HF Collector - What Duct Size?

[Adam Kaufman]

Hi all, I just bought a Harbor Freight collector and am in the process of building a Thien baffle for a 30 gal. can. Eventually, I'll get the Wynn cartridge.

I was originally going to go with 4" duct everywhere, but after much reading of Bill Pentz and others, I see that 4" isn't recommended. My shop is 20' x 18' and my longest run should be to my Unisaw (at most 20' up, over and down). Unfortunately, my ceilings are only 7' 2" so I'd rather not run 5" or 6" duct work. If I need to, I could keep it against the wall and the up between the joists, but this will add length.

So, I guess my questions are, is anyone using 4" with this setup? And how well does it work?

Thanks!

[Anthony Whitesell]

I used the rigid ABS 4" flex tubing/hose. I should have gone with at least PVC but I didn't know better. Now that I do know, I would have gone with 5" sheet metal just to reduce the SP losses. The Thien can will cut into your allotted SP on top of what you have lost with the piping. If you ever upgrade, you will never use the 4" again. The smallest you will use in the future will be 5". Might as well go with it now. Sometime you have to spend money to save money. If the port on the HF collector is 5", take full advantage of it.

[David L Morse]

The HFDC with a Thien baffle in the collector ring and a Wynn filter will pull 470CFM through one of the 4" ports on the Y adapter with the other port blocked. Add 10' of 4" flex tubing and the flow drops to 220CFM. With an external separator the performance will likely be worse than that since you'll be spinning the air twice.

[Robert Delhommer Sr]

In my 20' x 20' shop I have a HF 2Hp DC and a Thien separator and run 4" PVC around the shop and very happy with every thing. :)

[Stan Mitchell]

From my experience, a 4" line will likely work - but with a trade off.

Ideally you should run 6". With a 4" I suspect that you'll only be able to have one gate open at a time and have effective suction.

A 2hp system in your size shop and a 6" main - you probably could keep 3 gates open at the same time. At least that's what I've found to be true with my 2hp system with a similar size shop.

[Stew Hagerty]

I have a HF DC with a Winn filter, but without the Thien Baffle. I run one very short hose from one side of the "Y" to my miter station, with a blast gate of course. From the other side of the "Y", I run a 10' section of 4" PVC followed by a splitter with a gated 2 1/2" leg going to my drill press, while the 4" continues through a couple of feet of hose to my Trash Can separator. From the separator, I have hard plumbed and gated 4" sections, just a couple of feet long each, going to my TS and a floor sweep. The third 4" line from the separator, yes also gated, connects to a 21' long (when extended) Dust Right® hose system with their "handle" on the end. I open the gate & connect it to whichever of my other tools I am using at the moment. That includes my 5" disc sander!

And before I hear from all of those that are going to say that using a DC system of a handheld tool like a sander doesn't work, let me tell you about me... Back in '08 I contracted a virus that spiked my fever for over 30 days, filled my lungs for more than 3 months, almost killed me 3 times, and left me with a severe case of asthma, not to mention triggering the immuno-neurological disorder that put me in a wheelchair. Saying that I cannot tolerate dust in the air is a ridiculous understatement. So when I tell you that it works, and that it works well enough for power sanding that I don't even have to wear a filter mask, I know what I am talking about. Numbers, flow tables, and statistics be damned.

Anyway... I am completely happy with my setup. It works very well. Of course it doesn't pick up every little bit from my vintage 80's Sears saw, even though I have plugged all the openings the best I can. But and 5" or 6" pipe would still not get all of that. I wouldn't think twice about doing what you propose.

[Art Mann]

I would not run 6 inch duct work because the Harbor Freight dust collector is not strong enough to provide sufficient velocity to keep the heavier materials in suspension. You are likely to get dust settling in the lower parts of the ductwork. I haven't heard how much static pressure loss you get through the Thein separator, but it certainly isn't zero. I'll bet its less than a simple trash can separator but it will still compound the problem of maintaining sufficient velocity to some extent.

I can't argue with Stew Hagerty's experience but I can say I had exactly the opposite experience trying to adapt my dust collector to a 1-1/2 inch hose from a 4 inch one. I got much better suction with my shop vacuum. The reason is that dust collectors are designed to move large volumes of air at low static pressures whereas the shop vacuums are designed to maintain suction even with a small hose and high static pressure. I suggest you rig up a temporary 1-1/2 inch hose adapter from your HF collector and compare its performance with a normal shop vac if you have one. Let the results of your own experiment be your guide for that application. If you decide to go the shop vac route for hand power tools, be sure to replace the cheapo paper sheet filter with a replacement HEPA filter or you may just blow the fine dust back out into the air.

[Greg Peterson]

The inlet on the DC is 5", so I run a 5" x 8' flex hose from my HF unit to whatever tool I am using. I have the Thein baffle and a Wynn cartridge filter. I have a Dylos particle counter that tells me if my DC is working well. Or not.

Given the numbers I get on my Dylos unit, I am skeptical that the HF unit is powerful enough to power a DC network. I don't have to roll my HF DC unit very far as it is situated in the middle area of the shop, so hooking it up to any machine is not a big deal.

[Ole Anderson]

And contrary to one comment, a HF DC (I presume the (almost) 2 hp one) simply hasn't the chops to allow multiple open gates or to use with any sort of extended duct system and maintain any manner of effective fine dust collection capability on most tools.

[Stan Mitchell]

And contrary to one comment, a HF DC (I presume the (almost) 2 hp one) simply hasn't the chops to allow multiple open gates or to use with any sort of extended duct system and maintain any manner of effective fine dust collection capability on most tools.

I'll concede on this for lack of direct experience.

The HF unit must be a real dog in comparison to the 2hp units that I've used.

[Greg Peterson]

The HF unit is rated at 1.5 HP. I assume this rating is overly generous.

I achieve acceptable results on most operations. There are times where all my DC methodologies produce less than ideal or safe results.

DC for most power tools is ineffective. The end user is largely responsible for creating a DC solution, which includes-but not limited to-a DC unit that moves enough air.

We're talking about dust, not chips.

[Wade Lippman]

I can't argue with Stew Hagerty's experience but I can say I had exactly the opposite experience trying to adapt my dust collector to a 1-1/2 inch hose from a 4 inch one. I got much better suction with my shop vacuum.

My TS has a 1.5" hose going to the guard. It picks up what the blade throws out, but it hardly has any suction at all. A vacuum would be much better; and that is with 3hp. (Hey, I agreed with you!)

[Stew Hagerty]

My TS has a 1.5" hose going to the guard. It picks up what the blade throws out, but it hardly has any suction at all. A vacuum would be much better; and that is with 3hp. (Hey, I agreed with you!)

Are you using the guard hose only? Or, are you using 4" below the saw AND the 1 1/2" on top? When I use my DC with a 4" to 1 1/2" reducer and a hose running to my disc sander that is the only open blast gate. And like I said, it works. You can hear and feel the suction through the sander's "holes". And, when you use it, there is NO airborne dust perceptible enough to be detected by my hyper-sensitive nose. There is also NO significant dust left on the board being sanded. Like I said, it works. I don't even own a shop vac. I have absolutely no need for one. It would just be in the way and would get set out in the Spring for the next Association Garage Sale. Those who say it doesn't work are flat out wrong!

[Art Mann]

If you don't own a shop vac, how do you know that your setup is good compared to using a shop vac? I own both and have directly compared the two methods. Its not that the dust collector didn't work, but the vacuum worked noticeably better. If it is good for you then that is good enough but I would still encourage a direct comparison for someone who is about to invest money and time in one solution or the other.

[Stew Hagerty]

If you don't own a shop vac, how do you know that your setup is good compared to using a shop vac? I own both and have directly compared the two methods. Its not that the dust collector didn't work, but the vacuum worked noticeably better. If it is good for you then that is good enough but I would still encourage a direct comparison for someone who is about to invest money and time in one solution or the other.

I didn't say I never tried one. When I was first setting up my shop I used my brother's vac before I got my DC set up. My DC does the job more than twice as well as his Pro-Series Shop Vac did. I still had to wear a mask when I was using the vac.

This is what he has:

http://www.shopvac.com/wet-dry-vacs/vac-details.aspx?vacId=252&vacSKU=962-16-10 (http://www.shopvac.com/wet-dry-vacs/vac-details.aspx?vacId=252&vacSKU=962-16-10)


So, no it's not a Festool, but it's not some slouch vac either.

[Art Mann]

If he/you didn't replace the simple sheet filter that comes with that type of vacuum with a HEPA filter, then the machine was just sucking fine dust in one hole and blowing it back out another one. Maybe that is why you had such a bad experience. The HEPA filters are designed like the Wynn filters that are often used as replacements for the HF unit but on a smaller scale.

Edit: Here is a link to the filter I have been using.

http://www.homedepot.com/p/Multi-Fit-HEPA-Cart-Filter-VF2006/100582455#.Uo7CyeJIVgg

[Stew Hagerty]

If he/you didn't replace the simple sheet filter that comes with that type of vacuum with a HEPA filter, then the machine was just sucking fine dust in one hole and blowing it back out another one. Maybe that is why you had such a bad experience. The HEPA filters are designed like the Wynn filters that are often used as replacements for the HF unit but on a smaller scale.

Edit: Here is a link to the filter I have been using.

http://www.homedepot.com/p/Multi-Fit-HEPA-Cart-Filter-VF2006/100582455#.Uo7CyeJIVgg

No, he didn't have one in it but I installed one before I started using it. I am not someone who doesn't know any better. Because of my condition, I thoroughly checked out each and every aspect of dust collection and control in my shop. I researched it all before starting anything. I tested out several ideas. Then based on my health needs, my shop layout, the tools I planned on using, and of course my budget. I believe that it doesn't make sense to spend more than you need to in order to achieve your goal. After test various DC systems, I felt that the Harbor Freight model fulfilled both my needs and my budget. I also determined that a shop vac was redundant. The HF DC did everything I needed it to do, up to and including outperforming a hepa-filtered shop vac.

[Stew Hagerty]

You know... I'm not trying to pick and fights here or to stir up some kind of huge controversy. I'm also not attempting to rewrite the laws of physics. A question was asked about using 4" piping with the HF DC. I answered that question based on my own research and experience. I then added that the HF was far more versatile in a small shop than just being used for large machines because I felt that the comment fit well within the thread's parameters. Again, that comment was also based on my own research, testing, and experience. I say that it works. I also say that if it works good enough for me, with the extensive health problems that I am burdened with, then I have no doubt whatsoever that it should work well for others.

[Ole Anderson]

The HF unit must be a real dog in comparison to the 2hp units that I've used. Someone posted the fan curve of the HF unit recently, and from what I remember it was quite pathetic compared with an Oneida 2 hp SDG which cranks something like 800 cfm at 7" of suction. And Stew, a HF DC with 4" diameter piping is going to be a whole lot better than nothing, or just using a shop vac. I got by with a 1 hp Penn State double bagger with 10 feet of 4" flex for years and thought it did a pretty good job as a single hose collector.

[Stew Hagerty]

And Stew, a HF DC with 4" diameter piping is going to be a whole lot better than nothing, or just using a shop vac. I got by with a 1 hp Penn State double bagger with 10 feet of 4" flex for years and thought it did a pretty good job as a single hose collector.

You're right Ole, and just like you, I think mine does a pretty good job. Believe me, if it didn't collect and filter the dust effectively (Thank the Winn Filter and Cyclone), I would have a different unit in there immediately. As I've said, I cannot tolerate dust particles. Whenever it looses it's effectiveness, or out & out dies, I will more than likely upgrade to a cyclone unit such as one of these three:

http://www.pennstateind.com/store/TEMPEST.html

http://www.oneida-air.com/inventoryD.asp?item_no=XXP010100H&CatId={B75F8739-54DE-47CA-A8FE-4FE9AEFDCC1C}

http://www.grizzly.com/products/Cyclone-D-C-1-1-2-HP-2-Stage/G0703

However, until then, I am quite satisfied with my trusty HF-Winn-Trash Can system. I does everything I ask of it, including collect dust from my disc sander. Plain & simple.

[Michael W. Clark]

Again, that comment was also based on my own research, testing, and experience.

How many CFM are you pulling through the branch that is connected to the sander? You are taking a huge hit with the 1-1/2" port. You may get adequate capture at the sander, but you also have to maintain velocity in the 4" duct to keep the dust entrained in the air and delivery it to the collector. You need 72"wg of SP to get 300 CFM in the 1-1/2" port and that will only give you ~3500 FPM in the 4" duct which is very marginal.

I have a 1.5HP Jet and tried connecting it to a ROS (1-1/4" port) and it did basically nothing. I have also tried it with mulitple 4" gates open and found it lacking. I am upgrading it to all 6" and 5" duct with appropriately sized connections at the machines. I have a small shop and no room to really wheel it around with a hose connected. It is better for me to have short runs of hard pipe and a stationary system, less overall SP loss and therefore more CFM from the fan.

Mike

[Stew Hagerty]

How many CFM are you pulling through the branch that is connected to the sander? You are taking a huge hit with the 1-1/2" port. You may get adequate capture at the sander, but you also have to maintain velocity in the 4" duct to keep the dust entrained in the air and delivery it to the collector. You need 72"wg of SP to get 300 CFM in the 1-1/2" port and that will only give you ~3500 FPM in the 4" duct which is very marginal.

I have a 1.5HP Jet and tried connecting it to a ROS (1-1/4" port) and it did basically nothing. I have also tried it with mulitple 4" gates open and found it lacking. I am upgrading it to all 6" and 5" duct with appropriately sized connections at the machines. I have a small shop and no room to really wheel it around with a hose connected. It is better for me to have short runs of hard pipe and a stationary system, less overall SP loss and therefore more CFM from the fan.

Mike

Wow, Mike that was a whole lot of numbers and stuff.
Perhaps I didn't explain myself well enough.

My system works!

My medical condition makes me hyper-sensitive to dust.

I am not bothered one iota by dust in my workshop.

That includes not only when I operate my machines, but also when I use my handheld power tools .

That includes my disc sander.

My system works.

And if I am not bothered by the dust I generate then it should work fine for others as well.

My system works.

[Michael W. Clark]

I'm glad it works for you Stew. I would add a port on the 4" duct to bleed some air in. This will keep the 4" duct swept clean and minimize the risk of material build up in the duct.

Just thought you might have had some numbers from your research and testing.

[Stew Hagerty]

I'm glad it works for you Stew. I would add a port on the 4" duct to bleed some air in. This will keep the 4" duct swept clean and minimize the risk of material build up in the duct.

Just thought you might have had some numbers from your research and testing.

My testing was practical rather than scientific.

As for the "duct", it is a length of 1 1/2" hose connected to a long 4" Dust Right expandable hose attached to a blast gate that leads, via a short flexible hose to the trash can cyclone. I've been using this same length of 4" Dust Right hose for 2 years now and the only thing that has ever built up in it was shavings from when I try to vacuum up too large of a pile of handplane shavings all at once.

[Greg Peterson]

My testing was practical rather than scientific.


I'm not challenging your experiences, I'm just not willing to be a canary in the coal mine. I use a particle counter to show me precisely how clear the air in my shop is.

I have a Delta down draft sanding table that I connect to the DC (Wynn cartridge filter and Thein baffle). I also connect the shop vac (with Dust Deputy and hepa filter) to the ROS. I wear a respirator during sanding operations, based on the particle count I am getting. Obviously our experiences differ. I wish you continued health and success with your configuration.

[Michael W. Clark]

Stew, I was genuinely interested in your numbers and research. I imagine you did your due diligence given your situation. There are several of us DC geeks on here that like to see numbers because we know the mfg numbers are a stretch at best.

I'm glad your system is meeting your expectations.

[Art Mann]

I just repeated the experiment tonight that I did a few years ago and got the same results. I hooked up my Delta 50-760 through a short length of flex hose, an 8 foot length of 4 inch galvanized pipe, an adapter and about 6 feet of vacuum hose. I bypassed the separator to get maximum suction. It worked okay but I repeated the same experiment with my 10 amp Genie shop vacuum and the suction was noticeably stronger. This experiment isn't hard to do. Since there is some difference in experiences here, I would suggest that anyone who is contemplating both methods to try both and use the one works best for them.