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


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