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bglenden

Harbor Freight DC - can it pull through 6" pipe?

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I have the Harbor Freight DC with an aftermarket Wynn filter. At the moment I move a 4" hose around from tool to tool, which works but is kind of a PITA. My next major purchase will be a larger (3+ HP) cyclone. From what I can tell 6" ducting seems to be the sweet spot for a "one machine at a time" shop. If I start installing some duct now to get some permanent machine connections, will the HF DC have enough "oomph" to get the dust through the 6" ducts, or will dust be piling up and instead I should wait to get the bigger machine first?

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If your plan to upgrade to a 3hp is definite, and not just a possibility, put in 6".  But you will be disappointed with the HF performance.  I put in 5" with my HF unit because I will never need anything over 2hp, if and when my unit croaks. 

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Yeah, the plan is to put in 6" pipe so I will be ready when I get a bigger unit (which is a definite plan). But I guess the consensus is that 6" is just too big for the HF unit. :-(

 

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You can't use bigger pipe than your inlet diameter.  That will give you terrible performance.  I have a 2HP DC and there's no way it would work with 6" pipe.

The good news is that you can go ahead and duct your entire system with 4", and when you replace your DC in the future you can just swap out the 4" main with 6" and leave the drops as they are, so you won't have to replace all the duct.  Also, using 4" S&D PVC will save you a boatload over using Nordfab and the like, so you won't be out much more than your labor.

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I don't understand why a 5" inlet to 6" pipe would have terrible performance, i.e. I think you would still get more CFM than going from the 5" inlet to a 4" pipe. I imagined the issue would be whether you would have enough velocity to transport the dust from the source to the collector. (Also, although I'm not looking to put a lot of mods into the HF DC before I replace it, it looks like replacing the 5" inlet with a 6" one is not a big job.)

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I don't have the energy or communication skills to explain the physics, but trust me, you can't do it. The information is out there if you gargle hard enough.

Sent from my SCH-I545 using Tapatalk

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OK, thanks for patiently providing the info you did!

(I actually am a physicist/astronomer, but admit fluid dynamics has never been my thing).

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1 hour ago, bglenden said:

(I actually am a physicist/astronomer, but admit fluid dynamics has never been my thing).

 

Well jeez man, if you can wade through text of that density, you can surely handle this lightweight stuff.  Have a little Bill Pentz to start with...

http://billpentz.com/woodworking/cyclone/ducting.cfm

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I'd consider a slight variation on what Eric said above.  Just do it now without the 4" mains at all.

Run 6" horizontal runs and any drops (like from up high to the DC unit).  Make all connections up from tools 4" pipe.

The issue with the larger pipe is that for a given CFM it won't really sustain the linear air speed necessary to move the wood dust.  My my sense on that is on a horizontal run or a drop back down, it's less critical.  So some might build up in the pipe.  it can't be worse than running 4" all around.

The 4" uplifts from the tools are a different story.  It's important to keep up the linear speed up in those pipes, because this is where it IS important to keep the dust moving properly.  Otherwise it'll just fall back into the tool or not be colllected properly.

When you upgrade to a larger unit that can move more air, you might be able to replace some of the 4" pipes with larger pipes, to get more CFM right to the tool. 

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Yeah I'm no physicist either, but it seems that the 5" inlet is limiting the airflow to a certain point, then you're putting a larger pipe on and reducing the flow even further by adding all this extra air space.. It think it'd be worse than 4 or 5 inch.

Not to mention HF puts a 4" splitter on the unit, probably implying thats the right size for the available power. Drain pipe is cheap and easy to install/replace your mains when you move up to 6". Theres no need to glue anything, foil tape works great for that little bit of overkill and can be removed later.

Sent from my SAMSUNG-SM-G890A using Tapatalk

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Thanks everyone for all the helpful comments and ideas. Net of everything it seems like the sensible thing to do is wait until I get the bigger machine and install the pipe after, and live with moving the hose around until then.

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I did have the HF collector and had 6" pipe. I have a 30' ft main trunk with 4 6 inch drops, reduced to 4" going to the tools. It did a decent job of getting the chips  into the bag. I did not have a filter just the bags. I have recently replaced it with a Grizzly G0440 cyclone, (2hp).

 

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2 hours ago, Tim Compton said:

I did have the HF collector and had 6" pipe. I have a 30' ft main trunk with 4 6 inch drops, reduced to 4" going to the tools. It did a decent job of getting the chips  into the bag. I did not have a filter just the bags. I have recently replaced it with a Grizzly G0440 cyclone, (2hp).

 

Ahh, experience rather than speculation - thanks!

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i am wondering about the Grizzly 2 / 3 HP  single stage DC. both have 12 3/4 inch impellers with 6 in. and 7 in. intakes respectfully. Would a hybrid system of an impeller this size , Dust Deputy XL ( 6 inch intake/out take ),with stock Grizzly cannister above  and a Wynn Env. Nano with a cleanout pan/bin on bottom replacing the clear bag  get there in terms of performance ?The impeller mounted horiz.  directly to the cyclone and filter stack of approx. 350 sq. ft.  We have all seen these before , but the HF is closer to 1 1/2 HP  and has a 10 or 11 inch impeller. Could this bigger impeller size / filter size combination be enough to use 6 inch main lines in a modest sized shop ? I had planned to go 6 inch virtually to every tool , with only a couple  dual 4 inch  hook ups. Anybody think  this is foolish .Thanks.

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Two potential issues for the OP are turbulence at the inlet and low velocity in the piping.

To lower the issues with turbulence at the inlet a smooth transition should be made, the longer the better but any short transition (4-6" long) would be much better than just slapping the 6" over the 5" inlet and tightening down.  If you know someone with some spare time on a supercomputer with fluid dynamics software they could model the impact of various transitions. :)

The other issue is the reduction in flow speed in the 6" pipe, this will "likely" be enough for heavier chips to fall out of suspension, by likely I mean absolutely.  This is less of an issue in the horizontal runs than the vertical ones but may still cause partial blockages which are a pain to find and clean.  

The calculations for air speed are simple* (especially someone with a healthy math background) and you want to keep roughly 3000 fpm in the horizontals and 4000 fpm in the vertical runs.  

* Simple in the basic formulae are simple but truly exact ones are HIGHLY complex but the 3000/4000 figures are formulated for use with simple volume/time formulae.  The only issue is you need reasonable CFM figures and a reasonable static pressure for the system otherwise it becomes more of a WAG than science, but you may be able to find some actual measurements for a "similar" system to yours or you could measure it yourself but I doubt you want to send much time or money optimizing a temporary system.

Now for the simple, practical advice.  Just go ahead and plumb a 6" system into your shop, hook up the HF and if it doesn't work well enough just switch back to the 4" hose dance for now, nothing lost since you plan for a cyclone in the future anyway and can just utilize it then.  The only thing you lose is the extra time and materials it takes to hook the new system to the HF collector for the test.

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On 2/15/2017 at 0:32 PM, bglenden said:

I don't understand why a 5" inlet to 6" pipe would have terrible performance, i.e. I think you would still get more CFM than going from the 5" inlet to a 4" pipe. I imagined the issue would be whether you would have enough velocity to transport the dust from the source to the collector. (Also, although I'm not looking to put a lot of mods into the HF DC before I replace it, it looks like replacing the 5" inlet with a 6" one is not a big job.)


The answer appears to be, YES, if you replace the impeller and want to risk overwhelming the motor in the future. But hey, modify it to something like this, then in the future all you would have to replace if the motor fails is the motor or blower\impeller unit.

This guy used the RIKON 12" impeller from one of their units. Its mentioned in the video
 

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On 3/24/2017 at 7:46 AM, Waldvogel Review said:


The answer appears to be, YES, if you replace the impeller and want to risk overwhelming the motor in the future. But hey, modify it to something like this, then in the future all you would have to replace if the motor fails is the motor or blower\impeller unit.

This guy used the RIKON 12" impeller from one of their units. Its mentioned in the video
 

Great answer... Many examples of the HF overperforming when using Rikon Impeller. The amp draw only increases fractionally over the factory impeller because of the reversed fins, but performance gains from 10" to 12" impeller are huge and well documented. I would still say you are ultimately looking at needing a 2.5 to 3 hp or do what Stumpy Nubs did years ago and add another HF DC to increase flow. He was able to pull a Bill Pence sized cyclone with that setup... called it the "Frankencyclone." I think his dad still uses it.

http://stumpynubs.blogspot.com/2013/03/episode-31-franken-cyclone-lives.html

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I had a 1.5 hp JDS dust collector with a 6" inlet.  Like you, I was prepping for a move to a larger cyclone and put in 6" pvc pipe.  My runs were really short, 10 feet max.  I had better performance at the dust producing machines, like the drum sander and band saw.  I had major clogging problems with the planer though.  But I had major clogging problems with the planer with the 4" flex hose that was there before.  So it wasn't too much of a problem, but cleaning out flex hose on the floor is a lot easier than cleaning out 6" pipe on the ceiling.  Now that I have my cyclone, I have since added a thien baffle on a trash can on the line to the planer to make the primary waste producer dump its chips in a container that's easier to get to and so I don't overflow the bin on the cyclone.  Had I done that with the smaller DC it would have prevented the pipes from getting clogged but maybe made the collection at the planer a fair bit worse from the reduced airflow.  

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On 2/15/2017 at 11:34 AM, bglenden said:

I have the Harbor Freight DC with an aftermarket Wynn filter. At the moment I move a 4" hose around from tool to tool, which works but is kind of a PITA. My next major purchase will be a larger (3+ HP) cyclone. From what I can tell 6" ducting seems to be the sweet spot for a "one machine at a time" shop. If I start installing some duct now to get some permanent machine connections, will the HF DC have enough "oomph" to get the dust through the 6" ducts, or will dust be piling up and instead I should wait to get the bigger machine first?

Hi.  What did you decide to do?  I'm just putting together my DC system and was leaning towards the HF with a Wynn filter and the Rikon impeller upgrade including opening up the inlet to 6".  Also adding the 6" SDD to the system as well.   I too want to run 6" ducts and it seems to work according to Gray house studios.   Just wondering if this is the best way to go.  Have you thought about or by now maybe added the Rikon to your HF?  Appreciate the help! Thanks

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I didn't do anything other than save my nickels and dimes (quite a few of them) and bought a 5 HP Oneida. I haven't put ducting in yet so I'm still pulling a 4"  hose from machine to machine. (I'd like to do Nordfab ducting but don't want to pay for it, so I'll likely end up with thin wall PVC). Sorry I don't have an answer to my original question!

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Just to throw some real world experience at the math & theory nerds, I have this exact setup and it works great. :)

2hp HF DC necked up into a Super Dust Deputy which is necked up to 6” PVC main. I have >35’ of main with 4” drops for the planer, table saw and my workbench. I have several 2.5” drops built into the bench and elsewhere in the shop. My highest rise is 6-7 feet. The only place I have any issues is the planer’s flex hose which is the drop closest to the source. It tends to get clogged when I get unusually long shavings. I have good pressure and airflow at even the farthest drop. Ignore the naysayers. It may not be running at peak efficiency but it works just fine.

I just today added a Grizzly H5783 canister filter from Amazon and it’s running better than it ever has. 

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So, I've had the HF DC for like 15 years and mine has gone through several "modifications", but I can tell you the three best things I did were to 1) add a pleated filter, which you did 2) Add a Super Dest Deputy 3) Swap out the impeller. Rikon makes a 12" impeller that is a direct replacement. When I did this, I also cut my inlet hole bigger, to 6" (so I guess that's 4 things). It is a totally different machine now. I run it to my SupMax 19/38 drum sander, 15" planer and 12" joiner and leave all the blast gates open. 

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