Use the grizzly and just sell the other one and use the money to buy duct for your system.

 

Use the grizzly and just sell the other one and use the money to buy duct for your system.

- papadan

^^^^^ Yep. This question comes up about once a year (although it's usually a matched pair of HF DCs). But I've yet to go back and see someone explain what a great idea is was. I think Stumpy Nubs did that (with the HF units), you might check his stuff and see what happened, but I don't recall him saying it was a great idea either (I could be wrong).

 

1) No, it won't work.

2) No, it won't work.

3) Yes.

You are always, always better off with one big motor and one big impeller.

 

Don't try to mix two DCs into the same system. Either use the larger one, or if you have room you could effectively create two systems by collecting some tools that are close together into one DC then the rest into the other DC. You might save on some pipe but it will cost you in floor space.

 

I say keep the #2 dust collector which is the…1 HP UFO. Handy for mobility. I have a 3HP Grizzly that is stationary… and I just picked up a 1HP Delta I plan to use on a cart…think of a super shop vac. Or can be used on a downdraft table… or…. finishing ventilation… or to tackle a machine that is 20' or further away from your main 2HP dust collector. Can use the #2 DC for lots of good uses. Granted, I paid $10 for the 1HP Delta though.

 

I want to do the same thing with 2 identical DCs. How do you put them in parallel?

 

They would have to both go into a manifold that is twice the cross sectional area of one DC, two six inch pipes into one eight inch pipe. A plenum (big box where all the pipes connect) might work but it will collect a lot of dust.

The problem is keeping the two DC’s synchronized. It might be difficult to find a wye fitting for that too.

 

It won't work the way you think it will.

 

There is a fourth option. Sell both and buy a bigger unit.

 

Hook one up to some of your machines and hook the the other one up to the remaining machines and shorten your runs.

 

I want to do the same thing with 2 identical DCs. How do you put them in parallel?

- 1stJustJoe

Someone here did that, and the pic I saw had the main truck running to the DCs. There was a wye that branched off to the first one, then the truck went past it to the second one where an elbow led into the second DC. As I recall, the 2 blowers were set at 45º angles to the trunk, so the branches fed straight into the blowers. Maybe whoever it was will see this and link you to the pics. It's not something I endorse, but the poster seemed to indicate it worked well. That's the catch phrase though, we all have a different opinion of what "works well".

 

There is a fourth option. Sell both and buy a bigger unit.

- Kudzupatch

Hook one up to some of your machines and hook the the other one up to the remaining machines and shorten your runs.

- bondogaposis

Only two options I would consider. However it is your shop do as you think best.

 

I connected two identical blowers in parallel for a more powerful dust collector system. Based on my experience and a considerable amount of reading prior to starting the project, I provide my thoughts--most of which echo those comments from above:

1. Connecting two identical DC units is easy--a wye branch at the beginning of the run. In my case each DC had a 5" input port, and with an adaptor ran into a 6" wye (6" ducting run around the shop).

2. With non-identical units, bondo has the only workable solution. DC with different power ratings and port sizes cannot be usefully connected together, don't bother.

3. A single large blower is better than two smaller units. That is, a single 2-HP blower will outperform two 1-HP units hooked together. This is because of fan laws, impeller and port sizes, and there is no escaping this reality.

4. Because of #3 the only reason to connect two blowers together is because you own them. Cost is a mighty important reason, and advice to spend more money and buy something better is frequently given but not always easy to implement.

5. Two DC's means you need to power two blowers, turn them on and off, empty their dust bags, and take up more room in your shop. If hooked together, then you can use a single ducting system, which is what I did.

I recently (pre-Covid) saw a new 5-HP dust collector system for sale for a bit over $1,000. That would vastly outperform my two 2-HP system, and would be extremely easy to hook up. I nearly pulled the trigger on that purchase, but realized that the time and effort and money spent would be completely wasted because my 4-HP system is strong enough. It's the actual hood/shroud dust collection design at each machine that is limiting the system effectiveness, not HP or CFM or static pressure.

 

Thank you Sark for the information. I have 2 Wen DCs with 660CFM each. One I purchased and the other Wen sent when I had an issue with the first. Lucky for me it was just a circuit breaker issue and now I have two usable DCs. It will take a while but I am going to place them in a similar fashion as what you did and post the pics then. Thanks to your pics, some other questions I had were answered.

 

Adding to an old thread as some very important details have not been mentioned. First, what tools are you trying to use a dust collector on? Understand dust collectors are high volume but very low vacuum. They work for things like jointers, planers, and sort of on things like table saws. They are useless for anything with a small port or restrictions like hand held tools, even my spindle sander. Forget it trying to use one for a miter saw. 4 inches of vacuum won't pull squat through a 30mm hose regardless of the potential volume it can do. The other end is the shop vac/dust extractor end. Very high vacuum, like 90 inches, but very very low VOLUME like 150 CFM. They work on those restricted tools like hand held ROS. Nothing really works on a miter saw. my 5 HP dust collector can pull over 1700 CFM in free air, but only with very low lift like 3 to 4 inches of water. A couple sharp bends and it drops in half. At my TS input, I flow about 1100 CFM. At the throat plate, I can't feel any flow.

So, before asking how to modify, understand your need. A 3 inch pipe is marginally large to maintain sufficient FPM to prevent dropout. Chips need more than dust. Thins is why vac based systems usually run 2 1/2 lines and tools down to 20 or 30mm hoses. Larger pipe only makes the problem worse. Now on the big dust collectors. the slightest restriction kills their performance totally, so we use as large a line as we can keep airflow, long radius bends, minimal flex hose etc.

So we get to the OPs question. It provides NO more lift so tools with a smaller port than the vac will see no difference as the single is already pulling all it will for the pressure difference. Vacs typically are 2 1/2, so if you connect it to a 4 inch port, well you still only have what flows in the 2 1/2. If a 30mmport, you still only get what the vac lift will suck through. Now if you use a larger run, like a 4 inch, then you will increase the VOLUME from that tool.

As far as powering two vacs, one can run a 220 and split phases or just be sure they are plugged into different phases.
If you have two and one not on, you need a back-flow damper to prevent sucking through it. Only use similar rated vacuums.

Unfortunately this subject is actually a rather complicated engineering problem. Design, equations, testing. A lot of intuition is wrong and most of what is sold is equally wrong. Worst of all and I can't believe the CPSC allows it, dust collectors with only a bag filter so the fine dust that is what KILLS you is power fed into the air. One of these days the manufactures will get sued by someone with emphysema and they will wise up.

To the comment of emptying more than one bucket, well with cyclones, 99% of the dust is in that bucket. I went 4 years between changing the bag in my Fein vac.

The only company that may be on the right track for a single system for a one man shop is Record Power, but they have several issues overlooked that need to be resolved. I think it was the Oneida WEB that hinted at multi small cyclones with multiple vacs working as one system. Oneida sells a "high lift" system, but it is only high compared to a standard cyclone. No where near a dust extractor.

For the budget constrains, the largest Ridgid vac pulls more than any of the boutique dust extractors. A pair of them, a pair of Dust Devil cyclones, and exhaust outside so you don't need a HEPA filter, hook to a merged 4 inch PVC duct system may be just enough to deal with all small shop needs except maybe a big dust hood over a lathe for sanding. If using a restricted tool, you only need one vac on. Either use blast gates or a flapper valve on the output to prevent backflow.

If you are confused, than that is a great first step because it is complicated.

 

Interesting comments but I am confused.The Oneida Supercell list max vac at 100" and the Festool extractor shows max vac at 96". I think the Oneida Super cell is very similar to a dust extractor.

 

Deleted

 

Trvgeek, thanks for reviving this old thread. It was so long since I posted, I forgot I was the OP. So I answered my own question and then deleted it, lol.

My experience of using my two-in-parallel dust-collector system is that it works great, but doesn’t collect enough dust. The problem lies not in power, duct size or vacuum pressures but in the capability of the individual tool to direct dust to the duct.

We’re talking about internal baffles, hoods or shrouds. Here’s some quick examples:

Drill press: Has no dust-collection capability whatsoever. You must design your own.

Tablesaw: I have SawStop. Great on under-the-table dust (almost 100%) but bad on above table dust thrown by the the blade. I’ve used both the included (and much maligned) blade guard and the expensive overarm SS hood. They work about the same, which is to say not well. Easily capture dust when cutting a wide piece in the middle, but none capture the dust on an edge trim cut. And a lot of cutting is edge trim.

Sliding miter: Tons of YouTube videos on how to build a hood (or modify the delivered dust port) that works. They can work perfectly for a narrow piece at 90 degrees. But a 45 degree cut on an 8” wide piece? Forget it.

Band Saws: Some great videos on how to change the internal baffles, wipers, ports to actually get an efficient dust-collection system.

Belt Sander: I have a Jet 48” belt sander with 4” port. The 4” port immediately goes into like a 1 1/2” port. There are huge gaps between the sanding surfaces and the internal baffles. Lots of dust thrown into the air. What a joke! Of course, it’s vastly better than nothing, but really, how could you call that a design?

My conclusion is that your dust collector is fine, but designing or modifying your tool to have its dust collected is equally or perhaps more important.