Dust Collection Woes!

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Cullcutter posted 10-12-2010 03:31 PM 2967 views 1 time favorited 17 replies Add to Favorites Watch
View Cullcutter's profile


31 posts in 2815 days

10-12-2010 03:31 PM

Disclaimer: I am not the brightest bulb in the box.
Disclaimer: I put the ew in New.

So, I read all of these posts about dust collection and health issues, etc.. So, I decided one of my first purchases should be a good dust collector. I don’t want to spend 1k on a cyclone unit, so I was looking at two stages around 600 or so. I am bogged down in H.P., static pressure, CFM, FPM, exhaust standards blast gates, metal v/ plastic (I understand the grounding concept) and so on. Now, I grasp that I should be after 800 CFM plus for fine dust collection. However, I then read that I need a seperator (trash can?) but that it adds 4.5” of static pressure. My shop is 14×22 (ball park 1 car garage) so I will be adding 6.5” static pressure. So, Assuming I lose no pressure through leaks, faultt connections, poor design, running two separate lines (could do one if needed), I need to overcome a minimum of 6.5” of static pressure and a more realistic figure of 11” of static pressure in order to effectively remove fine and chunk. Given my dimensions and static pressure and the airspeed velocity of an unladen swallow in the month of October, I am completely lost. So, do I need to worry about impeller size (12” i am thinking) or should I be concerned purely with CFM and if that is the case, when I read that a review that states 1550 cfm at 9.5” of static pressure, is that stating that it will produce that amount of CFM with that much resistance or does it create that much resistance itself and I infact now need something that goes toe to toe with 20.5” of static pressure (9.5 from dust collector + 11” of static pressure from set up in my shop). Alright, I need a beer and I probably should check on my wife’s (minor) surgery.

Oh yeah, cabinet table saw, router table, jointer, mitre saw and a floor sweep are my current toys, I mean tools. Yeah, Tools.

Someone, anyone, help, please!

Thank you.

-- I started working with wood because of the biscuits.

17 replies so far

View CharlieM1958's profile


16274 posts in 4213 days

#1 posted 10-12-2010 03:52 PM

It all depends on whether or not it’s Thursday and partly cloudy.

Seriously, if you put this much thought into your woodworking projects, it’s no wonder you don’t have any posted. (Okay, that wasn’t really seriously.)

My shop is the same size as yours, and my dust collection system is a Dust Deputy and a shop vac. Maybe that explains why I cough up projects rather than actually having to build them.

-- Charlie M. "Woodworking - patience = firewood"

View 8iowa's profile


1580 posts in 3756 days

#2 posted 10-12-2010 04:01 PM

In a one car garage shop, approximately 300 sq. ft., you’re not likely to have DC runs long enough to worry about static pressure drop. A dust collector must do only two basic things, have enough velocity (3500 ft/min) in the pipes to keep dust particles suspended in the turbulent airstream, and have enough capacity, cu ft/min, in order to take away the dust and chips from your machine as fast as it generates them. My planer is my test.

You’re not going to have two or three people working at the same time so you don’t need high HP, blast gates, and large diameter pipes taking up valuable space in your small shop. The magazines and their advertisers have almost convinced everyone that you gotta have 2 HP with 4” or 6” piping. For the 1000 sq ft or larger shop this may be true, but in only 300 sq. ft. this is overkill.

In my shops, both in Gainesville, and in the U.P. I have a small single stage dust collector with a 1 micron filter bag. I run 2 1/2” hoses to my tools and get along just fine. In fact I’m getting rather tired of people “chiding” me about my clean shop.

-- "Heaven is North of the Bridge"

View Cullcutter's profile


31 posts in 2815 days

#3 posted 10-12-2010 04:26 PM

Biowa, my jointer and my table saw have 4” dust ports, so I guess going with a 4” piping wouldn’t alter the over all by that much would it?

-- I started working with wood because of the biscuits.

View Cullcutter's profile


31 posts in 2815 days

#4 posted 10-12-2010 04:29 PM

I have a needy wife, a dog that thinks he is a princess and neighbors who can’t grasp the concept of righty tighty. Being the only “handy” man around has it’s advantages (food, drinks, etc…) but it does cut into projects being completed. I have a shop (the other side of my 3 car garage) full of 85% finished projects. I think I have ADD.

-- I started working with wood because of the biscuits.

View 8iowa's profile


1580 posts in 3756 days

#5 posted 10-12-2010 07:58 PM

2 1/2” to 4” adaptors are inexpensive and readily available. The trouble with a 4” hose is that on a smaller HP dust collector, the velocity may fall below 3500 fpm, letting dust accumulate in the hoses. The airstream velocity falls according to the square of the difference in diameter. Sorry for getting too technical here….........just keep in mind the fact that the air speed will decrease in a larger pipe or hose much faster than one would think.

Also in a very small shop, a 4” hose is clumsy & easy to trip over, and where can you put the thing to keep it out of the way when not in use.

Below is my dust collector, “tucked” neatly in the corner by the garage door. I actually have two eight foot hoses, which can be connected together if necessary. They stow nicely behing the dust collector. My shop here in Gainesville is in one half of the two car garage. My wife has her quilting machine in the other half. Obviously I need to keep the environment dust free. Thankfully, my dust collector has been keeping my wife happy.


-- "Heaven is North of the Bridge"

View Cullcutter's profile


31 posts in 2815 days

#6 posted 10-13-2010 07:10 PM

All that I am considering are 2 to 3 hp. Smallest has 2 4” ports and one has 3 4” ports. Also, if running 2.5” plastic how do I ground that?

-- I started working with wood because of the biscuits.

View rance's profile


4258 posts in 3155 days

#7 posted 10-13-2010 07:53 PM

There’s never enough time to finish a project, but there’s always time to start another one.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View Manitario's profile (online now)


2630 posts in 2877 days

#8 posted 10-13-2010 08:04 PM

I think it really depends on how much work you’re going to do in the shop. Before I bought my DC, I did a lot of research and was just as confused. I think that it is simpler than we make it out to be; unless woodworking is your profession and you are running really large machines that produce a huge volume of fine sawdust, you don’t need something huge and expensive. My DC is a 1 1/2 HP 1100 CFM General International with a 1 micron canister on top. I have it hooked up to my TS and my mitre saw. It does an adequate job for each, given the difficulties of capturing dust from a mitre saw. So far I’ve used my shop vac for my 2 1/2 port on my router, which works well. I have found no need for a separator; my understanding of a separator is that it captures the large chips well, so that you don’t have to empty the main dust collection bag as often. I don’t think it improves the fine dust collection, which is what we are concerned about for our health anyways.
The only improvement I plan for my DC system is an air purifier to catch the remaining small dust particles that my DC misses.
Basically, I think any DC over 800 CFM, coupled with an air purifier will be more than adequate for your DC needs.

-- Sometimes the creative process requires foul language. -- Charles Neil

View ND2ELK's profile


13495 posts in 3768 days

#9 posted 10-13-2010 08:22 PM

6” for the main lines, 4” and 2 1/2” for the drops with blast gates at each drop, 2 to 2 1/2 hp unit, metal pipe, one or two drops can be open at the same time. Grizzly has some bag units on sale right now. I have a cyclone but my friend did the same thing with a 2 hp bag unit. I did a blog on dust collection in. It might give you some iedas on lay out.

-- Mc Bridge Cabinets, Iowa

View Cullcutter's profile


31 posts in 2815 days

#10 posted 10-14-2010 04:54 AM

Well i mysteriously received a link to a coupon for the 2hp unit from harbor freight. I read several threads about on here and bought it w/ the coupon came out for 150 with taxes. Tested on my router table and it moves some major air. It isn’t industrial but will suffice for my needs. What are blast gates?

-- I started working with wood because of the biscuits.

View HerbC's profile


1754 posts in 2854 days

#11 posted 10-14-2010 06:34 AM

Blast gates are valves in your hard-piped ductwork system. You normally would have one at the end of each duct run where the ductwork attaches to the equipment. You use blast gates to control which equipment is being serviced by the suction of the DC system…


Be Careful!


-- Herb, Florida - Here's why I close most messages with "Be Careful!"

View Moron's profile


5032 posts in 3888 days

#12 posted 10-14-2010 06:40 AM

welcome aboard

dust is your new friend

-- "Good artists borrow, great artists steal”…..Picasso

View brtech's profile


1029 posts in 2917 days

#13 posted 10-14-2010 03:29 PM

Good choice on the HF. Now you need a Wynn filter, and a Thein Baffle. The baffle is optional, but very handy, and inexpensive. The filter is NOT OPTIONAL, and you need the filter on any DC. You really need to get rid of the fine dust down to .5 micron.

There are two ways to connect a DC. One is a 10’ length of 4” flexible hose that you move around from machine to machine. If that works for you, it’s simple and cheap. The only thing you might want is the adapter that allows you to easily disconnect and connect the hose to the various ports on your machines. The downside is you have to maneuver the DC around the shop as you use your tools.

The other way is to install permanent ducts. Most LJs with DCs in this range use 4” S&D pipe. Run a main line with branches for your machines. Use 45 degree elbows, not 90 and Y’s not Ts. When you install duct permanently, you use blast gates right near where the pipe runs to the machine port to turn off all the ports on all the machines except the one you are running. That puts max suction where you need it. As a practical matter, it means you leave all the blast gates closed, and open the one for the machine you are using.

One nice addition to a permanent duct arrangement is a remote control for the DC.

View crank49's profile


4030 posts in 2965 days

#14 posted 10-14-2010 05:32 PM

The HF 2hp collector does a fine job and has plenty of capacity for most small wood shops. It’ll handle a 4” and a 2-1/2” duct being connected and open at the same time just fine. It has a “Y” with two 4” ports on the fan inlet, so I just used an adapter to reduce one side to 2-1/2”.

Adding the baffle on a trash can between the dust source and the fan has the advantage of droping the big chips, screws and chunks into the can and out of the airflow before they get to the fan. I hate the sound of a chunk of wood or a nail or screw going into the fan, and I think these things will eventually damage a fan. The baffle does add to the static pressure load on the system, but reducing the dust going into the bags can potentially reduce the load, so I think it’s a trade off.

You can run the 4” line in PVC, mounted to the ceiling or walls, with drops at multiple machines if you want. Just install a gate (shut-off) at each machine so you only have one open at a time. I have my jointer and table saw connected this way with a total of 20feet of pipe; works great.

My planer only has a 2-1/2” connection so I use the shop vac for this; it needs the extra static pressurs for high velocity flow. Most shop vacs generate over 60” of static, some go up to 120”, so they are the best choice for dust sources that need high pressure and use small pipes. Most portable power tools fall into this category, like routers, sanders, etc. In the case of the planer, I plan to add a “Dust Deputy” inline cyclone to the shop vac to handle the large volume of chips so I don’t have to enpty the vac so often.

I also plan to build or buy an air filter for the shop air instead of spending money on the cartridge for the dust collector. I want the air filtered all the time, and I don’t want to listen to the collector running that much. That’s just my preference, the independent air filter will cost about $200 where the cartridge would be about half that. But I just don’t want the DC running all the time; the filters are much quiter and clean more air more of the time.

View Cullcutter's profile


31 posts in 2815 days

#15 posted 10-14-2010 07:53 PM

I am also after an air filtration system that is a continous as well so let me know what you come up with. Noticed your avatar, so I’ll assume you ride. I now officially know two cyclists who puddle with firewood.

Sounds like a good Idea to add a remote and the gate explanation helps a lot.

-- I started working with wood because of the biscuits.

showing 1 through 15 of 17 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics