435&sr=8-2

I got it for about $25 cheaper than that. I thought about putting a filter in front of it, but besides protecting the fan itself, is there any point? Also, lately I've taken to making it blow inwards while my doors are open, unless I'm sanding right in front of it. It's pretty hot right now and the wind cools me off a bit.

[Ken Ganshirt]

So, it sounds like my plan of putting a big whole house window fan in my garage was a good one . I am curently blasting myself with a pretty big airflow, hopefully it is cleaning out the air as well as an air filter.

Keep in mind, of course, that the air quality will be limited to that of the outside air.

...ken...

[Ken Ganshirt]

Well, it wasn't very cheap. It's this one:
http://www.amazon.com/Air-King-9166-...2847435&sr=8-2

I got it for about $25 cheaper than that. I thought about putting a filter in front of it, but besides protecting the fan itself, is there any point? Also, lately I've taken to making it blow inwards while my doors are open, unless I'm sanding right in front of it. It's pretty hot right now and the wind cools me off a bit.

It sounds like you are pushing lots of air around but are you exhausting the air somewhere or just rearranging it inside the shop?

A worthwhile setup would see the big fan in a window or the walk-in door. That would pull the air in the car door and exhaust it out the window or walk-in door. If you aren't using the fan to exhaust the air you aren't doing much of use to protect your lungs.

...ken...

[Peter Quadarella]

That's what I figured. The fan is in my window, and usually I make it exhaust. It's just been about 500 degrees over here so I've needed the breeze so I don't melt.