Mounting baffle inside a DC

[D Romano]

I finally got around to testing and photgraphing my dust collector with the baffle mounted inside. I did not do any extensive tests, but I was amazed at how well it has worked so far. First off, I have a Jet DC 1200 with a cartridge filter from Wynn Environmental. They sell 2 kinds and they refer to them as the 35A series. One is spun bond, the other paper blend. The paper blend as alot more square footage of filter area and is cheaper, but probably does not last as long. Anyway, it always clogs up with shavings when I use my jointer or planer. I installed a flapper, but once it's clogged, it's clogged and if I forget to use the flapper, it can get so bad that I can't even move it. I also had installed a neutral vane.

To install the baffle, I first mounted the lower bag into the separator ring. The Jet has a very nice snap-in plastic ring that makes installation almost foolproof. With the bag installed, I rested the baffle against it, checked for level and attached it with 4 screws. The baffle is made of 3/4" MDF. The difference between the diamters is about 1.25". The 3 screws are #10 round head, about 1" long, the 4th one 2" long. I'm not sure the 4th screw along the small diameter section is really necessay, it was mainly to keep it level and I wasn't sure how much force would be on it from the air movement and I did't want any surprises. Once the baffle was mounted, I realized that I needed a new way to mount the canister.

The first photo below shows the canister mounted on the DC. I now use 4 rubber straps to hold the canister in place. These work much nicer than the hooks supplied by Wynn, even if you don't use the baffle.

The second photo shows the baffle inside the separator ring. The baffle is attached at 4 points. 3 along the large diameter section and a 4th to support the middle of the small diameter section. Note how the wood chips have caught on the 4th screw. The center hole in the separator ring is about 9" diamter. In the area marked "Dead Zone" there is no airflow when the DC is running. The air spills out of the hole at a very shallow angle everywhere except here. I had decided to remove the neutral vane, and believe that while it may increase airflow by reducing turbulence, it probably is deflecting unseparated air up into the donut hole, helping to clog the canister filter.

Also notice that the donut is tapered, sloping down towards the center. This is essentially an outlet pipe, but because the air exits the hole at a shallow angle, when a a cansister is mounted on it with a much larger diameter, the air must be jamming into a wedge like space between under the canister. This must be decreasing airflow. This did not occur to me until this morning, but what I need here is an outlet pipe extending UP from the hole to the bottom of the canister.

The 3rd photo shows the mounted baffle from the underside. This shows the configuration the best. 

To test the effectiveness of the baffle, I did something that I thhought would normally clog the canister. Having previously milled alot of Ipe and then cleaned the pleats of the canister the best I could, the inside of the canister was clean and yellow in color. So I took a 1x6 pine board, 5 feet long and milled on the jointer from a thickness of 3/4" to only 3/16". It made alot of white shavings that should be very easy to see.

After milling the board, I carefully took off the canister expecting it to dump a bunch of sawdust on my shoes, but I was amazed that there was hardly a spec of pine sawdust in it! The 4th photo is shows the inside of the canister after the test.

The 5th  photo shows the baffle from underneath, where the collection bag snaps in place.

The last photo show the separator ring from the inside, looking at the inlet.

For me the biggest unknown at this point is how full the lower bag can be before scrubbing occurs. At some point, the bag must get full enough for the dust to be blown out and up into the filter. I think that should be the next test, because once a canister is clogged, it is very hard to get it clean. 


David

[phil (admin)]

For me the biggest unknown at this point is how full the lower bag can be before scrubbing occurs. At some point, the bag must get full enough for the dust to be blown out and up into the filter. I think that should be the next test, because once a canister is clogged, it is very hard to get it clean. 

David

Great work.  Fill 'er up and let us know.  You should be able to get pretty close to the bottom of the baffle.

And you planed down to 3/16?  Watch those fingers!   :o

Can't wait to read your next report.

[phil (admin)]

David,

Do you mind if I post some of your pics/write-up at other sites so people can check-out your success?  Many people have asked me about modding their 1-stage DC and some said they were going to, but nobody ever got back to me.  I think if people could see how well it worked for you they'd be inclinded to give it a shot on their own.

Thanks,
Phil

P.S. For now I'll paraphrase and point back here at a couple of sites.  But some don't allow that and I don't want to "lift" your work w/o your permission.

[D Romano]

David,

Do you mind if I post some of your pics/write-up at other sites so people can check-out your success?  Many people have asked me about modding their 1-stage DC and some said they were going to, but nobody ever got back to me.  I think if people could see how well it worked for you they'd be inclinded to give it a shot on their own.

Thanks,
Phil

Sure Phil, no problem. In fact, why don't you send me links to those forums so that I can answer any questions that people might have.

David

[Todd]

First off, I have a Jet DC 1200 with a cartridge filter from Wynn Environmental. They sell 2 kinds and they refer to them as the 35A series. One is spun bond, the other paper blend. The paper blend as alot more square footage of filter area and is cheaper, but probably does not last as long. Anyway, it always clogs up with shavings when I use my jointer or planer. I installed a flapper, but once it's clogged, it's clogged and if I forget to use the flapper, it can get so bad that I can't even move it. I also had installed a neutral vane.

David,

Not to get off target, but how did you creat a flapper on the wynn cartirdige filter?

Thanks, Todd

[windmill]

I've been thinking about building a flapper as well, but blowing it out with a compressor (low pressure - maybe 35PSI) seems to work well. Plus, the baffle really helps keep things clean. I've seen several designs - here is one and another

[D Romano]

First off, I have a Jet DC 1200 with a cartridge filter from Wynn Environmental. They sell 2 kinds and they refer to them as the 35A series. One is spun bond, the other paper blend. The paper blend as alot more square footage of filter area and is cheaper, but probably does not last as long. Anyway, it always clogs up with shavings when I use my jointer or planer. I installed a flapper, but once it's clogged, it's clogged and if I forget to use the flapper, it can get so bad that I can't even move it. I also had installed a neutral vane.

David,

Not to get off target, but how did you creat a flapper on the wynn cartirdige filter?

Thanks, Todd

Todd,
I constructed the flapper out of 3/4" baltic birch plywood and plastic from a Rubbermaid storage container. The plastic is a little less than a saw kerf thick. See the first photo below. Mount the plastic in a saw kerf along the sides of the plywood, shimming if needed. Put A 1/2" dado 5/8" deep down the middle of the plywood. This will allow a 3 foot long 1/2" threaded rod to be centerd in it. Centering aeverything is very important. Reinforce the assembly with steel cross pieces and a few bolts through the plywwod, rod and cross pieces to prevent the whole thing from falling apart when you turn the flapper. 

The flapper is mounted in the cartridge by first drilling a 3/4" hole in the center of the top of of the cartridge. Install the flapper/rod assembly into the cartridge. At the bottom, put a cross piece with a centered hole in it. Keep this piece as narrow as possible because it does block airflow. Put a washer and 2 nuts on either side of the cross piece. At the top, put a 3/4 OD x 1/2" ID oilite (spelling?) bearing over the rod and into the hole. For those unfamiliar, it is a oil impregnated bronze sleeve used as a bearing. This makes a nice interface between the rod and the hole in the canister. Then slide on a rubber washer to prevent air leakage, a washer, and 2 nuts. Tighten all the nuts using 2 wrenches. For a handle, I just used my box end wrench, put a washer on either side of it and fastened it down with a nut on top. Then cut the excess rod off. The wrench handle looks funny when you first see it, but it works great. See the second photo.

The third photo shows the construction of the flapper a little better from an angle

All of this is available at the hardware store. Make sure the plastic edge that wipes the filter pleats is parallel with them, only lightly touches the filter and has no sharp spots or you could wear a hole in it. Also get the straps to hold the canister down.

Having said all this, I hope that the baffle will preclude the need for a flapper. In fact, I hope to sometime soon by a 2nd filter from Wynn, and stack the 2 on each other. This would give me about 550 sq ft of filter, providing about 2:1 filter CFM to filter ratio that is recommend by manufacturers. (The other canister would have to have the top cut out to make it open on both ends)

david

[phil (admin)]

That flapper is the cats pajamas!  It looks absolutely foolproof!

You must have nice high ceilings if you can stack two of those filters.  Where do you keep your shop (basement, garage)?

[D Romano]

That flapper is the cats pajamas!  It looks absolutely foolproof!

You must have nice high ceilings if you can stack two of those filters.  Where do you keep your shop (basement, garage)?

The cartidges are 23" high. I currently only have 1 of them on the DC, but there is room for 2 of them under an 8' ceiling. The shop is a 1 car basement garage (it's a split level ranch). If 2 were stacked, then the handle for the flapper would have to be more like the ones you see on the Jet canister where they are bent down, hanging along side the cartridge. If I still need more space, I could take the casters off the DC which would lower it by about 2". I don't wheel it around anyway. Then again, I expect that with your baffle, their will be no need for a flapper. I would say that the only thing a flapper is good for is to dislodge the really big clogs. Maybe in a spun bond filter (mine is paper blend), the pleats are not packed as closely together and the flapper would work better, but then there is not enough square footage with those so you'd d really need 2 of them.

Here's a link that I found on Bill Pentz's site. http://billpentz.com/woodworking/cyclone/Links.cfm
http://www.farrapc.com/html_industryapps/WoodWork.pdf
It states that for systems that discharge wood dust the air back into the shop, not outside, that the ratio should be 2:1 but this is for a particular filter of theirs.

If you look at all of their different recommedations for the ratio though, you'll see that they are always 3:1 or better. http://www.farrapc.com/search_results.php?cx=007915651299152886568%3Ayoxgj5cmfcy&cof=FORID%3A11&q=ratio&sa=Search#1024

The Jet canister has a measly 84 sq feet.  Do the math. Even if the machine is actually pulling only 600 cfm, it is overloading the canister.
Check out the Wynn filters here: http://www.wynnenv.com/35A_series_cartridge_kit.htm

David

[Mike Goetzke]

David/Phil - I made a baffle like David's for my Jet DC1100 w/ canister. I had a piece of 14ga. sheet metal that's been around for years just waiting for this application. It took an hour at most to fabricate and fasten - thanks to the great directions shown here. Since I used thin metal stock I was able to form 3-tabs that I later bent and used to attach the baffle to the DC. I used pop-rivets in two locations and a bolt/nut in the third because the rivets I had on hand were not long enough. The three fasteners in the 120 deg larger diameter arc seem to be plenty. When I fired up the dust collector it does have a sort of low frequency resonance tone that wasn't there before, but, it's doesn't seem to be any louder and it's not an annoying tone. Of coarse time will tell if the performance has been improved.

Thanks for the post,

Mike

[Rick Potter]

Way to go David.  Your baffle in the DC is what I was speculating about in my post about going bigger.  When I get some time I will 'borrow' some of your hard work to make mine.  It will be on a 3HP four bag DC, and I will do it with no filters at all, just a lid over the top of the DC ring for the center outlet....
with a 6" from each side to a wye with one 8" outlet to the outside.  With the DC being as efficient as you demonstrate, I should not have much other than fine dust going out, which is where I want it.

Rick Potter

[D Romano]

David/Phil - I made a baffle like David's for my Jet DC1100 w/ canister. I had a piece of 16ga. sheet metal that's been around for years just waiting for this application. It took an hour at most to fabricate and fasten - thanks to the great directions shown here. Since I used thin metal stock I was able to form 3-tabs that I later bent and used to attach the baffle to the DC. I used pop-rivets in two locations and a bolt/nut in the third because the rivets I had on hand were not long enough. The three fasteners in the 120 deg larger diameter arc seem to be plenty. When I fired up the dust collector it does have a sort of low frequency resonance tone that wasn't there before, but, it's doesn't seem to be any louder and it's not an annoying tone. Of coarse time will tell if the performance has been improved.

Thanks for the post,

Mike

Hey Mike,
That sounds like a good design. I would say that a stiff sheet of steel is the best permanent solution. How'd you cut it?

It's possible that fastening it only along the 120 degree arc is causing the low frequency humming though. It's probably vibrating, acting like a big bass kick drum. The pop rivets sound a bit too permanent, what if you need to take the baffle out?

David

[Mike Goetzke]

Hey Mike,
That sounds like a good design. I would say that a stiff sheet of steel is the best permanent solution. How'd you cut it?

It's possible that fastening it only along the 120 degree arc is causing the low frequency humming though. It's probably vibrating, acting like a big bass kick drum. The pop rivets sound a bit too permanent, what if you need to take the baffle out?

David

David - I suspected the same thing about the resonance and indeed I can see the baffle moving on the unfixed side. Oh well - looks like it needs it's first mod. Those that are familiar with the ring that holds the bag in place on this DC know it's easy to apply if you insert the ring deep on the far side of the ring and then bring it down to the rim. Without a support in the 270 deg portion of the baffle I can still do this. If I add a support it may be a pain to c/o the bag - what' your experience David?

I used my Bosch jig saw to cut it. There are some small gaps where the baffle meets the DC that I need to fill but that should be no big deal.

Mike

[D Romano]

David - I suspected the same thing about the resonance and indeed I can see the baffle moving on the unfixed side. Oh well - looks like it needs it's first mod. Those that are familiar with the ring that holds the bag in place on this DC know it's easy to apply if you insert the ring deep on the far side of the ring and then bring it down to the rim. Without a support in the 270 deg portion of the baffle I can still do this. If I add a support it may be a pain to c/o the bag - what' your experience David?

I used my Bosch jig saw to cut it. There are some small gaps where the baffle meets the DC that I need to fill but that should be no big deal.

Mike

I actually find it easier with the baffle, because the ring fits nicely in a spot sized just right for it. Only other thing I'd mention here is that if you use a plastic bag inside the cloth bag, that you be sure to pull the slack out of it from the outside. Otherwise, the slack could be bunched up on the inside along the top and lessen the gap provided by the baffle. You want to keep that 1.25" open.

David

[Rick Potter]

One question.  Does the 1.25 inch gap apply to any size ring, or should it be bigger with a bigger size?   It seems like a 20" DC ring might take a larger gap than a 14 or 16".

Rick Potter