Will a baffle help here?

[mrlysle]

Hello all. I'm new here, and would like your help, and expertise. I wanted a better dust solution for my modest shop. I don't have a DC, and really can't afford one atm. I have a Craftsman shop vac, and attached a picture of it, so you can see the exact model. I also just recently discovered the " Thien baffle", but before I knew anything about it, I was browsing around on YouTube, and found a dust collector build that looked like would work for me. Here's a link, for those that would want to see it. www.youtube.com/watch?v=lNDc66V1_64
So I ordered my fiber drum, got the rest at the local hardware store, and built it. I made a couple mistakes as I went, corrected them, and finally got it finished. I've made some adjustments since, and attached pictures of the current configuration. Why I need your help, is that the shop vac is "scavenging" dust/planer shavings/debris from the bottom of the barrel. The reason I'm saying this is because I can empty the shop vac container, turn it on with the hose from the collector/separator just laying on the floor, (not actually sucking anything up) and after running for a few minutes, there is a small amount of debris in the shop vac, and on the filter. It's not a lot, but more than I think it could be. Obviously, the longer I let it run, the more stuff ends up in the shop vac. Again, this is with the inlet hose to the collector just lying out in the open. The unit does seem to work for the most part, and in one photo, you can see the "vortex" pattern in the debris at the bottom of the fiber drum. So, would one of Phil's baffles be what I need here? Or some other baffle? If so, where would be the best place to put it? I was thinking of snugging it right up to the bottom of the wooden caul, that holds the horizontal pipe. If anyone is wondering, I did initially play with placement of the bottom of the vertical pipe, the one that goes to the shop vac. The original design called for the bottom of the vertical pipe to be 3 inches below the horizontal pipe. But the "scavenging" was worse when it was located there. I finally ended up with it where you see it in the picture now, just even with the bottom surface of the lid. I used 2 inch PVC pipe. The drum is approximately 18.5 inches in diameter, and 26 inches high. Again, I didn't build this unit ignoring the Thien baffle, I just didn't know about them at the time. What do y'all think? Any help/suggestions would be greatly appreciated!

[retired2]

Given the way your inlet pipe enters the drum, I'm not sure what would happen if you added a baffle.  Ideally, with a side inlet, the pipe should enter tangentially and be cut off flush with the inside diameter.  What you have is going to create an awful lot of turbulence in the separation chamber - the chamber being the volume above the baffle you are proposing to add.  Also, with a baffle, your outlet pipe should extend into the chamber so that it is at least to the centerline of your inlet pipe or below.

Now that I think about it, you can't add a baffle with the inlet pipe the way it is.  The baffle would need to be attached to the lid so that you can remove it to empty the drum.  There is no way you could add a properly designed baffle without re-doing the inlet pipe.

You might be better off with the separator inlet and outlet on the drum lid.  Maybe that was your intent and I just missed it.

[mrlysle]

Thank you retired2, for your quick reply! I don't mind reworking my build, to make it work better. I can remove the side inlet pipe, and cover the hole with some more sheet metal. As it is, the pipe to my shop vac, is dead center in the lid. So I can redo the piece of lumber on top, and add the second pipe beside it, like Phil shows in his photos. I'll also need to put a 90 degree elbow on the bottom of the pipe as well, correct? Then I would build the baffle, and attach with stand offs, to the bottom of the lid? Thanks again for your time and expertise. 

[retired2]

Thank you retired2, for your quick reply! I don't mind reworking my build, to make it work better. I can remove the side inlet pipe, and cover the hole with some more sheet metal. As it is, the pipe to my shop vac, is dead center in the lid. So I can redo the piece of lumber on top, and add the second pipe beside it, like Phil shows in his photos. I'll also need to put a 90 degree elbow on the bottom of the pipe as well, correct? Then I would build the baffle, and attach with stand offs, to the bottom of the lid? Thanks again for your time and expertise.

You are on the right track, but I'm not an expert on the lid-type separator's.  Maybe someone else can jump in with some advice.  The only caution I can give you is make sure you keep the inlet elbow above the baffle about 3/4" to 1".  If you don't, you might get a bird's nest accumulating behind it.

[bbain]

I would add some external support to the side entry pipe, then cut it flush inside, and add the baffle attached to the lid.  That way you will have less work, and have less of performance hit because of the 90deg bend with the through the lid configuration.

Just as a side note, the dust being sucked up from the drum to the vac when not actively collecting dust is a perfect example of the "scrubbing" that the Thien baffle prevents.

[retired2]

I would add some external support to the side entry pipe, then cut it flush inside, and add the baffle attached to the lid.  That way you will have less work, and have less of performance hit because of the 90deg bend with the through the lid configuration.

Just as a side note, the dust being sucked up from the drum to the vac when not actively collecting dust is a perfect example of the "scrubbing" that the Thien baffle prevents.

I think if he just trims off the inlet pipe flush with the inside of the drum, he will still have two problems.  Since the inlet pipe is not tangential (appears to be inboard by about 2"), it will create more turbulence that one that is truly tangential.  That will likely compromise air flow and separation.  Secondly, the aim of the inlet pipe, since it is not tangential, is slightly closer to the outlet pipe.  That may result in some waste by-pass. 

Now I hasten to add that in spite of these issues, it will still work - just not quite as good as it could.  That is the beauty of the Thien baffle.  It is pretty forgiving.  You can get a large part of the total performance with some pretty basic implementations.  After that it quickly becomes a case of diminishing returns.

[tvman44]

I am no expert but do have 2 lid type separators and would recommend going that way and plugging up the hole in the side.

[mrlysle]

Thanks everyone for your replies. I think I'll put both pipes through the lid, and hang a baffle under it. I need to get a couple things. I'll put hose adapters (or dust ports) on the lid on the outside. Can they be straight, or should they be at some angle? The pictures of the lid Phil put on his home page show his to be at an angle. Looks like exactly what I just mounted on my bandsaws lower wheel cover. I'll order a couple more and use them. Sound good? Thank you all for your help. 

[mrlysle]

Ok folks. I removed the pipe coming through the side of my drum, and built a baffle. Ultimately, I hope it will look and work like Phil's original. I'll post some pics when I get a chance. My latest question pertains to the pipe that goes to my shop vac. It's located dead center in the lid. It is still exactly like the above pictures show it to be. But now that I've mounted the other pipe, (inlet pipe from the tool being used), and will mount an under lid baffle, should the pipe in the middle now protrude down into the cavity above the baffle more? How much? I read somewhere else on the forum here, that it was recommended to have the bottom of the pipe approximately at the centerline of the 90 degree elbow? The bottom edge of my elbow will sit around an inch above the surface of the baffle, so the above recommendation would put the bottom of the pipe in the middle of the lid about 2.5" or so above the surface of the baffle. Sound good? Thanks again everyone for their help!

[mrlysle]

Ok all. My final update, and hopefully this will help anyone else that starts a dust collector/separator on a different design, like I did. I do want to stress that I wasn't aware of the Thien baffle when I started my build. I was fortunate to later find, and watch some of videos on YouTube that showed this "new to me" baffle system. Then I found this site, and benefitted greatly from it. My initial build was exactly like the pictures show thatI posted above. I was getting bad "scrubbing", or I believe at one point I called it "scavenging". In other words, my shop vac was ultimately pulling the dust and debris that found its way to the bottom of my fiber drum, back into the shop vac. So I asked for help here, and now I have a system that works actually better than I hoped! Retired2 got me started in the right direction. The center outlet pipe, the pipe that goes to my shop vac, is still dead center of the drum lid. No changes there, except for the depth of the pipe into the drum, which I lowered, after finishing my baffle. I removed the inlet pipe from the sidewall of the drum, and moved it to the lid, right to the edge. I used another piece of sheet metal to plug the holes left from the pipe, and screw holes for the original wooden caul the pipe was mounted to. The sheet metal serves a secondary purpose of preventing the wear that would occur from the sandpaper effect of the dust/planer shavings/wood chips entering a high speed, and rubbing the wall of the fiber drum on the way to the bottom. I built my baffle from the only thing I had that was appropriate. 1/2" MDF. I would have used 1/4" tempered hardboard if I had it, and someday I will build another baffle out of it, and replace my current baffle. I used 1/4" all thread rod, covered with steel tubing to act as spacers to mount the baffle to the lid. The rest of the details I just tried to match the look of Phil's unit he shows on his page. My baffle is sitting 1" below the inlet elbow, and the outlet pipe extends to approximately halfway to the centerline of that elbow. It works very well as it sits. I've used it a lot since finishing it, and there isn't ONE small wood chip or planer shaving in the bottom of my shop vac now! And nothing on the filter either! I'm sure I'm getting some of the super fine, talcum powder like dust that refuses to settle to the bottom of the drum, but nothing that will cause me problems between drum emptyings. I'm very happy the way it turned out, and hope anyone else who wonders if they can "get by" without the baffle will look at the before and after pics, and understand the terrific difference I've experienced from the baffle. Thanks to all for your suggestions and help for a newbie!  :D 

[retired2]

Ok all. My final update, and hopefully this will help anyone else that starts a dust collector/separator on a different design, like I did. I do want to stress that I wasn't aware of the Thien baffle when I started my build. I was fortunate to later find, and watch some of videos on YouTube that showed this "new to me" baffle system. Then I found this site, and benefitted greatly from it. My initial build was exactly like the pictures show thatI posted above. I was getting bad "scrubbing", or I believe at one point I called it "scavenging". In other words, my shop vac was ultimately pulling the dust and debris that found its way to the bottom of my fiber drum, back into the shop vac. So I asked for help here, and now I have a system that works actually better than I hoped! Retired2 got me started in the right direction. The center outlet pipe, the pipe that goes to my shop vac, is still dead center of the drum lid. No changes there, except for the depth of the pipe into the drum, which I lowered, after finishing my baffle. I removed the inlet pipe from the sidewall of the drum, and moved it to the lid, right to the edge. I used another piece of sheet metal to plug the holes left from the pipe, and screw holes for the original wooden caul the pipe was mounted to. The sheet metal serves a secondary purpose of preventing the wear that would occur from the sandpaper effect of the dust/planer shavings/wood chips entering a high speed, and rubbing the wall of the fiber drum on the way to the bottom. I built my baffle from the only thing I had that was appropriate. 1/2" MDF. I would have used 1/4" tempered hardboard if I had it, and someday I will build another baffle out of it, and replace my current baffle. I used 1/4" all thread rod, covered with steel tubing to act as spacers to mount the baffle to the lid. The rest of the details I just tried to match the look of Phil's unit he shows on his page. My baffle is sitting 1" below the inlet elbow, and the outlet pipe extends to approximately halfway to the centerline of that elbow. It works very well as it sits. I've used it a lot since finishing it, and there isn't ONE small wood chip or planer shaving in the bottom of my shop vac now! And nothing on the filter either! I'm sure I'm getting some of the super fine, talcum powder like dust that refuses to settle to the bottom of the drum, but nothing that will cause me problems between drum emptyings. I'm very happy the way it turned out, and hope anyone else who wonders if they can "get by" without the baffle will look at the before and after pics, and understand the terrific difference I've experienced from the baffle. Thanks to all for your suggestions and help for a newbie!  :D

Congratulations!  One last word of advice - if you decide to build another fancier separator, don't do it thinking it will collect all of the talcum powder.  It will probably miss the same amount as your current separator.

[mrlysle]

Thanks retired2! That's good to know, and it makes sense. I can't imagine the "talcum powder" having enough weight and/or mass to sink to the bottom like the other stuff. I really appreciate your time in responding and helping me. Stay safe my friend!  ;)