dust collection or vacum

[dale137]

Hi, I have a rockler vacuum system with 60 ft of clear 2 1/2 tubing and about 5 blast gates. I currently have a Rigid 6.5 hp vacuum. Would a 3/4 hp dust collector that is used for woodworking have more suction? The vacuum is ok, but not outstanding. A sales guy at Rockler told me his dust collector would outperform the rigid vac. And i don't always believe the statistics they post.
Anyone have any experiences? thanks

 

[Gore]

I was looking at something similar to what you're referring to and the vacs had something like 500cfm...and dust collectors were like 1500cfm...no comparison. I might be a bit off with the numbers...but the idea is accurate. True dust collectors have waaay more cfm than just about any consumer grade vac. What I found stopped me from looking for a new/bigger vac.

 

[derosa]

I was looking at something similar to what you're referring to and the vacs had something like 500cfm...and dust collectors were like 1500cfm...no comparison. I might be a bit off with the numbers...but the idea is accurate. True dust collectors have waaay more cfm than just about any consumer grade vac. What I found stopped me from looking for a new/bigger vac.

Numbers have to be checked closely and it takes money to get 1500cfm.

Most 1-1.5hp dust collectors are only moving 500-650cfm and even then it can be about how everything connects; length of runs, filter quality, how accurate the HP rating is. The HF dust collector comes highly recommended on a lot of woodworking sites as a good place to start with the caveat that you really need to upgrade the filter to something a lot better. Mine has been upgraded to a much finer filter but still a bag filter and as such it is still inadequate, a pleated filter will help it **** better and filter better.

In my experience dust collectors have 3 major upsides and several downsides as a hobbyist.
1. They can really hold a lot of sawdust; for general futzing around it can weeks to fill and with the clear bottom bag its easy to see how full it is. I did manage to fill it in less then 2 hours once but I was running several hundred feet of custom moulding at the time.
2. They're a lot quieter, I have a 6.5hp ridgid that has a noise reduction feature and the dust collector is quieter.
3. The motor is designed to run a lot longer without overheating. I get a wife/kid/work free rainy day and I can have the dust collector running for 4-5 hours straight. Haven't tested how long the ridgid can run but after half an hour it seems fairly warm.

However it is a lot cheaper (hundreds less) to add a hepa filter to a shop vac and with relatively cheap bags that are easier to dispose of that filter can stay clean for a long time.
A shop vac can also be easier to move from tool to tool unless you have runs for a built in dust collector system. While 650cfm is considered an adequate starting place for a system, if you have long runs and lots of flex hose it can quickly not be good enough. Personally I prefer a mix of both. I use the dust collector on the planer, bandsaw, and tablesaw. The dust collector is used to get the dust/woodchips from the drill press, radial arm saw which only has a 2.5" opening, the router table and to clean up under the jointer which is cheap and doesn't have a dust port. It also gets used on the second port of the bandsaw if I'm doing a lot of cutting.
Running a big dust collector, overhead runs, lots of drops and sizing it all is the best if you have money, otherwise a dust collector is great but both is better.

 

[guy48065]

That's a lot of small diameter tube and your drops are likely all spiral flex hose. These restrictions will kill your CFM on a DC that has high CFM volume but low static pressure. If you don't upsize the main trunk I think you may be better off with the high-static-pressure shopvac.

 

[Milton Shaw]

Shop vacuums have brush type motors and usually are rated for less than 300 hours total run time. Dust collectors have split phase or capacitor start motors and are rated for continuous duty, 1000's of hours. Dust collectors use a lot of cfm's to move dust along. Vacuums use a lot of suction not cfm's to move dust. Vacuums rating in suction is inches of water, normally less than 100, and cfm's also less than 100. Dust collectors are rated suction less than 25 and cfm's more than 250. Noise levels are much lower for dust collectors also but they can also use a muffler to quieten them down. For a system in a shop, a dust collector will be a lot easier to work with (noise,collection capacity etc.). For a system to take on a job a vacuum will be lot easier to use (one hose, one container etc). A commercial rated vacuum, like used by janitors will normally be a lot quieter than shop grade vacuums. I have a Clark commercial that is so quiet you don't need ear plugs, whereas my Ridgid shop vacuum is as loud as a router.

 

[SRSemenza]

Stats aside the simple difference is.......

DC = high volume / low velocity and vac is low volume / high velocity air movement.

In general vacs will perform better connected to hand held power tools or tools where the port is close to the dust source and can collect from a concentrated spot.

DC will perform better for broader area collection points , with less concentrated dust, and where moving lots of air will create a draft sucking dust in.

Doesn't mean there isn't some cross over but that can be a general guide.

You almost need both depending on the tools and work.

What tools are you collecting from?

Seth

 

[cgrutt]

What are you using it for? Large table saw, router station, planer, large bandsaw etc needs dust collector. Handheld Sanders, routers, portable TS etc vacuum might do. 3/4 HP for dust collector seems small as does 2.5" hose. I think Oneida Air makes a Dust Deputy (or similar name) that works with standard shopvac but gives some benefits (cyclone drop) of larger Dust Collection system.

 

[dale137]

thanks everyone for your responses,,,it helps me make the decision. I have the system set up with the drops, for simple vacuuming of interiors, and a sand blasting cabinet so far. Possibly going to add on as time goes. As some of you have pointed out the rigid is loud,,and it does ****,,,but when I am cleaning off piles of debris, metal shavings etc, it takes awhile. Thanks afain,,time to start shopping.

 

[guy48065]

Ummm...don't even THINK about sucking up metal shavings and chunks with a DUST collector. Solids can bend or break the impeller blades and if the impeller is steel sparks can be generated that can ignite the dust in the bag.
Use an in-line separator drum to catch the chunks before they pass thru the impeller and empty it often if you're sucking up both metal & wood dust.

 

[rlitman]

Numbers have to be checked closely and it takes money to get 1500cfm.

Most 1-1.5hp dust collectors are only moving 500-650cfm and even then it can be about how everything connects;...

Yes. Let's start with this. On a 4" diameter duct dust collector, don't expect to get more than 500CFM at the very most, no matter how much power you put into it.

The OP is asking about suction. This is a difficult question, as both CFM and "lift" come into play, but when it comes to dust collection, the actual CFM is usually the most important value.

 

[guy48065]

Yes. Let's start with this. On a 4" diameter duct dust collector, don't expect to get more than 500CFM at the very most, no matter how much power you put into it.

The OP is asking about suction. This is a difficult question, as both CFM and "lift" come into play, but when it comes to dust collection, the actual CFM is usually the most important value.

I was going to dispute your numbers based on my experience with my system that uses 4" thin wall PVC main trunks. I went and got my notes and I find that you're actually correct.
A few years ago I brought home three different air velocity meters that use different sensing technologies and tested my own DC system. I found that my 3hp Cincinnati Fan 2-stage DC flows 390 CFM at the open Inlet, bushed to 4", with an aftermarket 3-micron bag on the outlet (650 no bag). If memory is correct this is an 1100CFM-rated fan.
My drops are all 3 inch thin wall PVC with a gate on each one. At my table saw I read only 220 CFM. This might seem terrible but it works and I never have any blockages. I use the same floor port (pipes were laid before shop floor was poured) when I use my 12 inch planer or my 6 inch jointer and the long shavings never plug up the lines.

My full-shop system was very inexpensive to build and by any textbook that you care to read it is a poor layout, and uses parts that nobody would recommend (PVC). It performs great. I don't think there needs to be so much emphasis on high flow numbers unless you start talking about warehouse-size operations.

 

[Toolfool]

If you want to fully understand dust collection read : http://billpentz.com/woodworking/cyclone/ . Systems running low CFM and narrow piping (4") are 'chip' collecting, and are missing the fine airborne dust which is what will cause health issues.

 

[outdoorspace]

Hi, I have chosen a vacuum system for myself. I would not like to drag the vacuum cleaner all the time, and this is a plus of the vacuum system. I would not trust the sellers from the store, because often they are not competent enough. When I chose the vacuum system, I looked at all the information at https://cleanersexpert.com/best-garage-wall-mounted-vacuum-system/. There is a clear explanation on this site why a vacuum system will be better and more convenient than a regular vacuum cleaner.

 

[Unruh]

I had a dust collection system that I got from Harbor Freight. It moved a ton of air, but when the air is restricted (many of my tools only have a 2 1/2 ports), the air movement was cut drastically. My garage is not very big and the ceiling isn’t very high, I didn’t want to run 6” or 4” pipes all over. I changed over to a vacuum with a Thein baffle for the dust. I’ve had very good success with it.

 

[dledinger]

Shop vacs make poor dust collectors. The volume of air moved by a true dust collection is what makes it work. The “filter bags” you see on the cheap models are garbage. You need an actual pleated filter to have anything that works for more then a few minutes. Also, a battle to keep the dust in the collection bag and out of the filter, is a necessity.