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| How much CFM? http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=1683 |
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| Author: | John Elshaw [ Thu Apr 14, 2005 3:53 pm ] |
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What is the minimum CFM required to adequately pull dust from a Woodtek 25" dual drum sander? I figure if the dust collector can handle a drum sander, it should be just fine with all my other tools. Thanks! John |
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| Author: | Mario [ Thu Apr 14, 2005 4:05 pm ] |
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Get as much as you can afford to buy, and afford to tun(power wise). Honest, you can't have too much. I got my collector at an auction, and from what I can gather, it pulls between 2-3000 cfm. I can thickness sand all day without a hint of dust in the air. The main reason to get lots and lots si that yuo want to let the bags "cake over" with fine dust; new bags will seem to make dust <g> When you thickness sand, new bags will simply blow that really fine dust back out, making things worse. But once you have a few hours on it, it will begin to build a layer of fine dust inside the bags, and this dust cake will act as a secondary filter. Think of it like putting a thick felt layer inside the bags. That cake kills the CFM, and that is why you want to start with plenty. I likely killed half my CFM with my caked over bags, but it still pulls plenty, and no fine dust gets out at all. Which reminds me, the dang things are full... |
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| Author: | crazymanmichael [ Thu Apr 14, 2005 4:08 pm ] |
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this site has a lot of info on the necessary flow required to mosve fine dust. http://billpentz.com//woodworking/cyclone/index.cfm |
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| Author: | bob J [ Thu Apr 14, 2005 10:08 pm ] |
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What id good cfm. Is the Delta collector any good? Do you aalso use air cleaner. What brand and what power? Thanks |
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| Author: | crazymanmichael [ Fri Apr 15, 2005 12:57 am ] |
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bob yes i use air cleaners. have a large dust collector; 6" pvc mains and drops to 4" connections and ports. but it seems that some always escapes. mine are home built. i found four delta bag filters at lowes on sale for $5 (list about $25-30) each a few years ago and needless to say snapped them up all of them. squirrel cage fans from furnaces provide cheap, even free, air flow. prefilters are off the shelf furnace units. do a good job of keeping the fug down. i also have a small mobile collector that i use for ad hoc job situations. standard bags are almost useless; let the fine stuff through and that is what does the damage to the lungs. get the micron or sub-micron bags/filters. i am thinking of converting over to the filters. take up much less space, easy to clean, and provide fine filtration from the start without the flow restriction that mario refers to above. |
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| Author: | stan thomison [ Fri Apr 15, 2005 1:06 am ] |
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John I have one on a dual drum grizzly that is 2hp 1700cfm I got on ebay. works well, and have other port on my griz downdraft mat (less than $50 on ebay)works pretty well. would like more? always. if do that, and when assembly and i know you would know this,make sure gates are closed. i haven't on occasion and then wonder why the downdraft table isn't pulling like i want |
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| Author: | EricKeller [ Fri Apr 15, 2005 1:46 am ] |
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Another thing to consider is replacing your filter bag with a filter. Bill Pentz recommends Wynn I just bought a used Onieda. I'm planning on buying the Torit filters for the output. |
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| Author: | Mario [ Fri Apr 15, 2005 1:56 am ] |
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and provide fine filtration from the start without the flow restriction Any time you go to finer filtration, you get more restrcition. No ands, ifs, or buts about it. The finer the holes in the filter media(which is what lets the filter move air, after all). That's why a pleated filter is pleated; more surface area to make up for the smaller holes. At any rate, the bottom line is to get the most flow, with the finest filtration; most collectors are made to such chips and shavings, not fine dust. Keep that in mind.... |
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| Author: | crazymanmichael [ Fri Apr 15, 2005 4:34 am ] |
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semantics. agreed the larger surface area compensates for the increased resriction of the smaller holes. but the issue is restriction of flow through the system. the result of using filters is that for a given size filter medium using a pleated filter results in less net restriction to the flow of air through the system, with the added plus that it is easier to maintain that higher flow because of the ease of cleaning, without going through the fine dust passage phase while bags build up the internal dust coating. pleated filters are a better option than bags, albeit at a slightly higher cost. |
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| Author: | John Elshaw [ Fri Apr 15, 2005 9:13 am ] |
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I was looking at an Oneida that is rated around 1400 CFM. However, the inlet/outlet opening is 7". I assume if I change the inlet size to 6" to match the ducting and hoods, that this will restrict airflow, and hence the actual CFM will be reduced. This makes it hard to compare apples to apples. So I guess my question is does anybody know how much of a reduction in CFM is achieved by reducing the inlet size to 6" vs 7"? Cheers! John |
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| Author: | crazymanmichael [ Fri Apr 15, 2005 7:33 pm ] |
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i think the above referenced site give info on such matters. in addition he gives info on the effects of rt angle bends vs 45 + 45, different types of hose, etc. best to read what he has to say before making any decisions. |
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| Author: | D.L.Huskey [ Mon Apr 18, 2005 3:38 pm ] |
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Has anyone here built or seen the Cyclone in action, mentioned in the above link. I have a 1250 CFM collector and would like to add a cyclone in front of it. I was just wondering how well this one works. |
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| Author: | EricKeller [ Mon Apr 18, 2005 4:43 pm ] |
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I suspect it works very well. He's gone through several iterations on the design. It was too much work for me, but it looks like just about the best bet. I'm planning on souping up the Oneida according to his recommendations. |
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