Big tools and dust collection

[woodbutcher]

I have had a hard time wrapping my head around why horsepower is such a concern with dust collection, but have realized its because with more horsepower, comes a larger impeller and housing, which moves more air. Am i right about that?

[Tom King]

exactly

[Bankstick]

Would love to have a DC but I'm too cramped for space.  The truck is a great idea.  Fill it up and take a drive in the country.  Knew a guy who did this with his leaves every fall.  Fill the truck, cover the bed until he got out into the sticks, uncover it and drive home with the tailgate down.

[Tpt life]

Chips need pressure to lift. Fines need volume to clear. It needs to be understood that way. If all you have is pressure, the fines will easily escape the draw. 

[gee-dub]

3 hours ago, woodbutcher said:

I have had a hard time wrapping my head around why horsepower is such a concern with dust collection, but have realized its because with more horsepower, comes a larger impeller and housing, which moves more air. Am i right about that?

Pretty much.  A larger impeller and the requirement to move more air mass takes more power.  Remember the demonstrations in Elementary school or watching Mr. Wizard . . . a balloon full of air weighs more than an empty one.

[wtnhighlander]

I heard a good point made by Kyle Toth, regarding the big DC in his shop. Having a single, large unit discourages frequent stops & starts, but leaving it running constantly has a noticable impact on the electric bill. As he is about to set up a new shop, he plans to use multiple smaller units.

[mat60]

6 minutes ago, wtnhighlander said:

I heard a good point made by Kyle Toth, regarding the big DC in his shop. Having a single, large unit discourages frequent stops & starts, but leaving it running constantly has a noticable impact on the electric bill. As he is about to set up a new shop, he plans to use multiple smaller units.

Funny you said this. I have two 1hp units. One at the table saw and one at the jointer.  I save the 3hp for everything else.  I would not want to turn the 3hp off and on all day and i also feel Kyle makes a good point.

[Pondhockey]

6 hours ago, C Shaffer said:

Chips need pressure to lift. Fines need volume to clear. It needs to be understood that way. If all you have is pressure, the fines will easily escape the draw. 

The funny (not ha ha) thing is that the chips are what you see and fill up the canisters; removing them helps to clean the shop, but it's the fines, which generally you do not see, that are the health hazard.

Also, as someone pointed out, it makes sense to think about what machines generate fines.  Mostly it's the sanders, then the saws (at least that's my impression.)  I sand outside with a mask (and vacuum).  I have considerable trouble collect the debris from the saws.  (Again, I wear a mask.)

[Eric.]

13 hours ago, wtnhighlander said:

I heard a good point made by Kyle Toth, regarding the big DC in his shop. Having a single, large unit discourages frequent stops & starts, but leaving it running constantly has a noticable impact on the electric bill. As he is about to set up a new shop, he plans to use multiple smaller units.

 

12 hours ago, mat60 said:

Funny you said this. I have two 1hp units. One at the table saw and one at the jointer.  I save the 3hp for everything else.  I would not want to turn the 3hp off and on all day and i also feel Kyle makes a good point.

 

Meh, first of all the cost of running the DC is negligible in the context of the ridiculous cost of woodworking - it's kind of like complaining about the cost of glue.  And second, the cost savings running a smaller DC vs. a bigger DC is probably pennies per hour.  Losing precious shop space and the inconvenience of maintaining multiple DCs sounds like a pretty big sacrifice to maybe save ten or twenty bucks over the course of a year (even if it's a hundred bucks a year it's still not worth it).  Not to mention the smaller units will likely be less efficient, even if they're hooked up to individual machines.  Sounds like a loser idea to me.

[Tom King]

The multiple machines to save on electricity makes no sense.   A hobbyist would never recoup the cost of the extra units, and if it's a business, the cost of electricity is negligible, or if it does matter, they need to be doing something else for a living anyway.

[Woodenskye]

The only way I could see running multiple DC as a benefit would be if you had an extremely large shop and over a very long run the amount of air flow loss is significant.  The other would be if you had a separate room which you ran a CNC machine or some other specialized use.  

[mat60]

6 hours ago, Eric. said:

 

 

Meh, first of all the cost of running the DC is negligible in the context of the ridiculous cost of woodworking - it's kind of like complaining about the cost of glue.  And second, the cost savings running a smaller DC vs. a bigger DC is probably pennies per hour.  Losing precious shop space and the inconvenience of maintaining multiple DCs sounds like a pretty big sacrifice to maybe save ten or twenty bucks over the course of a year (even if it's a hundred bucks a year it's still not worth it).  Not to mention the smaller units will likely be less efficient, even if they're hooked up to individual machines.  Sounds like a loser idea to me.

Well the Meth is working good for me.  I had the two 1hp units way before my 3hp dc and didnt pay much for them and they work fine.   When I turn them off and on all day and when they go to hell Im not out much. They dont take up much room in my shop.   My 3hp works better with a shorter run of pipe.  As far as the cost of running the 1hp and the 3hp its the starting of the different size units that make a difference witch is why its best to leave a large unit running rather than turn it off and on. That goes for anything in the shop.   I all most forgot.  My 3hp vents outside with no bags so when Im working at my table saw and jointer I dont loose allot of heat and air cond and I can tell it makes a big difference.  So thats my loser idea Eric.

[Eric.]

Your situation is different.  You started out with a couple smaller units and added a bigger one.  It makes more sense to keep them and use them if you have them.

But to demote yourself from one large unit to several small units to save a few pennies on electricity doesn't make any sense at all.  There are valid reasons to have more than one DC but the electric bill is not one of them IMO.

[drzaius]

I have a 5HP collector & keeping the number of starts per hour to a minimum is not hard. I just let it run if it's going to be a few minutes until I need it again. It makes a great air cleaner when it's just sitting there running & it's quiet enough that it's not an annoyance. 

[woodbutcher]

1 hour ago, Mike. said:

A dust collector has to push all that air through a filter of some sort.  The better the filtration, the more power it will take to push the air through the filter.  Exhale.  See how easy that was.  Now go blow into a paper bag and keep blowing after it is full with air.  It is significantly more difficult. 

The real benefit of direct venting your fines, aside for cleaner air, is that a less powerful DC can move a lot of air if it does not have to push air through a fine filter.  

I really hope that someday when I have a dedicated shop that i can just vent outside. Filter maintenance does not sound fun to me, especially the giant filters I see on the big collectors. 

[drzaius]

47 minutes ago, woodbutcher said:

I really hope that someday when I have a dedicated shop that i can just vent outside. Filter maintenance does not sound fun to me, especially the giant filters I see on the big collectors. 

Filter maintenance, if there is a cyclone ahead of it, is pretty trivial. So little dust gets through to it. Unless you let the bin overflow, then there's nothing trivial about getting that mess cleaned out. Incredible how tightly the dust & shavings can pack in there.

[Tom King]

Even with a bagger, after you empty the bottom bags, and put them back on, just start it up, beat on the top bags with a flat stick, and anything caked inside the top bags falls down into the bottom ones.  Just like they say about dirt bike air filters: "dirt filters dirt", but it's another reason that more power is better for a DC, if dust is going to filter dust, which it will at some point.  

[Mick S]

On 8/29/2017 at 10:41 AM, Tom King said:

I don't wear a respirator, or have an air filter, because we don't really need either.  We also don't have to clean dust before we leave a museum house.

 

1 hour ago, Tom King said:

Even with a bagger, after you empty the bottom bags, and put them back on, just start it up, beat on the top bags with a flat stick, and anything caked inside the top bags falls down into the bottom ones.  

I don't mean to be argumentative, Tom, but these two statements don't add up. As others have stated, it's the fines that cause the health issues. I've used lots of different brands and models of single stage collectors and when you "beat on the top bags with a flat stick" it makes an unholy mess of the surrounding air - mainly the finest dust you've collected.

[wtnhighlander]

Must remember, Toth is in California, rates are higher than many parts of the U.S. And I have no idea how large his unit is. May be 100 hp, for all I know.

[Tom King]

1 hour ago, Mick S said:

 

I don't mean to be argumentative, Tom, but these two statements don't add up. As others have stated, it's the fines that cause the health issues. I've used lots of different brands and models of single stage collectors and when you "beat on the top bags with a flat stick" it makes an unholy mess of the surrounding air - mainly the finest dust you've collected.

The Woodtek bags don't do that.  I've used those since 2009, and don't remember having them off since I first put it together.  There is no fine dust on the outside of those bags, and there never has been.   The 2hp Gizzly that I have is awful.  Not only can I not beat on the bags, but they don't even filter everything visible to start with.  If I end up keeping that one for the big bandsaw, I'm either going to buy some Woodtek bags for it, or just let it blow outside.  It's almost not worth having it running with the bags that are on it.  Those Grizzly bags are thin, and have a built in belt with buckle for sealing.  The Woodtek bags are probably 1/4" thick, and have nice bands to completely seal them to the connectors that they are a tight fit on.

Here are the bags I like:   https://woodworker.com/dust-collector-1m-bag-12-1-2-x22-w-4-opening-mssu-123-851.asp?gclid=CjwKCAjwxJnNBRAMEiwA8X_-QSOUlJE6rBWPqxV9pIZJeZxR7IyDSzc_DSdD-zCtswpPFAkZZhqOihoC3QUQAvD_BwE  

I'd never put that Grizzly DC in a house.  It's in a separate building at home, and it's one of the few things I wish that I had never bought.

When we move the portable setup, every year or two, I take the bottom bags off, and push the top bags down through the connectors, so they get cleaned some by the air from being on the highway on the trailer.  I have noticed some caking then, but we might have moved before we beat on the bags with the machine running.  I expect some fine stuff stays attached to the inside, but it doesn't go through.  The slapping with a stick is just to drop the caking, and that probably drops a lot of the fines along with the caking.

I've seen guys beat on the really big bags in a millwork shop collector room, and some did go in the air, but not really that much, but they have dust on everything in the building also.  I have no idea what the fabric was like for those bags.

I really like the Woodtek bags.  They're really thick compared to anything else I've ever had in my hands.

There are a few things i wear a respirator for, and sometimes a supplied air hood, but not when running woodworking machines, except for the big bandsaw until I get a better DC going for it.  I'm 67, and can still breeze up a long flight of steps without getting out of breath, and I've been doing this stuff for a living for 44 years now.

[Eric.]

26 minutes ago, wtnhighlander said:

Must remember, Toth is in California, rates are higher than many parts of the U.S. And I have no idea how large his unit is. May be 100 hp, for all I know.

Maybe so...I just think sacrificing that much convenience for tiny scraps of electric savings is kind of silly.  The extra time it takes him to maintain three collectors instead of one probably costs him more than the extra pennies on the electric bill.  I won't argue about it because I couldn't possibly care less, but it's just illogical to me, that's all.  A single, high-performance collector makes a whole lot more sense.

[andrew-in-austin]

If you have the money, by all means, get the 3 or higher HP dust collector.  And if you don't, it's really hard to not get the HF 2HP unit.  It's not great, but it's much much better than a shop vac or nothing at all.  I think getting that dust collector is a right of passage for woodworking these days.  You'll never know how good your future 3 or 5HP dust collector is unless you had the entry level model...

[difalkner]

I bought the 2 HP from HF last year before finishing the CNC build and it does a good job of collecting dust and chips from every tool in the shop.  Our shop is our two-car garage but it is well equipped and full of tools (CNC, PM66 table saw, PM54a jointer, Laguna 14SUV, SuperMax 19-38 drum sander, old DeWalt 733, etc.).  I have a 20' clear hose that I move from tool to tool and a dedicated one for the CNC so I just switch them out at the DC rather than have gates.

But the big thing I noticed is all the dust around the DC because so much makes it out of the 5 micron bag.  So a couple of months ago I bought the Wynn 0.5 micron pleated filter and now there's no dust around the unit at all.  And because it has greater surface area than the old bag it now pulls harder than it did, even draws less amps on the motor. 

An additional benefit to not having fine dust on everything is that now I don't have to clean the filters on my mini-split unit every week like I did before.  Now I clean them once a month and they aren't as dirty in that interval as they were when I cleaned them every week.

My $0.02 is that 2 HP (or whatever it really is) is sufficient for my needs and all of my tools.

David

[rodger.]

Okay, let's dig a bit deeper into the DC world...

I have been looking to upgrade for a while, and have my eye on the Oneida mini gorilla. It's 1.5 hp, and pulls an actual 600 CFM (with filter and piping attached). The inlet and pipe is 5" diameter.

In my reading (BP), i am not confident this is enough for my largest tools (13" planer, 6" jointer). However, after reading other sources that are reliable (Oneida, etc) many say that it is enough to catch all the dust and fines.

I know there are a lot of smart people on here, so what is your opinion?

Collector will be moved tool to tool, and the stock length of pipe will be used.

[Cheeset202]

Depending how deep you want to go, you can read Bill Penz's dissertation on fine dust removal in a wood shop.  At the end of reading his dissertation you will learn the following:  you need a minimum of 5 hp with at least a 14" impeller, an efficient cyclone to separate shavings and fines into a collection bin and exhaust the micro particles (the unhealthy stuff) outside.  Your ducting design needs to be a minimum 7" trunk line and 6" at your machines.  According to Bill, anything less and you are exposed to micro dust.  I have been slowly working my way to this goal, not sure I will ever achieve it because it is expensive and a lot of work!  A good dust mask and a decent DC (2 hp) to collect shavings is a good start.  If you are going to use a filter canister or bag a cyclone separator (2 stage system) is necessary.