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Dust collection - what did I do wrong or right or what else can I try?

by WorksInTheory
posted 01-17-2018 12:53 AM


28 replies so far

View jimintx's profile

jimintx

913 posts in 1943 days


#1 posted 01-17-2018 01:06 AM

It seems to me that you have it just fine. Your design makes sense, and the blast gates are a must – which you have in the system.

I run a straight from the store, Powermatic system, and think it does great. Some of my runs are simply flexible 4” hoses, with no issues I detect. I cannot give any experience-based input on the HF based collection, but many, many others can speak from their experience there.

I am fairly certain that dust collecting might be the most over-worked problem in internet woodworking forums. Personally, I don’t think you can get it to 100% perfect. I say, don’t spend too much time thinking you are going to make your workshop living room clean. That’s ok, because you aren’t doing this work in the living room. Go with what you can reasonably assemble, and start making saw dust.

-- Jim, Houston, TX

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WorksInTheory

177 posts in 1961 days


#2 posted 01-17-2018 01:48 AM

jimintx – thanks for the response. I think you are so right and advice is sound.

My main 2 wonderings were 1) did I break a rule of some sort taking the HF and going up to 6” when it’s a 5’er, esp just to then go to 4” to the tools.

2) is there some guidance on performance if you just run it out the door vs into a Wynn filter, etc. I have the original 5 micron bag that I can sew so that it goes over the outlet as well if it needs ” resistance” etc.

View jimintx's profile

jimintx

913 posts in 1943 days


#3 posted 01-17-2018 02:11 AM

The 6” run going to 4” drops to tools is fine, and oft done. The 5” opening of the HF device should not imply that the main run to it should also be the same. Your scheme should give you good flow results. Similarly, smooth pipes will improve flow and produce a more efficient system than will the “corrugated” flexible tubes.

There is a definite pressure differential across any type of filter. Running the outflow out a door, or otherwise to the outside, has the effect of reducing “back pressure” on the system. It should directionally improve the operation of the system, not worsen it. Of course it might spray some dust into some area where it is not desired. That depends on your own location and criteria.

-- Jim, Houston, TX

View Rayne's profile

Rayne

1190 posts in 1898 days


#4 posted 01-17-2018 03:08 AM

When I was doing my research on duct size, increasing it was a bad move due to the DC not designed for a full 6” run. With yours though being only up to 11’, I can’t imagine it hurting it too much.

2) If you vent outside, you need to be able to bring air in as well. It was something about negative air pressure inside the shop from my memory. Someone with more knowledge will be able to explain it better or just search the forums and I’m sure you’ll run across that same question. Going through Wynn Filter is perfect in a closed garage.

View WorksInTheory's profile

WorksInTheory

177 posts in 1961 days


#5 posted 01-17-2018 02:55 PM

Thanks Rayne and jimintx

Rayne – my garage has more leaks in it than… uh a gossip column? a leek garden? I don’t have a good joke right there, should have thought that through. Anyhoo so I think the air will be replaced.

For clarity I am not using a Wynn filter. Trying to avoid the cost and the space. It’s just going out the back door (also another source of air replacement?).

jimintx – I have a thien baffle in there so hopefully hardly anything is coming out the door but I haven’t
“pressure” tested this theory yet. I have used it and nothing is coming out but I haven’t cut a lot of stuff yet or done the router, etc. But your words encouraging and validating so far.

View Carl10's profile

Carl10

115 posts in 815 days


#6 posted 01-17-2018 03:35 PM

Everything looks good with your setup, except the 6” pipe. DC optimization is all about restrictions, both on the input and output. Since you vent outside you have eliminated the bag restriction (good thing). It appears you have kept the 5” exhaust hose but increased the inlet to 6”. So you are trying to take in more air through a 6” opening than you can exhaust through the smaller 5” outlet. Making the exhaust 6” will help that balance.

So I mention the 6” inlet as a possible issue because of velocity. The larger the pipe the higher velocity that is needed to keep things airborne. The HF DC uses an undersized impeller greatly reducing the available CFMs (that’s why people upgrade the impeller). To keep things airborne in a 6” duct you want your velocity to be~3500FPM. To get that you need 686 CFMs in a 6” pipe. The stock HF DC with a 5” inlet can’t produce 600CFM. Now you have removed the filter restriction and opened the inlet so it is unknown what your unit can produce. You also do not have a planer which really needs a higher velocity to keep the chips from clogging.

Most would think (myself included) that with such a short run it wouldn’t matter. I actually had 6” duct running 8’ from my small cyclone. When I hooked up my Pitot tube and measured velocity I was surprised that it was less than 2800FPM. So I reduced my duct to 5” and tried again and my velocity was up above 3300FPM. Not as much as I wanted but much better and this is only a temporary setup until my shop is done. So bigger is not always better.

Also, removing too many restriction from your DC can also be bad. If you opened the inlet and exhausted outside without connecting your separator or ductwork you could burn up the motor. By letting the motor run too freely you draw more current and it can burn up. In your situation, the Thein separator adds about 3” of SP add your ducting and hoses and you have enough resistance not to worry.

Bottom line, check your horizontal ducting occasionally for any dust building up due to lower velocity. Usually with that size of DC 5” ducts are usually best. 6” is too big and 4” is too restrictive. Plenty of people run miles of 4” pipe and claim it “works great”, “no problem”, “plenty of suction” but I have yet to see anyone measure that kind of setup with a Pitot tube and provide real data points (Handheld meters are far too inaccurate). Will it move air? Sure. Is it enough? Probably a little better than a shop vac.

Hope that helps. Let us know how it works.

Carl

View Mainiac Matt 's profile

Mainiac Matt

9035 posts in 2687 days


#7 posted 01-17-2018 03:58 PM

If it works, it works… but there are a couple of principles that may have been misapplied.

Necking up from 5” to 6” didn’t really gain you anything, as it actually slows the air flow down in the 6” lines, and then accelerates it at the DC. As long as you still have enough velocity to keep the debris entrained in the air flow, you’re alright. But if you find debris accumulating in your 6” pipe, you’ll know why.

Running the 2” line to the router fence will likely not provide the collection you desire there, as the static pressure on most DCs won’t be sufficient to suck hard on small diameter pipe. (DCs are meant to move a lot of air quickly with little resistance). I have a 4” line to my router table cabinet, but use my shop vac at the fence, As shop vacs have a much, much greater static pressure and can pull sufficient velocity through the small diameter pipe (but they just don’t move as much total air).

Consider relocating your saw blast gate to the downstream side of the ‘Y’ so the line to the band saw has one less blast gate to go through. Each gate causes an increase in head loss in that leg of pipe. It may be a small loss, but every bit adds up.

-- Matt -- I yam what I yam and that's all what I yam

View jimintx's profile

jimintx

913 posts in 1943 days


#8 posted 01-17-2018 04:02 PM

Carl, first – thanks for the thoughtful input and guidance. Then, I’d like to discuss a little more, if you will.

Reducing the line diameter will increase velocity, and also decrease the flow rate – the cubic feet per minute. When you dropped from the 6” line to the 5” line and used your pitot tube, you measured a predictable velocity increase. I’d like to know the corresponding CFM flow rates in the two line sizes.

Back to the basis for my comments to the OP:
My underlying approach regarding dust collection embodies that I do understand fluid flow dynamics, and thus have thought about what I was assembling and how it would impact overall collection results. And then, overall, I prefer practical versus theoretical. So I prefer to test actual systems to see what they accomplish versus what I want to have them do, and balance that actual, observed data and performance against the cost and hassle to assemble something else.

In my case, once I determined that the 4” hose-based system worked well enough or better than i had hoped, I have so far left it alone. I know that i could improve the theoretical characteristics with different lines and hoses, but i don’t need to because it already does what i wanted it to.

I will rework parts of it some day, however, because there are components of it that sometime get in my way, or frankly don’t look as cool as i would like, so I will change some things. In the meantime, i am happily making sawdust and carrying on with my shop work activities.
.

-- Jim, Houston, TX

View Ripper70's profile

Ripper70

1262 posts in 1267 days


#9 posted 01-17-2018 04:43 PM

These two videos might be worth checking out:

Dust Collector Upgrade - Pt 1 - Upgrading to HEPA Cartridge Filter

Dust Collector Upgrade - Pt 2

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

View Carl10's profile

Carl10

115 posts in 815 days


#10 posted 01-17-2018 05:29 PM

Jim,

I got a hold of a free 1.5HP cyclone and did quite a few different modifications/ tests to monitor my ~70% performance improvement, so I had a lot of notes and tests to draw from. Unfortunately I can’t find the final compilation in the midst of my renovation chaos. I did find a rough note and my memory was a little off. 6” duct & hose ~2900FPM or ~570CFM, 5” duct & hose ~3800 FPM or ~ 520 CFM. I can accept the small CFM hit for better velocity.

When and if I find the official tabulation I’ll post an update.

Hope that helps

Carl

BTW: When I tried a 4” duct the CFMs dropped so much (below 400CFM) I didn’t even bother doing any official testing.

View WorksInTheory's profile

WorksInTheory

177 posts in 1961 days


#11 posted 01-17-2018 05:31 PM

Wow such great information and really appreciative of everyone taking the time to impart their knowledge. Some of these responses required thought and effort to type out. Thank you so much.

Maniac Matt – on the 2” at the router fence. My concern is running a shop vac, dust collector and the router all at the same time – could blow a circuit though I need to still figure out what circuit is on what. Old house, garage was add on and I may be running all from nearest outlet which is a lot splitting out of it.

Would changing it to a 4” until it hits the fence port and go down to 2” help? I was worried about the weight of that tubing on it.

On 6” vs 5” vs 4”. I was given some HVAC as well as dust collection stuff in 4” and 6”so I was just using that to save cost. Plus has anyone tried to get 5” stuff – it’s almost impossible to find, especially in fittings like wye’s etc.

I will take a look again at my blast gate config and see if I can remove one or move.

View jimintx's profile

jimintx

913 posts in 1943 days


#12 posted 01-17-2018 05:58 PM

All interesting, Carl, thanks.

Also of general interest is that well-known DC makers sell products, often at not-cheap prices, with 4” duct lines anticipated and set up.

The unit I splurged on is the PM 1300-TX-CK, so that rounds off to a thousand dollar machine. The inlet port that is built into the impeller shroud is a 6” metal flange, however PM supplies it with a plastic Y that splits into two 4” ports. The 6” sheet metal flange is not very deep and not designed to make attachment of 6” lines easy, but it it is do-able.

As supplied, this plastic Y device is attached onto the machine with sheet metal screws, and comes with a cap so that you can readily use only one side of it. Each leg of the Y has a 4-spoke grid to stop larger chunks from going in to the impeller. This Y-component adds to their costs one way or the other, yet they do put it on there. This sure indicates that their product designers think it is ok to run that DC with 4” lines. I mean, I have to ask: If PM thought their unit was optimized and performed best with a 6” inlet, wouldn’t they just ship it with the 6” flange and not add the Y?

-- Jim, Houston, TX

View YesHaveSome's profile

YesHaveSome

154 posts in 617 days


#13 posted 01-17-2018 06:09 PM

I have an Oneida Mini Gorilla with a 5” port. I asked Oneida if I could run 6” pipe from it and they said I would lose significant performance if I did. Just FYI.

-- But where does the meat go?

View WorksInTheory's profile

WorksInTheory

177 posts in 1961 days


#14 posted 01-17-2018 07:02 PM

Not to throw a wrench in the conversation, but considering also replacing the impeller w/ the Rikon impeller everyone is talking about. Someone mentioned that you need a “puller” to pull the old one out. Does anyone know what that is called or have a picture of that tool?

I am sure this is going to generate a debate as it seems there are 2 camps when it comes to doing this hack (or not)

View Carl10's profile

Carl10

115 posts in 815 days


#15 posted 01-17-2018 07:04 PM

Jim,

The single stage DC market has been fairly stagnant for the last 15-20 years. There have been impeller improvements and better classes of motors but the basic design is unchanged. These machines where never intended to be attached to large duct runs. The Y’s are a convenience to attach multiple machines at one time. Two 4” hoses is just less than one 6” hose, area wise. So you could theoretically run 2 machines simultaneously. Also, most woodworking machines come with 4” ports (or smaller). Years ago the idea was to just pick up the big stuff so CFM expectations where pretty low. Connect any of these 1.5-2 HP units to a machine with a 4” hose and you have pretty good dust collection. When you have several machines it gets to be a spaghetti mess of hoses and gates, so people started running ductwork up in the air to clean up the shop floor. Nobody tested the airflow after running all the ducts but they put a had to an opening it felt like air was moving so it “works great”

The other reason for 6” port is to maximize performance. If you put a 5” port on your machine the maximum advertised airflow would have to drop. You can look at most DCs and cyclones that use the same impeller and change the size of the inlet, outlet or both to get performance differences. I have seen the same cyclone use the same impeller one had a 6” inlet the other a 7” and the larger had better performance. It is silly to see a 2HP cyclone with an 8” inlet. The Grizzly 1.5HP cyclone comes with a 6” inlet (to get a better performance curve), but they include a 5” reducer with the machine (knowing that is the ideal duct size for a 1.5HP unit).

The bottom line for me is how good the real airflow is at the machine, not that I can still feel airflow. Someone told me about running his DC with 50’ of 4” line to his planer. He measured less than 200cfm and was getting clogs. 200 is better than most vacuums and “feels great”, but is obviously too low for a dust collector.

I hope that helps. Let me know if you have any other questions.

Carl

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Carl10

115 posts in 815 days


#16 posted 01-17-2018 07:10 PM

Yes do the upgrade! it is what should have been on the machine in the first place. Most all 2 HP units come with a 12” or larger impeller. HF uses a 10” forward curved impeller. The Rikon is a better 12” backward curved. The only issue gets into upgrading the impeller and not having enough inlet restriction to minimize current draw.

This is the puller: https://www.harborfreight.com/8-in-Three-Jaw-Gear-Puller-69224.html

BTW, last I heard there was a several month wait for the impeller.

Carl

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WorksInTheory

177 posts in 1961 days


#17 posted 01-18-2018 12:36 AM

Carl – I think you might be right. Been trying to find different sources but I think it’s only Rikon direct and also been seeing if there is another brand/model that also works.

View Dustin's profile

Dustin

688 posts in 1099 days


#18 posted 01-18-2018 02:38 PM

I just replaced my HF impeller with the Jet AB411059 12” impeller. If you are comfortable drilling out the center of the Jet from 19mm to 20mm to fit, it works very well (the shaft key fits, too). It was possible to trip the 20amp breaker it was on when I fired it up with no restrictions on the air flow, but once I added my cyclone and ducting, it fires up every time now with no problems. It is louder, but not unbearbly so.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

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WorksInTheory

177 posts in 1961 days


#19 posted 01-19-2018 01:46 AM

Thanks Dustin. It looks like this though has the fins in the same curvature as the stock HF and the Rikon is reverse which could be better?

View jimintx's profile

jimintx

913 posts in 1943 days


#20 posted 01-19-2018 03:39 AM

We are now officially in the dark hole of dust collection. To the extent that I contributed to this decline, I apologize. I do wish WIT the best of luck with it all, and hope you enjoy the explorations of vacuum indued fluid flow. I now give the heartfelt promise that with this post, I will cease to participate in this or any other dust collection threads. I will only enjoy from afar the amusement they provide.

.

-- Jim, Houston, TX

View Dustin's profile

Dustin

688 posts in 1099 days


#21 posted 01-19-2018 01:48 PM



Thanks Dustin. It looks like this though has the fins in the same curvature as the stock HF and the Rikon is reverse which could be better?

- WorksInTheory

I may be wrong, but I believe that the Rikon’s curvature allows for slightly less CFM but functions at a higher static pressure, where the reverse is true for the Jet. Either way, it’s a larger impeller (by 2.5” in diameter) spinning at the same speed, and it gives me much better airflow.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

View WorksInTheory's profile

WorksInTheory

177 posts in 1961 days


#22 posted 01-19-2018 04:11 PM

Dustin – good point – no matter what it’s an improvement.

Since I wasn’t in a hurry, I called Rikon (so I don’t have to drill) and they were like, “let me guess Harbor Freight”. Seems they have come to terms and woken up to the opportunity and no longer require serial number and such. He said they used to sell 20 a year and now they are selling hundreds and said, “Thank You Harbor Freight”. ha. Well explains how they basically doubled the price!

They are expecting another shipment in 2 weeks or so so hopefully within a month I will get mine and hopefully it’s as easy as dropping it in. Then I am hoping that all that overcomes any messup I did with how I piped everything – sort of saying that in jest and sort of serious ;-)

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WorksInTheory

177 posts in 1961 days


#23 posted 01-19-2018 04:14 PM

jimiintx – just saw your last post slip in there – don’t say that. I for one have learned immensely from the interchange on this and other forum chains. As long as it’s healthy and polite I see no issue, dark hole or not. Everyone can gleam what that deem useful and “ffwd” through other stuff. In either case one person’s experience can save another person a lot of pain and accelerate them towards their goals and making saw dust! I appreciate your input and everyone else’s here so far.

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WorksInTheory

177 posts in 1961 days


#24 posted 01-19-2018 04:16 PM

Thanks Carl10 – so why did you only choose the 8-in Three Jaw vs the 3 puller set that had the diff sizes – seems only a few bucks difference but more options for future use?


Yes do the upgrade! it is what should have been on the machine in the first place. Most all 2 HP units come with a 12” or larger impeller. HF uses a 10” forward curved impeller. The Rikon is a better 12” backward curved. The only issue gets into upgrading the impeller and not having enough inlet restriction to minimize current draw.

This is the puller: https://www.harborfreight.com/8-in-Three-Jaw-Gear-Puller-69224.html

BTW, last I heard there was a several month wait for the impeller.

Carl

- Carl10


View Carl10's profile

Carl10

115 posts in 815 days


#25 posted 01-20-2018 01:14 AM

You asked what the tool looked like so I showed that link only for the picture.

The impeller curve for both the Rikon and Jet are backwards curved. These are much more efficient blades than the original HF forward curved. The Jet would act forward curved because it would be installed backwards in the HF. Jet blowers spin in the other direction.

Carl

View Redoak49's profile

Redoak49

3925 posts in 2347 days


#26 posted 01-20-2018 03:31 AM

Some day some one will actually do a good job of actually measuring airflow and static pressure with the HF modifications. I mean measuring with something other than a fan anemometer.

Just saying that it feels so much better does not say much. It would be a real service to accurately quantify all the HF modifications.

View Bob5103's profile

Bob5103

125 posts in 1192 days


#27 posted 01-20-2018 05:02 AM

I upgraded my HF DC to the Rikon impeller, and did a review of it here: https://www.woodtalkonline.com/topic/23656-harbor-freight-rikonstein-dc/. It is as detailed as I wanted to get for a cheap DC. Bottom line is, for me, the upgrade was well worth the effort. Part of the success, I believe, is that I exhaust outside so the restriction of a filter is eliminated.

View WoodES's profile

WoodES

141 posts in 2050 days


#28 posted 01-21-2018 04:04 AM

I come to the conclusion that one can’t think of Dust Collection as one would think of HVAC ducting. They are fundamentally different while looking and acting in a similar fashion.

HVAC – is fundamental a supply of air to many locations simultaneously (outlets/vents). To function correctly the duct must be reduced in area to balance the air pressure (supply) at the outlets.

Dust Collection – for the home shop, functions as a 1 to 1 relationship (e.g. 1 tool supplying dust to one collector), thus it is detrimental to reduce the size of the duct. 1. To maximize the dust collection at the tool, one must maximize the length of the run without a change in size. 2. A reduction in collector size has a reduction in volume of air moved (this assumes that the fan speed remains constant). Remember the blast gate control the air flow.

I used 6” duct until I reached the tool then had short runs of 4” pipe tube to the tool. Seems to work good for a 2hp system and about a 30 to 40 foot run of duct.

This is the long way of saying, keep the duct the same size until you reach the tool.

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