J. Phil Thien's Projects

Mike,
My ring fits very tightly. Before the baffle was there I used to do what you say, but since then I've learned that the ring is very flexible and can take a surprisingly sharp bend. Youu know, I thought about it later on, and it occurred to me that I put a 1/4" gap between the baffle and the snap in ring. I used pieces of hardboard as spacers. I failed to mention that in my original long post.

My impression is that the flour trick was only for bags. The canister is already a superior filter, I don't think it needed the flour. Your test results are encouraging, but I think the top of the baffle is going to be scrubbed clean no matter what. Wipe the pleats of the cartridge with your finger to see if there is any flour there.

David

Quote from: Mike Goetzke on January 27, 2008, 10:48:55 AM

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

Quote from: Mike Goetzke on January 26, 2008, 10:50:02 PM
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

Quote from: phil (admin) on January 25, 2008, 06:54:28 AM
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

Quote from: Todd on January 24, 2008, 08:37:32 PM

Quote from: D Romano on January 24, 2008, 07:45:40 AM
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

Quote from: phil (admin) on January 24, 2008, 05:12:05 PM
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

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

Stumbled across this earlier

"Top Hat separator"

http://www.cat-vacuum-collectors.com/vacuum-hose-and-tools/hoppers.htm

Note the configuration, and the price !!!

Quote from: phil (admin) on January 16, 2008, 07:04:06 AM

Quote from: D Romano on January 15, 2008, 08:38:50 AM
The separation could be alot better for the fine dust.

BTW, if you perform that test with a large cyclone, you're still going to fill your shop with fine dust.

In fact, there was a guy that posted in one of the WW forums in the last few weeks saying that his shop was filling with dust and he tracked it down to a small 1/8" hole in a weld on his cyclone (I think it was an Oneida).  The hole was in the plenum that feeds the filter stack.  So this was separated air, as clean as the cyclone could get it.  And a 1/8" hole was filling his shop with dust.  Dust that would have normally been caught in the filters.

I guess what I'm saying is, don't believe everything you read about the separation rate of large cyclones.  They still shoot plenty of fines to their filter stacks.

That is a very good point, but in my test, I think that most of the fine dust was being picked up from the collection bag and blown back out. I only threw in a small handfull of shavings. It seemed that the longer I let the DC run, the more dust was in the air. It was as if I'd done alot of sanding with a ROS. If my observation is correct, then it suggests that leaving a DC on for longer than necessary just clogs the filter with fine dust. An interesting test would be to put some blue chalk in the collection bag, turn the DC on and see if the canister filter gets colored.

David

Sorry for the delay, I still want to send some pics of my setup. In the mean time though, I have putting some wood through my jointer and at first glance, the separator seems to be working. The flapper I installed in the canister was very easy to turn telling me that there are not alot of big chips clogging the pleats.

Also, I took the canister off and turned the DC on to see first hand what happens when the air swirls around. It was interesting. The air emerges from the DC separator ring in a swirl pattern, with only 2 distinct air streams shooting out of the hole, about 180 degress from each other. The location of one of them correlates with the location of the air stream entering the separator ring. (think neutral vane configuration) The air swirls around, hits this air that's entering and gets deflected up through the donut hole. The air does not come straight up. I am trying here to attach a drawing:



I then took a handfull of large chips, the puffy kind the you get from planing or face jointing pine and through it into a dust port. I wanted to see what would happen when it entered the baffle area. It happens very fast, but I could see the shavings slip down into the gap around the outside edge of the baffle. They did not come back out. Some finer dust did, and after running the DC for a few minutes, the shop had a lot of dust in the air. The separation could be alot better for the fine dust.

Since the dust does not naturally want to come up straight through the big donut hole, I think I will install an outlet pipe in it, making it more like phil's original garbage can separator. Making this outlet pipe smaller in diamter and/or lonnger will help the separation but increase static pressure.

Phil,
It sounds like your shop is alot cleaner than I was thinking, but is the whole whole filter doing the brunt of the work? I thought the only ambient air cleaner was the small Shop Fox one. Is the Honeywell getting clogged up when you use the shop? If you don't mind me asking, how clean is your tissue?

You are correct about BP's findings. He seems to be saying that it is impossible, in a hobbyist environment, to control the dust to the degree he claims is necessary.

David

phil,
I'm not sure how small your shop is, maybe 100 square feet? The size of the shop has a lot to do with the concentration of particles (duh) and with so little airflow to your machines, I would not be suprised if your shop is hazardous to your health. I'm not as militant about all this as Bill Pentz, (and you don't even need to ask him what he thinks about this, you could already guess) but I have become at least alot more concious of what I am breathing. A couple years after buying our fixer-upper house, I started getting migraine headaches. I never wore a mask except for when it was obvious to (can't see across the room because of the drywall dust) or if painting in a small closed room (different type of mask). I don't know if this caused my headaches, but I can imagine it was pretty unhealthy. Here's my setup:

I have a 1 car garage in the basement which is 12x23 with an 8 foot ceiling. I have an 8" jointer, planer, a contractor style tablesaw with a 50" fence and a Bench Dog cast iron router table attached to the side, a drill press, a miter saw and a small belt/disc sander. For the hand helds, I have routers, palm sanders, circ saw, jigsaw, etc.

For dust collection I have a Jet DC 1200. The bottom bag is plasctic and the filter is a 274 sq ft paper blend canister from Wynn environmental. I plan on adding a second one to it. It's a good deal for 90 bucks. Inside I made a flapper to dislodge dust build-up. (hopefully this will be a lot less with your baffle design) I run 6" ducts wherever I can. Currently, I have a the 12" mitersaw mounted over a down draft hood and my jointer hooked up to it. I can run a 4" flex hose to my planer when I use it and will soon enclose the underside of my router table and hook up the 4" flex hose to that.

For other tasks, such as the top of the router table, I have a shop-vac and a Oneida Dust Deputy. I works great. A shop vac is nearly useless in a wood shop with some sort of preseparator. I also use this for my palm sander and when I have the patience, for the hald held router.

Finally, for ambient dust, I have a Jet air cleaner hanging from the ceiling, the 1000 cfm model. I operate it on HIGH and I try to wear a good quality N95 dust mask, the kind with a little respirator and nose crimp. I think it it is a 3M #8511. I wear this because I can't tolerate the air cleaner being on the whole time, it makes too much noise, so when I turn it off, I'm still safe.

Bill Pentz would probably frown at this, but I use a my nose and a tissue to tell me how clean my air is. After all day in the shop, I'm still clean if I've got either the air cleaner or the dust mask on. Hey, when I work outside raking leaves or digging, or mowing the lawn I'm breathing in a lot more crap that this.

I found some info on that particle counter, http://www.hvac-talk.com/vbb/archive/index.php?t-150973.html and it seems like a good product. Can't believe it goes for only $149. Your Shop Fox air cleaner is too small for your shop, get a dust mask.  Also try to use less MDF, that stuff is really just pressed powder and glue to begin with.

-David

I looked a bit closer at your photos of the elbow locations, and I think that the reason why the performance was worse with it closest to the edge of the can is that the elbow is actually pointed toward the can. As phil has stated, turbulence is your enemy here. You need to keep the incoming dust stream tangent to the side of the can because you want it to slip through the gap in the baffle. As the dust is bounced ofr blown towards the center, it becomes more likely to get sucked up through the outlet pipe.

The ideal would be to mount inlet on the side of the can like a DC or cyclone would do, not the lid, but this is more difficult for sure. Not impossible though and it would make the lid easier to remove with only one hose stuck in it. What you are calling positions are really angles. To find the optimum position, you would need to offset the hole in the lid that the elbow fits through, while keeping the dust stream tangent to the edge of the can. What you will find in doing this is that closer the hose gets to the center of the can, the more turbulence will be created because the angle of attack on the side of the can will get steeper, i.e., in the center , the dust stream would be hitting the can head on no matter what angle it was placed at. (This function follows a sinusoid) The least turbulence will occur when the mouth of the elbow hugs the edge of the can.

David

Placing it under the blower on the 760 is a good idea. If there is enough room under there, it is really an ideal configuration. Why doesn't it work well enough? Does the DC have a 5" inlet to the blower? If so, why not use a 5" outlet from the pre-sep?

Quote from: phil (admin) on January 07, 2008, 11:04:31 AM

Quote from: D Romano on January 07, 2008, 09:22:49 AM
Had another thought- In a DC, the separator ring is a doughnut with about an 8" hole in the center. Anyone have any thoughts on making that smaller? I'd guess that smaller gives better separation but at the cost of reduced airflow.

Yep.  You may be able to choke it down a little w/o impacting the overall CFM (especially if you're using 4" ducting).  But I'd try leaving it as-is for now.  8" should still leave a 5" or so ledge at the edges, which should be plenty.

I use 6" ducting, but after the impeller, there is a 4" duct leading to the separator ring. That step down in size must really increase the velocity. Seems like it would be better to increase the diameter after the impeller, not decrease it.