I'm just starting to set-up a workshop at the "new" house. The floor is now concreted and painted so thoughts are starting to turn (in parallel with the zillions of other projects that I keep discussing) to dust extraction. The tools generating wood dust are: a Kity Bestcombi 2000 (saw, thicknesser, planer, spindle, etc), a Shopsmith 510 (lathe, saw, horizontal boring, etc), a bandsaw and the usual list of routers, jigsaws, jointers, etc. For collection there's a small Kity dust extractor. It's about 4m x 4.5m and will be for both metalwork and woodwork. I plan to build a small dedicated area for the dust extractor and to use an old kitchen extractor to draw air from that area to the outside world.
Some of the thoughts going around my head are: is a cyclone worthwhile? should I use plastic or metal ducting? will the Kity extractor have enough suck to extract effectively if I put the ducting at ceiling level? Any comments on the above? What have other people done for dust extraction?
Its a big subject... and you have conflicting requirements to deal with...
So for example a planer/thicknesser will generate large volumes of coarse wood chips/shavings, and only a small mount of fine particulate dust. A router or sander the reverse.
Large machines favour massive volume of air moved at speed - and the amount of "suction" is less important. Small hand held tools using small hoses, work better with higher suction levels, but the quantity of air movement is less important. (for complete collection, the air speed ideally needs to exceed the maximum chip speed, coming off the periphery of the blade etc)
The large coarse shaving make lots of mess and nuisance, but represent less health hazard. The really fine stuff is potentially dangerous - and the effects are cumulative. So the more woodwork you do the more important dealing with it becomes.
So you will likely need several collection strategies, unless you can go nuclear with a big cyclone that can manage lots of air speed, volume, and pressure, and so can collect pretty much everything, from any tool. (even then hand tools would pose a problem).
My personal setup (and this its not ideal - treat this just FYI), is a partly ducted 1.5hp chip collector (dual bag type) for planer / thicknesser/ table saw, band saw. Also sometimes with a big air funnel on a stand type attachment to try and catch the mess spewed from some routing applications. This has 2.5m of flexible 4" hose on for connection directly to some things. at other times it connects to an overhead 5m length of 110mm soil pipe to get to the other side of the shop, thence another length of flexi hose for dropping down to the thicknesser, planer, and bandsaw without being so much of a trip hazard. It works, but TBH, and HP of power would be good - especially on the longer duct run.
I use a wet'n'dry shop vac with fine filter bags for small tools and fine dust collection.
I run a ceiling mounted dual stage JET air cleaner for mopping up anything that gets airborne.
Lastly a decent 3M half face mask respirator when doing anything particularly risky like processing MDF, or a long session at the table saw (mine does not have over the blade collection - so some always gets ejected up and at you)
I would recommend a read of Bill Pentz's site on the subject:
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(its a tad more commercial now that he actually manufactures the Clear Vue kit, but much of the original research and detail is still there)
Do those dual bag types do good filtering of fine dust? If I had one I would not want it in the shop but outside so that dust couldn't be released in the shop. A little project to build a small side extension?
My Vac (Bosch GAS25) certainly does a better job of containing dust than any bag type dust extractor I have seen. You can certainly sand plaster and stuff with no visible dust using a random orbital sander.
The dangerous stuff is pretty close to invisible to the naked eye and goes straight through most "dust" masks that they sell in B&Q.
My brother is a dedicated turner and woodworker, and that is exactly what he did [1]. A sort of lean to extension, probably 4 ft wide, 2 deep and 4 high. Sadly, I have no idea what the extraction kit inside actually is. All I really notice is large bore pipes and stuff. I think it is designed to extract dust rather than larger shavings, the logic being that the dust is more unpleasant and less healthy. I'll ask him next time we speak.
[1] He builds sheds like most of us change socks. His workshop is huge, then there is the extension, a smaller metalwork shop, a shed where he stores the wood scrounged after October '87, a general storage shed, garden shed etc.
Just to say by way of minor contribution, I use one of those attached to power tools in the limited space/ventilation of my cellar. It really does save a lot of tidying up, and has the bonus of a mounted power outlet triggered by the mains power tool.
Quite how much it contributes to safety, I'm not sure - so do tend to wear a mask as well, especially if doing a number of cuts or working with something nasty like MDF.
I got it from Lidl - amazing suction, but noisy and expensive bags. I bought some generic bags off ebay, but they tend to rip.
I do know that static in plastic ducting for lightweight dust can be an issue as it sticks to the sides. Also I do hope you have good fire prevention, nothing like sawdust for a nice flash fire, except probably four. Brian
I have recently discovered that the replacement filter bags for my
*Henry* split at the seam when used for plaster dust!
The workshop has a twin bag dust extractor. Which is fine for most of my planing/sawing/routing jobs but I can confirm something said by Phil? Corrugated piping is very hard on air flow.
Following on from your other thread when you mentioned low bandwidth. I have put this video of my extraction set up in a drop box so you can download the file however long that takes and then watch it locally rather than have stop start view in real time.
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The cyclone itself was built from an Ikea large galvanised flower pot and several woodworkers built them but Ikea have stopped selling them now. They are not too bad to fabricate from sheet metal if you can access the material. There are other separator designs out there that are easier to make eg Thein.
Having the blower in the roof and the rest of the extractor parts stacked vertically against the wall minimises floor space lost and makes emptying the bin fairly easy. try and avoid using a 200 ish litre drum even though they are easy to get, they are 'kin heavy full of sawdust. I think my bin is about 60 litres but 30 mins work on the planer can fill it!
Hope this helps. Incidentally I think you are pissing into the wind try to do anything useful with a kitchen extractor fan. My blower is 14" with 3hp motor. Now that really sucks!
In their basic form (cloth bags top and bottom) generally no - they are usually intended to operate as chip collectors rather than dust extractors. Feeding them fine dust will often just make sure it gets wider air circulation.
Having said that you can change the top filter bag to one that does collect finer stuff, or fit a pleated cartridge filter to the top. In both cases you need to use a sealed plastic bag on the bottom. Doing that will often lose too much airflow on the smaller machines though.
Yup, or if there is space an internal partitioned off space...
That's where the 3M respirators designed for particle and vapour control are worth having. They also fit the face much better and don't steam up your glasses.
The main issue with sawdust is when something hot enough to ignite it is ingested into the collection system (like grinding sparks etc). There is a myth that ignition can be caused by static build up, but I have never seen any evidence to support this.
Agreed! My system must have about 25m of 110mm soil pipe and running for about 9 years now and the only effect of static is that the outside of the pipe attracts the fine dust in the air which looks messy but it matches the relatively untidy shop too! I also weld and grind in the shop from time to time but dont use the extractor until I sweep up at the end of a job and all sparks are well and truly cold.
I didn't explain very clearly: I have a two bag 1HP Kity extractor and plan building a small "sealed" area in the workshop to house it and then to use a kitchen extractor to vent this "sealed" area to the outside. The kitchen thing is only to get the fine dust that escapes the top bag to the outside world. I did something similar at the last house and it worked well. The difference now is that I'm thinking of running ducting in the ceiling rather than hoses over the floor.
I realise now that I didn't tell the whole story - I use an old Dyson or Combivac for the router, scroll saw, etc. and either a 3M 4251 mask or a JSP powercap when I can be bothered (which isn't as often as it ought to be). My chip collector is only 1HP so I'm concerned about whether it will have enough umphh to cope with ducting - I've just used corrugated
4" flexi on the floor before but this is quite dangerous.
I'll follow-up on the cyclone links - knowing what you now know, do you think it's worth the effort of building a cyclone?
I knocked up a Cyclone separator ... does 100% what it should do ...... Thought about spending Hrs making one out of wood or metal in the end I bought one of these:
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Fitted it to one on these
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and with some vertical supports used this to make it all mobile:
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If you want details or a pic - happy to provide.
IU now use the house central vac - with no fear of a load of wood chips or sawdust blocking the pipes.
It is great to see the chips spinning around the unit,and dropping into container - very efficient.
Yup I had the same problem - hence the length of soil pipe overhead to mitigate. The soil pipe offers less air flow resistance that the flexi pipe - so its better to do as much of the run in that as you can, and just use the flexi for the final connections to the machines and extractor.
I would say a powerful cyclone (with exhaust filtration) is the way to go for the big machines - especially if you are venting the exhaust air back into the shop. Whether you build or buy will depend no how cost sensitive you are. There are a number of self built cyclones out there on youtube that seem to function well.
I run mine most of the time I am working just to keep the airborne levels down. (and in the winter it tends to blow some warm air down from higher up in the shop to where I can feel it!)
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