Bill Pentz vs Phil Thien

[phil harold]

Has anyone compared these two systems with actual figures?
It seems that Phil's design is good and inexpensive, but how does it compare to a cyclone of the same horsepower/cfm.
Is a cyclone going to seperate the same size particles as Phil's seperator or is it better/worse (take the filters out of the equation)

Just would like to know which path to venture
So I need more info

Thanks

[Jim O'Dell]

I don't have a definitive 'I've tried it, measured it, and this is what I determined' answer for you. But, I see Phil Thein's unit as a highly efficient separator of the bigger objects. Bill Pentz's design, as well as other true cyclones, use the shape of the cyclone (the tapered section) to separate most of the fine low to maybe even sub micron size particles. If you have a dust collector, Phil's design will save some wear tear and cleaning of the filters, but I don't see it capturing the really small stuff that is more harmful to breath. Just my humble opinion. Jim.

[Jason Beam]

Apples to Oranges.

Bill advocates a system that will protect your lungs.

Phil advocates a system that will keep your filters from clogging so fast.

That they are sometimes compared is nearly almost always a cost comparison.

[glenn bradley]

Jason took the words out of my mouth. Different animals.

[Greg Peterson]

How and what the DC unit separates is less relevent than how effective the filter is.

A cyclone system is stationary and serves multiple machines. A single stage system is usually used to serve one machine at a time.

With the proper filter or bag the DC system (cyclone or single stage) will not pollute the workshop with harmful fines.

Even a 5 HP cyclone DC system will fail to serve its purpose if effective dust collection isn't practice at every step of the process. Capturing the fines in the first place is the critical element. What the DC unit does with the chips and dust afterwards is relatively insignificant.

[phil harold]

With the proper filter or bag the DC system (cyclone or single stage) will not pollute the workshop with harmful fines.

Exactly

So the question still remains is "How much DC unit separates and how much it sends to the filters", numbers please.

It is not apples to oranges, they are both seperators one looking alot easier to build than the other

If I have a 2hp blower and fan which system do I attach it to

I want to see actual numbers
Does cfm change with them?

[Greg Peterson]

What size particles drop out into the bin versus get trapped in the filter?

Not sure if the measurement you are requesting is feasible or relevent. Perhaps if you are operating a production shop this could be a matter requiring consideration.

As a hobbyist I don't worry about it. So long as the fines don't get captured in my lungs I don't really care where they end up.

CFM is a function of impellor, HP and ductwork. 2 HP is low for a cyclone system. What type of fan you have will also influence the ultimate design. Is it a squirrel cage, impellor or blade type fan?

You might search on Greg McAllister and Phil Thien for some great ideas on DC designs.

[Alan Schwabacher]

I think Phil Thien's baffle increases the effectiveness of a DC so that much less stuff reaches the filters, to the extent that it is quite impressive. An ordinary DC without a baffle does OK when it's empty, but quickly loses capture effectiveness as it reaches 1/3 to 1/2 full. With a baffle it remains effective until nearly full, and possibly is more effective from the start.

I don't think measurements have been made that compare this to a Pentz type cyclone (which I imagine is the comparison you are asking about.) However it seems very unlikely that the Thien baffle would remove particles as small as those removed by a well designed cyclone. However, I would guess that it's similar to a less well designed cyclone in collection efficiency, and better in terms of flow resistance, size, and certainly price. Until I see evidence to the contrary, I would assume that any cyclone that handles the same amount of air and is more compact than Pentz's will be substantially less effective at capturing small particles (or require an enormous amount more power). This means more stuff will get to the filters, which will consequently need more frequent attention.

[Bruce Wrenn]

I have a cyclone, but also use a Phil Thein baffle ahead of it when using band saw, planer and jointer. I can't give you exact numbers, but google Phil Thein, and then look up my post over at NC Woodworker "Another Vote for Phil Thein's Baffle." You will see pictures of what separator ( baffle) got, and what went to cyclone. Impressive to me, and it's my unit.You do need to have good bags (1.0 micron, or smaller) on any DC unit.

[David Hostetler]

Apples to Oranges.

Bill advocates a system that will protect your lungs.

Phil advocates a system that will keep your filters from clogging so fast.

That they are sometimes compared is nearly almost always a cost comparison.

Not neccesarily true. Bill advocates that IF you are already using a single stage dust collector, keeping as much of the large, AND small stuff out of the filter in order to maintain air flow. On Bill's site he directly recommends for those with single stage DCs such as the HF 2 HP, a separator device (in the case of Bill's suggestion a Neutral Vane), and a micron or better filter.

This is not exactly ideal, both Bill and Phil will admit that. But given the budgetary hit most of us can't afford for a true full blown cyclone, a Thien fitted system is a bargain, and should be considered a minimum for dust collection...

How inexpensive can it be though? Here is how inexpensive.

HF 97869 2HP DC. Wood Magazine currently has a coupon for them for $137.99
Wynn 35A paper blend filter $103.00 + S&H.
Thien trash can cyclone separator. I based mine off of an open head 55 gallon drum. The pieces parts for that were...
Used 55 gallon drum. $39.00 (Others have reported them MUCH cheaper, all the way down to free.
4" S&D Street elbow. $1.69 (Lowes)
4" S&D pipe nipple. Can be free... I stumbled across it dirt cheap.
3/16" tempered hardboard. Free from scrap pile, or you can get a 2x2 piece from Lowes for about $4.50
1/4 -20 all thread, nuts, bolts, and fender washers. $5.00

The remaining costs are blood, sweat, and tears...

My system is a bit more than this as I opted for the spun bond poly on Bill Pentz' suggestion. And YES I KNOW I should have used 6", but I already had 4", including blast gates and all when I found Bill's information...

I have run a full barrel of material including cedar shavings, sanding dust, etc... through my system since I added the Thien separator, and have less than 1/4 cup of material in the bag of my DC.

[Curt Harms]

I figure Planers, Jointers, saws and such don't generate a lot of micron-size particles, more larger particles. I figure sanders create more float-in-the-air size particles. I KNOW the Thien baffle helps big-time with single stage machines keeping larger particles out of filters. The last time I removed my cartridge I got about a cup of wood flour out of it. That was way better than before the Thien baffle. Excepting a seldom used drum sander, all my sanders are hand held and hooked up to a Fein vacuum with bags & cartridge filter. Works for me.

[David Hostetler]

I have 2 Thien systems. 1 is a 20 gallon trash can separator hooked up to my Ridgid wet / dry vac fitted with a HEPA filter, the other is the 55 gallon drum hooked up to my HF 2HP DC.

The shop vac based one is used for the Shark Guard on my TS, and my sanders. I do not have a drum sander. The DC based setup is used for everything else.

I tap the canister down after each operation cycle before going back into the house. So far after a complete filling of my drum, I have only had 1/4 cup of wood flour in the lower bag. I can live with that...

[Bob Hallowell]

I do think it is apples and oranges but for me in an unheated garage that I vent right outside the Thein installed right in my grizz 2hp is awesome. it feels like the suction doubled getting rid of the bags and I get very little dust outside. I also run it alot when sanding at the lathe. I have no need for a cyclone to I have a heated shop.

Bob

[Greg McCallister]

This is a rather tricky question. One of the main reasons no one I know of has checked the difference between the two is how many own both and has the money to study it? I imagine there are those who have upgraded from the Phil Thien design but I have not seen any postings about the difference and to be truthful the cyclone has been around longer then Phil's baffle.
The main difference between the two is cost and space (airflow is another subject).
In my basement shop, space is a major factor and with my ceiling height a cyclone would be real hard to put in.
My Phil Thien modified system does a pretty good job - post located here. Modified outlet is here. Is it perfect, no - but is the cyclone perfect either?
The cyclone uses the same basic filtration (external filters) as a modified portable DC with a filter such as the Wynn Environmental cartridge filter. So actually removing the fines going back into your workshop is really the same as the filtration is actually the same.
A really big difference is how much horse power it takes to run the cyclone compared to the portable and what we really are comparing is airflow and separation or the debris from the airflow as to not plug the filters. Agreed a cyclone with a monster motor and fan will have a higher flow rate so lets look at it like this:

If you took a 3HP or better fan unit (used for the cyclone) and attached it to either a cyclone or Phil Thien baffle separator - what difference in separation would you get? This is the actual question.
Personally I think it would be very negligible.
Both separate the fines in the airstream from entering the filter.
The cyclone however requires much more HP to do so as the cyclonic action requires the air to circle the chamber 3 times or more - note on Bill's site he makes the comment of the loss of airflow to around 25-30% going through a cyclone. The Phil Thien baffle does not have as much loss as it actually drops most of the debris going around once resulting in a airflow loss of being somewhere around 10 to 15% and has a much smaller footprint.
I have already invested in the duct work, blast gates and flex which I would need to do anyway and amount of fines I get into the filter, so far, are minimal with extended use.
Sure I have to clean the filter once in a while but then again, do you have to clean the filter on a cyclone too? Sure you do as it does not separate 100% (reason for the dust bin).
I plan on upgrading the blower in the future for enhanced air flow (CFM), and if I need to upgrade to a cyclone the only cost I am out of is basically what it cost me to build the Phil Thien separator.
However currently, upgrading the blower is not even close to the top my list and a cyclone is well beyond that. I would rather spend the money on wood (this is a hobby you know, not who has the most tools contest).
If I had a big shop with unlimited funds and did this for a living I would go with the cyclone - sure, as it is the best money can buy at this time. But if space and cost is the major factor - I would go with Phil Thien's separator but buy the largest HP fan combo you can afford.
Something is always better than nothing.

[Greg Peterson]

Greg - I would like to congratulate you on your inspired design. You and Phil have created what I refer to as a hybrid DC system. While your design is not exactly a single stage or a cyclone, it represents a brilliantly elegant marriage of the best of both units.

As a hobbyist with a limited budget, the Thein-McAllister system presents a practical and cost effective solution for the home hobbyist. Bill Pentz has done the heavy lifting and raised awareness of the absolute need for effective DC. Certainly the more air that can be moved the easier this task becomes.

The hybrid system can be applied with great success. I have a Dylos particle counter in my shop and on any tool that has the full compliment of DC apparatus, the particle count remains well within the acceptable range.

Thanks again to you, Phil and Bill. The combined efforts of each has provided me the knowledge and designs to make my shop safer and more comfortable.