Dust Collector - Wifey says, "Just get it." (Questions)

[Allan Johanson]

Hi T.J.,

For 5" pipe you can use HVAC snaplock pipe (28ga-26ga should be fine) or 5" spiral pipe. I'm using a combo of snaplock and spiral in my shop depending on the application. Snaplock from the Borg (28ga in 30" lengths in my area) and spiral from a local distributor. I went to an HVAC/plumbing supply place and asked them for spiral pipe. They referred me to a local distributor. Spiral is sold in 10' lengths so bring a vehicle that can carry it. Your local distributor might not be interested in cutting it for you.

For fittings I'm using 28ga HVAC pieces from the Borg. Works for me.

Cheers,

Allan

[Bill Pentz]

If you are working in a basement shop, you are exposing not just yourself but everyone close to you to whatever wood dust you make. With this dust lingering for six months or more before it breaks down or dissipates, this exposure becomes 24x7 for you and your family. Most consider me a fanatic, so spend a few seconds and do a Google search on PM 2.5 health risks and see there are about 5,900,000 references that make it clear anyone who tells you to get a 2 or 3-micron cartridge is ignorant.

To deal with this dust three things need to happen.

1. You fix your tools so they do not spray the fine dust all over;
2. You move enough air to capture that fine dust as it is made; and,
3. You get rid of the fine dust by either blowing it away outside of filtering it off.

Fixing the tools requires opening the dust ports, fixing the hoods and in some cases may be impossible because it requires extensive internal tool redesign. My ducting pages share some well tested designs. Sometimes we cannot fix a tool and even a good downdraft table is not enough. These kinds of tools need used outside or replaced.

Moving enough air requires you look up how much air is required at each machine. Most mess up badly confusing “chip collection” airflows with fine dust collection airflows that are roughly twice as high. AAF, one of the top names in commercial dust collection systems that must perform or their customers will fail air quality checks recommends the following airflows.



Once we know how much air we need to move, we can use that value, typically about 800 CFM for our larger tools, to size our ducting. Most end up needing 6" diameter ducting.

We then use a Static Pressure Calculator to compute the approximate static pressure within our shop. Static pressure tells how much pressure a blower must overcome when working. The below value is typical for most small shops that go with a cyclone. You will save only about 1.5" if you go with a dust collector and no cyclone, but as your filters get dirty will go well over this amount of pressure.



The needed airflow and static pressure are then used to size your blower. Because most small shop dust collectors and cyclones are copies of commercial blowers and typically less well made, a good commercial fan table will give you an idea of the maximum expected performance for a small shop blower. Due to poor design and manufacture many small shop blowers move far less air than identically sized commercial blowers. A fan table also tells you what hp and impeller size you need for your blower. A fan table also shows you when you will burn up a motor from trying to move too much air at lower pressures. Many just fake it believing vendor advertised maximum airflows and end up with about half the sized blower they need.



Getting rid of the dust is best done by using a cyclone to separate off the heavy stuff then blow the fine dust away outside. You can also put your dust collector outside, but most require protection from the weather. Makeup air may also need to be provided to avoid carbon monoxide poisoning because these blowers cans suck exhaust fumes backward through their vents. Heating concerns are best addressed with radiant heaters. If you must filter the dust, you need not only a fine enough filter to address the most hazardous dust, but also you need ample filter area to keep your filters from self destructing.

There are tons of details, roughly four hours a day worth for nearly five years incorporated into my web pages.

Good luck and remember that one round in the hospital makes a good fine dust collection cyclone seem pretty cheap.

Bill Pentz

[T.J. Mahaffey]

Here's what UPS said today:

<table border="0" width="100%"><tbody><tr><td nowrap="nowrap">Feb 14, 2006</td> <td nowrap="nowrap">07:44:00 AM</td> <td nowrap="nowrap">HOT SPRINGS AR US</td> <td nowrap="nowrap">Out for delivery</td></tr></tbody></table>

Yay!
Not that I have any ducting to use with it, but it does give me a chance to put it together this weekend.

[Michael Melo]

I'm all for adequate dust collection. I run a very small shop for a living and was considering a cyclone. Frankly at this stage in my business spending $1000+ on a cyclone just is not in the cards so I purchased the same Delta you just ordered. It is used primarly on the planer and jointer (sometmes the drill press and router table) I have dedicated vacuums for the SCMS and Festool equipment I use.

This Delta does not have the power to run a duct system and effectively collect fine dust. My recommendation would be to get a short 6" flex pipe and connect it directly to the machine and the Delta (use a graduating connection from the machine's 4" port to the flex hose.) Moving it from machine to machine. This may sound time consuming but presumably your batching your processes when building things anyways (its all about productivity in my biz.) For me the extra (literally) couple of seconds it takes to move and plug the hose into the machine is perfectly acceptable.

Best of all you'll get excellent dust collection. If you hate changing bags and/or cleaning the filter often pick up a Lee Valley cyclone lid and turn the Delta into a two stage unit but keep the ducting system out of it if you want optimum performance.

M

[Jeffrey Makiel]

To deal with this dust three things need to happen.

1. You fix your tools so they do not spray the fine dust all over;
2. You move enough air to capture that fine dust as it is made; and,
3. You get rid of the fine dust by either blowing it away outside of filtering it off.

Here in lies the problem for home shops: Capturing the dust at its source. Perhaps easier said than done. In fact, it seems impossible to me as a hobbyist.

For example, how do I capture dust effectively on my tablesaw while using a tenoning jig, or raising panels? How about when I’m cutting dados and grooves? For me to do these tasks, my overarm guard, which has dust collection capability, is retracted out of the way and only the lower dust port on the cabinet is functioning. Even when the overarm guard is deployed, I still see plenty of dust on my sweatshirt and on the floor as the dust particles zoom tangentially off the blade looking for any way to escape. The same goes for my radial arm saw which has a large rear hood and a second pickup off the blade guard. The same goes for my edge sander that has an improved shop made hood. And so forth and so on…

Let's look at the other bad things I do with my portable power tools. Even though I try to use a vacuum with my sheet and disc sanders, dust is still thrown everywhere. It gets worse when the sanding pad is wider than the part. Sure I could run my dust collection system, but at 500 to 600 cfm, it simply can't keep up with dust generation into the ambient air by my sander. Perhaps I should buy or build a down draft table? But how will I lift that chest of drawers onto it? And where will the down draft table go? Perhaps I'll just get rid of the tablesaw and put it in its place. Great idea. Now I can reduce dust generation by a factor of two!

Ok, I'm done power sanding, biscuit joining, routing, drilling and whatever, with my portable power tools. Now comes hand sanding, a dreaded task even without the dust factor. I have to admit, I don't duct tape a vacuum hose to my arm. So, once again, dust is in the air. By the way, I want to feel the progress of my sanding effort, so I brush my hand over the surface. Uh oh, shouldn't have done that!

That's it! I'm done for the day. I polluted the air enough. Time to clean up the shop. Uh oh. Now I'm stirring up all that dust up again. You know which dust, the dust from my previous negligent behavior, with a broom. Perhaps I’ll use a good quality HEPA vacuum…but there’s more trouble as I move stuff around to get at the visible chips that I don't want to track in the rest of the house.

I can't win. Is it because of my dust collection system? Perhaps I'm just ignorant. Or perhaps that’s the nature of home woodworking.

I believe that a dust collection system for a home workshop should be assumed to capture only some of the dust, and only capture the "nuisance" dust and none of the fine particulate dust. Stay with me. This is a conservative approach! I don't care if I have a 5 micron filter, 2 micron filter, or 0.5 micron filter. In fact, I don't care if I ducted my dust collector's exhaust to Mars. It just ain't going to capture the dust from all the different things I do while working with wood. And I'd be kidding myself if it did.

The point I'm making is that if you feel the risk of wood dust exposure is that significant from your hobby, buy a good quality passive or positive air respirator that is NIOSH rated for particulate matter, and make sure it fits well. If I described the things I do in my hobby woodshop to an industrial hygienist, I bet I would hear three words: "personal protective equipment" (that is, respirators!). Don’t believe me? Ask any asbestos worker why they wear a respiratory while using portable HEPA filtration systems, HEPA vacuums, glove bags, water spray, and negative air enclosures.

As for me, I have chosen to take the risk and not wear a respirator because of my wanting to be comfortable while doing one of my favorite hobbies. Frankly, I’ve accepted this risk and rationalize it against other risks in my life, both voluntary and involuntary, including driving to work on US Route #1 in New Jersey!

I do have a decent dust collection system. At least that is my position. It is simply a 2hp single stage unit with some minor enhancements including needle felt bags and 6" duct. That's the extent of my engineering even though I once designed HVAC systems as a professional engineer.

Could dust collection only be done with a cyclone? I don't think so. In fact, I bet my single stage system with decent bags produces more cfm at a given static pressure than a cyclone at the same amp draw even with the lower bag half full. But what difference does it make when I don't capture the dust at its source doing all the things we hobbyist woodworkers do. But I must admit that I don't like fussing with the bags when it's cleaning time. But then again, I don't do woodworking for a living. And time is not money.

My recommendation is to not wrap one's self up too tight in technical jargon when putting together a home dust collection system. I do recommend good filtration media, and erring on the side of overkill is better than underkill. I won't (can't) tell you that breathing the air in your home shop is not without some degree of risk. But I will tell you that your dust collection system is not really the proper answer to complete protection of your health should this be your driving concern. It's nice that dust collection equipment for the home hobbyist has gotten better, and so has the general knowledge through forums as this one. But I also wonder if there is over exageration of the true risks. If not, then we may all be fooling ourselves with our super duper dust collection systems. As for me, I just subtracted the three minutes off the end of my life and moved on.

It’s only my opinion. And I’ve certainly been wrong before!

cheers, Jeff
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[Steven Wilson]

Well Jeff, I sort of felt the way you do untill I started spending a lot of time at the doctors office suffering from sinus infections and spending most of my time on antibiotics. There are a number of ways you can improve dust handling at home

1) Buy tools with decent dust collection. I sold my PC sanders and bought Festool mainly for better dust collection.

2) Get a decent shop vac that isn't real noisy. If the vac isn't a screeming banshee then you're more likely to use it with your circular saw, sanders, etc.

3) Buy stationary tools of a more modern design. The dust collection facilities on my Eurocombination machine are light years better than the old style iron that I use to have. It's amazing how much dust can be sucked up when your duct work extends all the way through your tablesaw cabinet and right up to the blade.

4) Use hand tools. I use hand planes and scrapers a lot because they're not only very accurate, quick, and fun but they also don't produce much dust, they produce shavings. Nice curly shavings don't clog up your lungs like sanding does.

5) Use a small downdraft table for handsanding small parts.

6) If you have duct work then you're impellor better be 14" or better or you aren't in the game. A decent DC unit is a pleasure in the shop. It's enjoyable to have the exhaust air cleaner than your house air.

7) Wear a respirator. There are still a few operations that I wear a respirator for but their a lot fewer in number than a few years back.

[Jeffrey Makiel]

Steven,
Your strategy to 'improve' conditions seems like a good one. However, in my mind, the only way to truly 'prevent' problems is with item number 7. At least, that is what my common sense tells me when I look at all the different tasks I do in my home woodshop. And item #7 is probably the most inexpensive item on your list.

As for me, I probably don't have as well of an equipped shop that you have. Most of my machines are old and were purchased when my financial situation, and my back, were better. However, if the risks are as high as adverstised, and the consequences are as grim as suggested by some sources, thus requiring I replace all my tooling as part of a hollistic approach, I'd probably just quit the hobby. All in all, your underlying recommendation about keeping one' self healthy via mimimizing exposure is sound position and something that I simply can't argue against.
cheers, Jeff

[Allan Johanson]

Hi Jeff,

Another reason for trying to improve the air quality in your shop compared to only wearing a respirator is if your shop air will "leak" into the rest of the house (basement shop) or if your shop is in a garage like mine. My asthmatic wife goes in the garage to get to her car or the freezer. In my situation having excellent dust collection at the source is the only way to go.

Her lungs are a great indicator of the air quality. Since installing the cyclone and also using a large shop vac with a HEPA filter for the small tools, she has been in my shop without a respirator with no ill affects. She had problems before the DC upgrades. It's definitely working.

Side note about tablesaw overhead dust pickups: You mentioned yours wasn't really that effective. It's your gear. My cyclone paired with an Excalibur does an excellent job. Not with a tenoning jig though...

Cheers,

Allan

[Julio Navarro]

Whoa!!!!!!

[Jeffrey Makiel]

I have a basement shop, but I'm able to isolate it from the rest of my home with a door equipped with a door sweep. When I'm using a random orbital sander, palm sander or just hand sanding, I usually put a window fan on and open a window at the other end to let fresh air in to augment the dust that doesn't get picked up by the vacuum. This really moves a lot of air and gets rid of dust as well as fumes from finishes and off gassing of manmade materials. It also creates a negative air pressure to prevent dust from leaving the shop when somebody enters or exits the room. This technique has proven to be very effective for me. The only problem with this approach is that it gets cold this time of year and I end up heating the neighborhood. So I only reserve this when my other means are ineffective. Actually, my preferred method of sanding is outside in the backyard. But this is not always practical.

As far as my equipment goes, I don't think my woodworking machines, and my dust collection system, are any better or worse than most. My 2hp single stage dust collector has great air flow capacity because there is no pressure loss from a cyclone that is quite significant. This translates into more cfm from a 2 hp fan with a 12 radial wheel. For a cyclone to overcome this, you would probably need 3hp to 5hp with a 14" wheel to offset the loss. The other positive features are to use 6" rigid duct with nice straight runs, and make sure to not have an elbow near the fan's inlet. It's actually common sense, and one doesn't need to understand Bernoulli's principle to install a system.

Further, I believe that people have been lead to believe that the air quality leaving a 1 micron single stage dust collector is not as good as the air quality leaving a 1 micron filter on a cyclone dust collection system. It like saying which weighs more: one pound of cotton or one pound of nails? The true benefit of a cyclone is that they are easier to keep clean than a single stage bag or canister system because of pre-separation which is one of the reasons why I used cyclone systems in commercial design. However, I have a hobby woodshop, and it takes me quite a while to fill the lower bag that I only fill half way due to its heavy weight and my questionable back. But this is not a system I recommend for a commercial user because of its maintenance demand. And lack of maintenance will lead to lower flow.

But what does this have to do with hand sanding and portable power tools usage anyway? These tasks are often omitted when folks talk about dust collection. One should probably not believe that harmful dust only comes from large stationary machines especially if one is a general hobbyist woodworker like me. Again, this is only an assumption on my part.

Lastly, (before I run out of hot air ) I would like to reiterate my previous point that a hobbyist uses a machine in many different ways to overcome the lack of having dedicated machines that exist in a commercial shop. If you do not have good hood design, or the operation you are doing prevents you from having a good envelope of capture, the efficiency of your dust collector is academic, and the only guaranteed line of defense is a respirator. Once again, my tablesaw is a prime example.

Again, it's only my opinion and it's on the internet. Take it for what it's worth.

cheers, Jeff