Some rocks in the collection drum?

E

Ed Haney

New member
I got my electrical done today so that my CV is now hot. Getting close!

I also bought a 30 gallon steel garbage can today to make a dust collection drum like the CV instructions recommend. Of course a 33 gallon poly draw-string garbage bag fits it perfectly inside the can with room to drape the edges over the outside of the drum (held there by the can top in operation).

I have seen people in the photo Gallery putting a steel wire frame inside their can to keep the poly bags in place while filling/operating. But why wouldn't some rocks or such in the bottom of the bag keep it in place while it is filling? I must be missing something. Putting some scrape wood or rocks to weight down the bag while it is filling and then throwing the weight away with the rest of the dust would keep from pulling something out of the full bag and making a mess, wouldn't it? Maybe I am missing something, so please set me straight with your experience.

Thanks,
Ed
 
Hey Ed,

I don't use a plastic bag at all but I don't see why you couldn't just use some rocks as you mention. The biggest thing would be the weight of hauling all the sawdust out with the added weight of the rocks. I'm sure once you get all your runs completed and fire it up you will be able to find out real quick if rocks or not is a good/bad idea. As long as they are not small stones I'm sure it'll work. The biggest thing is to prevent the bag from being sucked back up into the cyclone. I personally would just go with a chunk of mdf as weight.

Congrats on the cyclone, you're gonna love it!
 
Ed, You can create an air leak placing the bag over the top of the bin and then the bag would get sucked up into the cyclone. Putting a weight in the bag is not needed without any leaks and probably wouldn’t help with a leak. With no leaks, the bag would just fall to the bottom so you need something to hold the bag in place. That’s why the wire frame. I am using a Lawson Easy Bagger from Ace Hardware, a plastic sheet that holds it open, on a mini cyclone with some binder clips at the top to hold it in place and am going to add it to the cyclone.
 
Danscyclone said:
Ed, You can create an air leak placing the bag over the top of the bin and then the bag would get sucked up into the cyclone. Putting a weight in the bag is not needed without any leaks and probably wouldn’t help with a leak. With no leaks, the bag would just fall to the bottom so you need something to hold the bag in place. That’s why the wire frame. I am using a Lawson Easy Bagger from Ace Hardware, a plastic sheet that holds it open, on a mini cyclone with some binder clips at the top to hold it in place and am going to add it to the cyclone.
Click to expand...

Thanks, Dan.

That does clear it up for me. I had thought that using 1/2" foam weather stripping on the can lid would get me the air tight seal. The overlapping steel seam on the lip of the can is likely bigger than any folds from the poly bag draped over the side, so I thought I would be able to minimize the bag folds and get a seal with pressure on the can top against the steel seam, poly bag and then foam seal.

But if the experience of the group is that this will not seal, then I am likely going to fail here and need to follow your example. But this makes me wonder how the steel can seam will seal. I guess I could add a small amount of caulking at the seam to help smooth it out some.

Dan, are you using a 30 gallon steel can with the Lawsaon Easy Bagger? Did you have to modify it?

Ed
 
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Ed, I don’t have any experience with having the bag over the top but that’s what I have read here. I am using the Behrens 30g can that I had to cut off a 5in. section around the bottom so it would fit under the cyclone and crimped it enough to fit back together. The Behrens are thicker meatal than the cheaper ones. I found some duct sealant at Lowes in their havc section that works real well and sealed all the seams and at the handles. The foam seal at the lid will work. I haven’t put the easy bagger in it yet but will be soon. I’ve been experimenting with a mini cyclone that I am using one in, had to cut the easy bagger down for the height and it’s working real well. The easy bagger is just a vinyl sheet that you roll up and put it in the bag to keep it expanded.
 
Dan,

I have the same 30 gal Behrens can from Lowes. I sealed all the handles and seams, inside and outside with the same DAP Alex Plus caulking as I used to seal the seams on the CV (same caulk brand as recommended in the CV instructions). I don't have a jigsaw so I need to buy some snips to cut the hole in the top.

I certainly don't want to suck a bag through the impeller, but it would be nice to be able to seal it while draped over the top to make emptying it less messy.

Ed
 
Having the bag get sucked up into the impeller wouldn’t be a pretty sight. To make it easier to clean up, I mounted a 6 in. plexiglas tube in the lid that extends into the can 3in. so when my photo cell sensor goes off the dust is a couple inches below the top and I can get the lid off and the can out without spilling any.
 
Our experience is that the bag does get sucked up into the cyclone, even without leaks - honest!! Even Bill Pentz talks on his site about having to hold the bag down with magnetic clips to stop it being sucked up until there is weight in it. There is negative suction in the cyclone that does extend down into the bin to a certain degree. You notice it more if you have a short connection between the cyclone and the dust bin. If you have a long connection or a large dust bin you don't see the effect to the same degree.
Once there is some weight in it (some amount of chips or dust), the bag going up is not a problem any more. Using wood or rocks to weight it initially does work well. We've done it. The only disadvantage to doing this is dependant on what you are planning on doing with your dust. If you plan to spread it anywhere, you then have to deal with chunks of wood or rocks in it. If it just goes to the garbage bin, it isn't a problem.
 
Waste bag support

Waste bag support

Ed,
The turbulence in the can could be quite intense so an even bag support would be better than a few weights in the bottom.
My thought lean towards making a cylinder out of slippery plastic - one of those plastic sliders that were on the market for kids a number of years ago.
I found this on the web
http://www.buzzillions.com/reviews/lawson-products-plastic-bag-holder-40500-reviews
Seemed for awhile they were at every trade show.
It would save need a supply of rocks in the shop ;)

Don
 
The bag would get sucked into the cyclone without any leaks...the area inside the bag would be at negative pressure but the area outside the bag (but still in the bin) would still be at atmospheric pressure.

If you neutralize the pressure difference AND have no leaks, the bag shouldn't move (or at least not get sucked into the cyclone body). I'm going to run 1/2" conduit from the lid to the body of the bin to equalize the pressure...we'll see if that works. This way you wouldn't have anything extra in the bags.

I'm still a little ways from turning the whole system on, but I'll post once I know if it works. I guess an easy way to test it would be to put a small tear an empty bag, as long as the tear is INSIDE the bin...maybe I'll do that and make sure it works before I go to the trouble of running the conduit.
 
Aegwyn11 said:
The bag would get sucked into the cyclone without any leaks...the area inside the bag would be at negative pressure but the area outside the bag (but still in the bin) would still be at atmospheric pressure.

If you neutralize the pressure difference AND have no leaks, the bag shouldn't move (or at least not get sucked into the cyclone body). I'm going to run 1/2" conduit from the lid to the body of the bin to equalize the pressure...we'll see if that works. This way you wouldn't have anything extra in the bags.

I'm still a little ways from turning the whole system on, but I'll post once I know if it works. I guess an easy way to test it would be to put a small tear an empty bag, as long as the tear is INSIDE the bin...maybe I'll do that and make sure it works before I go to the trouble of running the conduit.
Click to expand...

That idea crossed my mind but I figured you would have to have some sort of grid to create a void so all of the air could be sucked out, or a number of vacuum points around the bin.
What about not bringing the bag to the top of the bin? That should allow the air on both sides to equalize, but the bag would have to be secure....

Don
 
Don01 said:
That idea crossed my mind but I figured you would have to have some sort of grid to create a void so all of the air could be sucked out, or a number of vacuum points around the bin.
What about not bringing the bag to the top of the bin? That should allow the air on both sides to equalize, but the bag would have to be secure....

Don
Click to expand...

I don't think you'd need to worry about the air being sucked out...as long as the pressure inside the bin and inside the bag is the same, you should be fine. There should be no upwards air movement out of the bin (assuming you're all sealed up).
 
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