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Dust Collecting - Questions from the Uninformed Newbie

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Forum topic by David Schwarz posted 11-27-2017 05:38 PM 2781 views 0 times favorited 14 replies Add to Favorites Watch
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David Schwarz

101 posts in 421 days


11-27-2017 05:38 PM

Hi Folks,

I’m not saying I haven’t done any homework – I have in fact devoted a couple hours to researching this question. I am however looking for some assistance – here’s what you need to know:

1. My work space is about 300 SF (single-car garage).

2. I would like to have a central dust collection system to fulfill my DC needs (right now I have a single Ridgid ShopVac that I wheel to each tool as needed).

3. Currently, the following would be connected to said DC system: 10” Cabinet Saw, 13” Planer, 6” Jointer, 13” Bandsaw, 10” Radial Saw, and two routing stations (one built in table station and one Pantorouter). I do anticipate adding more tools in the future, with a Drill Press being an immediate need, but bench sander and perhaps a lathe being future acquisitions.

I don’t foresee ever using more than two tools simultaneously, but I don’t want to be moving the DC from place to place – I have the abilities and budget to install a series of ducts tied into a central station.

Now the questions. Perhaps the key one is how big is too big and what’s too small? On the internet, I found two Delta units that are within reasonable travel distance and priced between $400 and $450. One is a 2 HP single bag system (1,500 CFM) and the other is a 3 HP twin column system (2,100 CFM). Both use 220V single-phase motors that I can integrate into my current electrical system.

My thought is to buy something similar to the two systems described above so that I can have an immediate solution to my dust collecting needs. But eventually I would like to fabricate a cyclone collection system building off of what I purchase. With that background, here is the second question: is it possible to purchase a unit that has a 3-phase motor and then use a VFD to regulate the speed (and therein the CFM power)? If so, and considering that my current work space is likely to be as big as it ever will be – what would be the biggest motor/housing I should consider for such a system? Is this a silly idea or something worth considering?

If you’re still here – thanks for reading. I’m eager for this groups feedback as you have helped me tremendously during my Unisaw acquisition and refurbish.

-- I make trees cry.


14 replies so far

View EarlS's profile (online now)

EarlS

1945 posts in 2552 days


#1 posted 11-27-2017 06:23 PM

David – there are a number of DC threads on LJ that talk about the various aspects of dust collection.

My first inclination is that either system you mention would be “big enough”. Just make sure the system is tight and if you run ducts (PVC) to the various pieces of equipment you need to keep the pipe diameter the same size as the dust collection nozzles on the equipment (usually 3” or 4”). That limits the pressure loss when running the DC system. My approach is to have a 4” line with a tee and a blast gate on the line that is connected to the table saw and another blast gate that has a 4” hose that I connect to the router table, planer, jointer, or other power tool when I use it. That limits the amount of duct you have to run as well as limiting the potential for leaks affecting the vacuum.

You mention the 3HP is a twin column system. I’m assuming that means there is a chip collection bag and a dust bag (of filter) above it?

If you can find out what the vacuum rating is that goes with the cfm you should also be able to verify if there is enough vacuum to handle a second stage. Typically, DC systems run 11” WC vacuum. I think the VFD would wind up cost you in vacuum due to the fan laws. A VFD and 3 phase motor would also cost quite a bit as well as requiring quite a bit more complicated wiring to convert from 240V single phase.

You can build a thein baffle to work as a first stage to knock out the chips and larger dust particles and improve the overall efficiency of the Delta DC as a second stage. You could also buy the plastic in/out top that fits on a 30 gallon garbage can and use it as a first stage. Alternatively, you can also buy a cyclone to install in front of the Delta DC.

I’ve rambled on enough. Take a look at the forums and projects on LJ that relate to dust collection and let us know if you have more questions.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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Redoak49

3670 posts in 2192 days


#2 posted 11-27-2017 07:10 PM

You are quoting mfg cfm data and are way over actual performance. There are a number of good sources for real data.

You do not mention what type, size or length of duct will you be using. You need to understand the ducting and associated losses to figure out what you need.

You say you devoted a couple hours to research which is not enough time. I spent days figuring out what I needed and eventually installed. You can read my blogs on my system.

You can do a couple of different things.

1) Read the Pentz website and study a bunch and plan out what you need. This could take some time and IMHO worth the effort.

2) You can take a guess, spend very little time and just buy something and hope it works.

View David Schwarz's profile

David Schwarz

101 posts in 421 days


#3 posted 11-27-2017 07:18 PM

Thanks gentlemen – I will continue to research and incorporate your valuable insight/opinions. I also need to consider total overall size – we have a tiny Mazda 3 for transport of all acquisitions; otherwise must hire someone/something (Dolly, U-Haul or otherwise) to handle transportation. I’m relatively confident the 2 Hp system is Mazda friendly when disassembled. Not so sure though about the 3 HP. BTW, the two systems I’m looking at are the Delta 50-851 (2 HP) and 50-853 (3 HP).

-- I make trees cry.

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Manitario

2689 posts in 3087 days


#4 posted 11-27-2017 07:23 PM

Depends on how clean you want the air in your shop; I’d go with the 3hp unit; for the small price difference it’ll handle adding a cyclone unit better in the future. By the time you add a cyclone and ducting to the 2HP unit, you’re probably only having less than 500CFM at best, whereas the 3hp unit should be able to maintain 700CFM or better with ducting and a cyclone.

you need to keep the pipe diameter the same size as the dust collection nozzles on the equipment (usually 3” or 4”). That limits the pressure loss when running the DC system.
- EarlS

Agreed, this will reduce the pressure loss (air velocity), but the static pressure (friction) from running 4” or 3” duct will kill your CFM. The problem with the air velocity loss is that you can get chips building up in your ducts but really is not a problem if you go will a 3hp unit. The most efficient design would be to use 6” duct up to each machine and then reduce the diameter right at the machine.

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

View BuffaloBrewer's profile

BuffaloBrewer

61 posts in 1022 days


#5 posted 11-27-2017 07:29 PM

An option to consider if you don’t want to get into ductwork right away is the Rockler dustright system. You can move the hose from machine to machine as you need it without moving the dc unit.

View Greg the Cajun Wood Artist's profile

Greg the Cajun Wood Artist

447 posts in 1146 days


#6 posted 11-27-2017 07:40 PM

Dust collection CFM is comparable to clamps in that you can never have too much. Get the largest dust system you can possibly afford and have space to keep it. In the 50+ years I have been woodworking I have never seen a working shop that was entirely too dust-free

-- Wood for projects is like a good Fart..."better when you cut it yourself"

View brtech's profile

brtech

1052 posts in 3126 days


#7 posted 11-27-2017 07:44 PM

I think the first thing you have to decide is whether your aim is to keep your shop looking clean, or is it to avoid having to wear a respirator while you are running your tools? If it’s the former, than the 2HP Delta will do, although a brand new HF “2 HP” with a Wynn filter upgrade will do about the same for less money.

If it’s the latter, neither are probably good enough, although you might be able to mod the 3HP model up to be good enough. Basically, you want 700 CFM actual at the tool. The CFM numbers you have, as RedOak49 says, are inflated a lot, and you are unlikely to see 700 CFM at the tool. Normally, you need 6” main and 4” drops to get that. Normally, you need something like a 15” impeller to get that. Normally, you need at least 3 real HP to get that. Normally, you only have one (not two) blast gates open at a time. Powering on two tools at the same time is usually unsafe. But, as always YMMV.

Please do read the Pentz site. You don’t have to believe everything he says, although no one has ever actually proven him wrong. He has a lot of real data, useful data, on what the problems are, and at least one way to solve them.

Please don’t confuse separation efficiency with filtering efficiency. A separator, like a Thein baffle, or even a good cyclone, does one thing, and only one thing – it avoids having to clean your filter as often. Anything you get out of your airstream before it hits the filter is good, but only because it clogs the filter eventually. and then you have to clean it out You first have to get your air clean enough (either get little visible dust/chips or be able to not wear a respirator), and THEN you can worry about how often you have to clean your filter.

In the end, you can buy or borrow an air quality meter that tells you how well you are doing on clean, or you can get an airflow measuring device and determine if you have >700 CFM at the tool as long as you have an adequate filter. Of course if all you want is a shop that looks clean, and you wear a respirator when you work, then you can do that by eye :)

I don’t know of any hobbyist DCs that use 3 phase. Even the big ClearVue or Oneida that many of us aspire to own is single phase. More airspeed is usually not a problem, although noise can be,

I’ll bet you can get that “3HP” Delta in the Mazda. It’s just how much disassembly and how many trips you will need.

View pintodeluxe's profile

pintodeluxe

5798 posts in 3017 days


#8 posted 11-27-2017 09:57 PM

I would limit my search to 2-stage units with pleated filters. Unless you can place the collector in a closet, the bag filters stir up way too much dust.

Whatever you install in your shop will probably still be there in 3-5 years, so you might as well do it right. I bought a 2hp wall mounted cyclone and it works perfect. My application and tool collection is similar to yours.
I paid $200 for it at an estate sale. It had been installed in two different shops, but never hooked up to power.

I used to drool over those portable Jet and Laguna cyclones, but next to my full-sized Tempest cyclone those look tiny!

2hp minimum, and ideally a 14-15” or bigger impeller.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View becikeja's profile

becikeja

951 posts in 3017 days


#9 posted 11-28-2017 01:10 PM

Don’t over think it. Get the highest CFM you can afford and have space for and move on…. Fact is, you will never eliminate dust in your shop, you will never reach the pinnacle of not having to wear a dust mask under heavy sanding conditions. Accept it and go start making something.

-- Don't outsmart your common sense

View Fred Hargis's profile

Fred Hargis

5177 posts in 2697 days


#10 posted 11-28-2017 05:31 PM

Good stuff above. I’d bet you can get the larger unit in your car (may not be easy, but probably doable) and it would ensure you have enough power for the future. Just make sure you have enough space for it in the shop.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Redoak49's profile

Redoak49

3670 posts in 2192 days


#11 posted 11-28-2017 05:53 PM

Of course one could rent a truck for a couple of hours to get a larger unit home or maybe have a friend with a pickup truck.

View David Schwarz's profile

David Schwarz

101 posts in 421 days


#12 posted 12-02-2017 03:10 PM

Who would of thought that dust collection could be so complicated! After going through all of the replies, I opted for this 3 HP system (Delta Model 50-853):

Also picked up the rolling feed table in the background. The seller kindly delivered these to my front door at no extra charge, which made this a darn good bargain – if you believe that time is money ;-)

-- I make trees cry.

View NoSpace's profile

NoSpace

142 posts in 1444 days


#13 posted 12-02-2017 06:48 PM

I liked brtech’s reply. Keep the problem as a whole in the back of your mind. First thing is a respirator while cutting, after that everything is gravy. I’d be cautious about ever thinking collection is so good at the source that respirator isn’t needed. How do you really test that?

With the unit you purchased, I’d imagine you have so much power the only real concern is whether or not those bags are going to blow fine dust right back into the shop. I use a Dylos laster particle counter so I know when things are safe. Also, it is really cool if you’re going to build a cyclone so you can actually measure efficiency.

View mummykicks's profile

mummykicks

109 posts in 2006 days


#14 posted 12-05-2017 03:40 AM

If you go to my projects and look at the pic of shop upgrades:
Rigid vac & dust deputy.
2” pvc to all the tools.
I switch the connection at the dust deputy for what tool I’m using and have a 16’ hose for connecting to my sander/tracksaw etc.
I have used this set up for a few years and it works great.
I spent ~$100 on the rigid vac.
probably another $200 on dust deputy/fittings/hose/pvc and such. I got the flexible hose from woodcraft along with the fittings and just cut it and slipped it over the pvc and foil tapped it.
I rarely get anything at all in the vac other than really fine dust. I clean the filter on the vac whenever I fill the 5 gal bucket with sawdust.
The only issue I’ve had was with my cutech planer overwhelming the dust deputy and the chips from the planer fill the vac up. I fixed it by running a hose from the planer to an old garbage can through the lid, and then from there to the dust deputy. Now the chips fill the garbage can first.

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