2 Stage DC

[ssmith1627]

Something I just read mentioned that with a 1 stage DC that everything moving through the D.C. would impact the impeller itself. That doesn't sound like a very good setup. Is that actually the case ? I don't have one yet to look at but I can't imagine every wood chip flying up through there would hit it -- or even worse, whatever I might send up a floor sweep in the corner if I were to install one. Is this really a concern ?

How effective are these trash can lid attachments ? How many of you guys are using them ? I saw one in place at the local Woodcraft here so thought that was a good sign -- they said they use it all the time with their dust collector.

Just another piece to the DC puzzle as I try to get all this straight in my head. As always, thanks for kicking it around with me.

Steve

[Tom Miller]

I used to have a trash can separator in my DC setup. When I upgraded from a 1HP unit to a Grizzly 2HP, the can was undersized, and was scoured clean of all but the big chunks that would make an amazing racket spinning around the bottom at break-neck speeds.

I didn't want to make room for a bigger can, or waste any pressure drop, so I pulled it from the system. The impellers are pretty tough, and I'm sure can easily withstand even the odd 1" chunks that occasionally come through. (That tends to happen more when the 6 yr old is in the shop. )

Also, I didn't find it any easier to empty, especially now that I use a plastic bag on the bottom of my DC.

Regards,
Tom

[bigsteel15]

I have both sizes of the Lee Valley "trash can covers"
The small one fits the Shop Vac and a standard trash can...works great and I will probably still use it on my CMS and portable requirements.
The bigger one fits a trash can as well, but fits much better on a 45 G drum. I got a free one from a local scap yard. It works extremly well with the 4" connections connected to my 1 HP Delta DC.
I have a corner behind the door and under a cabinet that both sit in and they just take up wasted space.
Very little ends up in my DC bag.
I didn't like the sound the odd nail or screw made hititng the blade of the DC.

[Knottscott]

Without the 2nd stage to intercept larger chunks, everything does indeed go through the impeller. As Tom points out they are pretty tough though, but there's always some possibility it could get damaged. Another downside to having only a single stage is that some larger sliver chips can perforate plastic bags. I've using a 30 gallon trash can separator for a few years with good success.

[LCHIEN]

I agree with Tom Miller's reply. The trash can type seps don't work well with a big DC.

The impellors are steel, smaller bits of wood or even an ocassional nail or screw should not damage them but they do make quite a bit of racket when the hit, they are going several hundred feet per minute, maybe 50-60 mph. Scary things are larger cutoffs that fall in the table saw - good excuse to use a ZCTP. I have tried to cut some small dowel sections and had those fall in - whoa.

OK, the real 2-stage DCs are the cyclones, where the air is pulled thru the cyclone (1st stage) and the heavy/big chunks fall out the bottom of the cyclone into a can and the light, small particles pass by the impellor and are caught by a pleated cartridge filter (2nd stage) as the air blow out.


in this penn state cyclone the dusty air comes in the left, swirls around the tapered cyclone, the lighter particles get sucked up through the center and out the top where the impellor is sucking on the cyclone and blowing out to the right to the air filter stack. The air blows out thru the filter walls and the dust particles get stopped by the fine pores in the filter ( can be a cloth bag or a pleated paper filter) and drop down to the bottom. Note the can at the bottom of the cyclone for the coarse stuff and the can at the bottom of the filters for the fines.

[bigsteel15]

I also agree with both Tom and Loring, but we don't all have the space or budget for that type of set-up.
When I hooked up the 45 G drum with lid, I ran my saw cutting all the parts for my portable BT cabinet of 3/4" ply.
The amount of dust in the DC bag was maybe equal to 1 gallon. The drum was probably 1/4 full. This included jointing and planing some maple and birch trim boards.

[maxparot]

I have the HF 2hp DC w/ a Wynn canister filter. I also use a trash can separator inline to drop out the heavier particles. I find the trash can useful as long as it is emptied when it is less than 1/3rd full. A taller can of the same diameter would be great to increase capacity but as of yet I haven't come by one.

[DonHo]

From another point of view, I have a small shop and I use the GMC closeout DC from Lowes(claims 450 CFM). I upgraded the 30 micron bag to the 1 micron from Grizzly which really help with dust in the air but the CFM degraded pretty fast as the bag filled up. When I moved into my new shop I built a frame that has a 30 gal trashcan with seprator lid from Woodcraft on bottom and the DC sitting on top. I think it works great, the saw dust and chips endup in the can and not in the bag so performance doesn't degrade and the can holds lots more dust before having to be emptied. I'm very happy with the trashcan lid seprator.
DonHo

[Pappy]

Don't like emptying the DC bag more than I have to.

[ddamoore]

This fella makes a cyclone separator that you can incorporate with your existing DC. It is availble on Ebay. Though a bit pricey, it is cheaper than a full blown cyclone.

http://cgi.ebay.com/Cyclone-Separator-for-Dust-Collector_W0QQitemZ270010908018QQihZ017QQcategoryZ11704QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[stlmacgeek]

So, does anyone here have one of these ebay cyclones? If so, how well does it work? And is shipping included in his price? I couldn't tell from the ad.

thanks,
Kevin

This fella makes a cyclone separator that you can incorporate with your existing DC. It is availble on Ebay. Though a bit pricey, it is cheaper than a full blown cyclone.

http://cgi.ebay.com/Cyclone-Separator-for-Dust-Collector_W0QQitemZ270010908018QQihZ017QQcategoryZ11704QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[LCHIEN]

So, does anyone here have one of these ebay cyclones? If so, how well does it work? And is shipping included in his price? I couldn't tell from the ad.

thanks,
Kevin

My main concern about these is what the restriction-induced drop in airflow would be when you added that thing. If you look at the PSI catalog you'll see that the HP for the 2-stage units starts where the one-stage units stop. That sort of tells me if you add a aftermarket cyclone to an existing one-stage unit you won't have enough power, but I'm guessing with my engineer's hat on.

Also the stock 2-stage units have the impellor in the top of the cyclone which saves another source of restriction - the add'l hose.

[Tom Miller]

And, to take Loring's comments one step further, cyclones tend to have a commensurately larger impeller, too; say 14" diameter (compared to 12" for a 2HP single stage).

Regards,
Tom

[ddamoore]

My main concern about these is what the restriction-induced drop in airflow would be when you added that thing. If you look at the PSI catalog you'll see that the HP for the 2-stage units starts where the one-stage units stop. That sort of tells me if you add a aftermarket cyclone to an existing one-stage unit you won't have enough power, but I'm guessing with my engineer's hat on.

Also the stock 2-stage units have the impellor in the top of the cyclone which saves another source of restriction - the add'l hose.

Loring & Tom, as a follow-up question; are you guessing that the use of the cyclone separator has a larger drop in air-flow than the use of other separators, such as the trash can ones?

[MilDoc]

Always an interesting discussion. I have a HF 2HP unit with Wynn filter. I have yet to have any large pieces hit the impeller from a TS, BS, planer, jointer, OSS. But then, when using th planer / jointer, I take very slim passes. And I don't use the DC to sweep the floor. The only thing I collect is sawdust and thin wood shavings. Yeah, I have to empty the bag, but since I don't have room in a 1-car garage for much else, I have yet to see the need for a 2-stage collector.