Another dust collection post

[Jeffrey Schronce]

Do you have an outside window? It has been suggested here and I would not underestimate the power of a powerful fan pulling the air outside. I honestly think I get more mileage from that than the 100lb Delta air cleaner hanging over head.
I have a powerful Ridgid vac that I used prior to getting my DC. I think with the right filters, sound muffler, etc that this would be a huge improvement for you. Remember, the fine dust is what you are worried about. Whatever you do focus on the fine dust.
I know others are going to disagree, but that work area is awefully small to start running DC hose everywhere and accounting for footprint of the DC it will take a lot of room. I think a well tricked out vac is going to perform nearly as well as a average, economy DC. And with the price of shop vacs lately, you could put one in the router table, have one for TS, etc.
As far as hand routing, how about doing the routing on a downdraft table? I just got a downdraft table and have been doing hand routing on it with huge success.
I don't know what your budget is but there is always Festool.

[drumpriest]

I have the DC650 canister version and like it. I also have a double fan in the window blowing the ambient stuff out, and a box fan (20") with a furnace filter for local cleaning. All of this plus a dust mask makes for a fairly clean shop.

[vaking]

DWK,
No my pre-separator is not a cyclone. Cyclone lids seem to work work better with shopvacs. Shopvac is a device with small airflow but high air pressure. Dust collector has higher flow but less pressure. Small dust collector in combination with cyclone lid is a bad idea as you will have not enough pressure. There was a string here about it somewhere.
My separator is using a filter mesh - I posted some pictures below:
http://www.bt3central.com/showthread...dust+separator.
Works well because it does not lose pressure.

[jonathan55]

that's pretty "porous" - lets a lot of fine dust back into the room
you really want to upgrade the bags on this to something like 1 micron or 2 mircon at worst.

Is it possible to find 1 micron bags for this unit?

[ssmith1627]

Just an idea as I try to plan out getting a DC set up in my own garage/shop.

What if you put the whole dang D.C. unit outside. I wouldn't be as worried about replacing the stock bag if it were just venting to outside anyway. The fine particles that escape will just be blown away. I have a window on the west wall of my garage and I could build something to seal it up with it just open enough to let that 4" hose come in. My house sits back from the road and my garage faces sideways so that puts that window on the back of the house where you wouldn't see it. I'd have to build some type of basic enclosure for it there to keep it safe as well as keep it protected. It'd save me a good bit of space, cut down on the noise and the air contamination at the same time. From inside the window, I can go up to the ceiling and across to my BT, my router table and a floor sweep.

Anyone see an issue with doing that ?

Steve

[JR]

Just an idea as I try to plan out getting a DC set up in my own garage/shop.

Anyone see an issue with doing that ?

I think it's a pretty good idea for all the reasons you mentioned. One issue, frequently mentioned, is that the air in your shop will be moved outside throught the DC and into the atmosphere. If you've got AC or heat you want to keep inside that could be a problem.

JR

[ssmith1627]

Very good point. Thanks. Wasn't thinking of that. When I get to that point, I might have to place it out there temporarily over a weekend and try it out to see what effect it's really having before making a permanent place for it there.

Steve

[radhak]

how about a DC from HF?

till now i have been dependent on my shopvac to clean up after the fact, so 'dust collection' in real terms has been absent. but am worried enough about long term effects to consider it. the 'frankenvac' by phil seems pretty neat and a big jump up for what i have currently. but i have tiny router table benchtop, not on TS (as i own the BTS20R, not the BT3100), and a small belt sander that i use on the floor or on my workbench, so am anticipating quite a bit of setup each time i use any of these tools TS, Router, Sander. (don't have any jointer/planer).

i also saw this DC at HF for $179. any opinions if this would be a good buy?
http://www.harborfreight.com/cpi/cta...238&pricetype=

while there i also saw they have a 'portable' DC for $119 which is very tempting, particularly because Jet's portable seems to be discontinued.

- radhak

[LCHIEN]

till now i have been dependent on my shopvac to clean up after the fact, so 'dust collection' in real terms has been absent. but am worried enough about long term effects to consider it. the 'frankenvac' by phil seems pretty neat and a big jump up for what i have currently. but i have tiny router table benchtop, not on TS (as i own the BTS20R, not the BT3100), and a small belt sander that i use on the floor or on my workbench, so am anticipating quite a bit of setup each time i use any of these tools TS, Router, Sander. (don't have any jointer/planer).

i also saw this DC at HF for $179. any opinions if this would be a good buy?
http://www.harborfreight.com/cpi/cta...238&pricetype=

while there i also saw they have a 'portable' DC for $119 which is very tempting, particularly because Jet's portable seems to be discontinued.

- radhak

A large number of people on BT3 central and elsewhere have what is called the "HF 2HP DC" due to its relatively high value per buck. It has leaky 30 micron bags which should be replaced ASAP.
There's tons of messages about it here mostly in thetool section also maybe getting started. Very hard to search for because the forum search software ignores 2- and 3-letter words/acronyms. But just browse thru those sections for the last year or so.

I have one i have upgraded with grizzly cannister (2-micron pleated filter) and a plastic catch bag. This has the advantages of very large filter surface area for low restriction and fine filtering, and a visible catch bag which is tie-up and toss rather than emptying and resuing a cloth bag (imagine the mess!).

The cons of the HF 2HP DC is
- poor instructions, some parts have changed and its confusing
- a few motor and switch problems reported but HF is generally good about taking back and replaceing, just not convenient
- over-rated (at 1600 CFM), it's more comparable in motor current and vane specs to 1.5 HP DCs from other manufacturers of similar size so it's more likely comparable to the 1200 cfm claims of those DCs which they in turn generally can't be depended upon for but around 800-1000 cfm in real life use. It's notorioulsy hard to measure these things.

[bigsteel15]

It's notorioulsy hard to measure these things.

HMMM.
I have a capsuhelic gage (need to check the range).
If I drill an orifice of a pre-determined size and measure the pressure drop across it, is there a formula to figure the CFM, or do I need an instrument to determine another variable such as velocity?
I have a handheld wind speed indicator.

[JR]

I have a handheld wind speed indicator.

The mind boggles as to what you could do with that after a few beers on a fishing trip!

[LCHIEN]

HMMM.
I have a capsuhelic gage (need to check the range).
If I drill an orifice of a pre-determined size and measure the pressure drop across it, is there a formula to figure the CFM, or do I need an instrument to determine another variable such as velocity?
I have a handheld wind speed indicator.

the usual way to measure these things is to use a differential pressure gauge and a pitot tube. A pitot tube is a small double tube that has an opening that faces into the airflow (thus measuring dynamic pressure). and a second opening for the second tube that faces away from the airflow and thus measuring static pressure.
The difference indicates the wind velocity and indeed this is how airplanes measure airspeed. If you ever get a close-up look at a private aircraft you'll see near the nose a little bent pipe sometimes reinforced with a fin, pointing ahead.

http://www.allaboutall.info/images/t...be_diagram.png


This just gets you airspeed at the point of the end of the pitot tube. If you assume the airspeed is ideally uniform across the whole duct (where you would mount said pitot tube on the inside) then you could calculate the volume air flow (CFMs) as the velocity times the cross section area.

BUT (big but here) the airspeed is not uniform; it usually falls parabolically to near zero at the edges where the drag is and is maximum only at the center. Further more, they tell you that there are eddies, swirling air in a duct, that have big differences from the average, due to any protuberences in the duct, e.g gates, turns, fittings, Wyes, orifices, etc. In order for the airstream to be smooth enough to accept the velocity at the pitot tube as average, then you are expected to have 20 duct diameters of smooth-wall tubing before and after the pitot tube. That works out to about 15 feet of straight shot tubing which will also affect the airflow by adding extra restriction of its own.

I have a magnehelic differential gauge and some cheap pitot tubes; I just did not have much luck and had no way of verifying the numbers I did get. Believe me, its very frustrating.