Dual Separators?

[bbharat]

Phil, First off, thank you for the simple but extremely effective design. I have been using your baffle on a HF DC with a Wynn cannister for over a year and have been extremely pleased with the results. Before the baffle, I remember it took me almost an hour to remove the cakes out of the Filter. Now all i do is do some light cleaning with pressured air and the little that get to the filter are gone. No more cakes.

I recently decided to upgrade to a Grizzly 2HP, 12" impeller dust collector (the HFDC was only 9" impeller) and am rethinking the dust collection design overall.  I am also planning to get a new Wynn filter as the old one is over 2 years old and running it for over a year without the Thien Baffle, has probably decreased its effectiveness. I love the baffle, however dont like the fact that all the chips go through the impeller and want to build a true cyclone without all the sheet metal work or cost... . So here are my choices to avoid

1) Build a separate Thrash can separator. then connect to the Grizzly DC as is 
2) Build a separate Thrash can separator, then connect to the Grizzly DC with a Thien Baffle inside

Anyone tried the two separators concept and is yes, do you have feedback. How adversely does it affect airflow?

I have been reading about the Oneida Super Dust Deputy. Anyone know how that compares to the 1/2 separators options above? It costs $300 which i dont have.

Thanks

[phil (admin)]

Lots of people add a baffle to their DC and also build a second separator.  I know of several shops where the separator is installed in front of the big chip producers (jointer, planer) and the table saw, bandsaw, etc. (finer dust generators) bypass the separator and go directly to the DC (with baffle).  That seems like a good compromise to me.

As far as whether a separator in front of a DC outfitted with a baffle makes sense, well, I guess it depends on all the other variables.  Like the size of the ductwork, lengths of the runs, etc.

[bbharat]

Phil, Thanks. I will probably end up building the dual separator soon. First i need to build the baffle for my new DC, so i can get back working. I did notice an interesting approach on this page and wanted to get feedback on this as i cant seem to find a link to the owner http://webpages.charter.net/harkerhome/WWShop/dccanister.html

See image below. It does tie in interesting concept from cyclones and kind of makes it somewhat more difficult for dust to find its way to the filter without having a chance to settle down in the bag. I am thinking of incorporating it into the baffle design which i know works very well. So if I add a 8" pipe through the center of baffle, is there an advantage?
Does it help hurt the performance of the baffle and has anyone tried it out?

[phil (admin)]

Adding that pipe would be the equiv. of extending the outlet tube on my design about six-eight inches into the bucket, and ditching the baffle.  And we already know how that works (once there is any amount of dust in the bottom, it churns like crazy and lifts into the filter).

[bbharat]

Great. So i will avoid that and go with the same design i had on the HF DC  on my Grizzly and create a separate trashcan preseparator. Thanks for the prompt responses.

[bbharat]

I built the baffle and fitted it inside the Grizzly. The Grizzly 2HP is definitely a lot more powerful than the HF DC which is also 2HP, but given the 12" impeller it moves a lot more air than the 9" on HF.

I do notice an issue though. In the HF DC i was able to see the dust chips follow a cyclone pattern in the bottom bag and settle nicely.
However in the Grizzly i am not abe to see the cyclone effect. I also notice that not much shows up in the bottom bag either. As soon as i turn it on the bag fills up with air and thats it.

This time i have been particularly careful in keeping the difference between the two circles to 1.125" whereas in the HFDC it was more like 1.5". Is it because of this? Do i need to increase the difference between the two radii to compensate for the increased airflow?

[phil (admin)]

Interesting.  I know of lots of users on Griz 2-HP machines that haven't had any problem like you're describing.  Have any pics?

[bbharat]

I emptied what was in the bag and sucked it up again. The baffle is made out of walnut ply that i reused from another project. The line that you see is a dado and is only on the bottom side. It is attached at 2 locations on the 120 side and one on the 240 side

From what i can tell it is either that the grizz is lot more powerful so i cant see the swirl action with little saw dust like from a table saw(can see when it sucks up a lot) or i am doing something wrong. Maybe there is a third... You can see a video here http://picasaweb.google.com/lh/photo/TbHPxzCXAe7d5eD2ukR_OA?feat=directlink

Would love your thoughts.

[phil (admin)]

Are you using a bag on top, or a cart. filter?  The pics you've included seem to show debris in the bottom bag, and you said not much is getting to the bottom bag.  So I take it the rest is going to the top bag/filter?  Can I see pics of that?

Lots of people doing the baffle on 2-HP units, it works no problem.  Something else must be amiss.

[bbharat]

I am using a wynn filter on top and a plastic bag bottom. Yes, i probably was wrong. I thought not much is going in to the bag when i used the DC on a table saw and because of the air circulating in the plastic bag.

When i pulled everything out of the bag and sucked it up again, most did end up in the bag. I plan to do use the planer and jointer in the next couple of weeks. When i get close to 3/4 full in the plastic bag, will empty and look at the filter to see if there is a difference between the HF DC and Grizz on the filter. Will keep you posted.