Dust Extraction for small workshop

[Matt Helliwell]

Bit of a common topic I know but I could do with some specific recommendations. I've got a small workshop (about 3mx4m) at the back of the garden and I need to improve the dust extraction. Currently I've got an old Vax which isn't up to the task.

Now is there any reason I can't vent the dust straight outside rather than messing around with bags and filters? I'd have to open the windows to let in clean air but as its not heated I could live with that. Also, I don't think the dust would get in anybody's way either.

If this plan is workable, what sort of dust sucky thing do I need? Most of the dust is from routing, light sanding and the radial arm saw. Noise isn't a huge concern, but price, of course, is.

Thanks

[Peter Ashby]

Agreed. If the Vax is truly knackered then look at either the Wickes version of the Earlex combi with power take off or B&Q's new PPro extraction models, again some have take off. I have the Earlex with takeoff and its suction is great though it is a touch noisy. Some time soon I will build it a cyclone to separate out the big stuff from the fine. Cutting dadoes with the router is SO much easier when you have extraction fitted that switches on with the router and off a while after the router. No more dadoes clogged with dust, and no more fire risk.

I bought the Earlex after a marathon session handheld routing rebates on a load of 18mm ply, I went in the next morning having recovered from being totally covered in dust and saw a 6" long scorch trail in a pile of dust where a spark had smouldered its way along in the night and, fortunately, not ignited properly. Faced with the garage going up in smoke SWMBO needed little persuasion that the expenditure was necessary. The state I was in when I had emerged from the garage the previous evening also helped I think.

Peter

[Peter Ashby]

I got my wide hose from the bargain bin at B&Q for less than a fiver. Thanks for the tip about the exhaust, I'll try that. Also thanks for the info that it's good with a cyclone.

Peter

[Andy Dingley]

I get _no_ dust in the vacuum. The cyclone is that efficient. Well, the tall one is - the older one let some dust through.

If I rout MDF, then I get a fine dust cake forming on the filter (the upgraded pleated one). Even then I don't get any build up in the cleaner's bucket. If I'm working hardwood, then I don't see dust collected at all. The only time I ever need to empty it is if I've used it "bare", to sweep the floor.

[NJF]

I agree, had a problem dust that we needed to keep out of the toxic vac, made a tub cyclone and 99% gets caught in it, the 1% might be caught by a taller unit but that won't fit in the location. We've also got a Record 3 motor extractor that could do with a cyclone, but as space is a big problem we just change the filters regularly, get those wrong and it stops working as the dust (mainly graphite) shorts the motors out....

Niel.

[Nick Nelson]

There's a balance to be struck between the volume of air you can move, its velocity, the pressure it will suck against and the size of the particles it needs to carry.

The vacuum cleaner (henry/vax) type of arrangement will move modest amounts of air at high velocities and pressures, but won't work too well with large bore pipes.

Workshop extracters move lots more air, but don't work well against large pressures and so are less satisfactory will smaller pipework.

I developed mine four or five years ago initially using an Earlex, but moved on to a bigger dust extractor.

system is based on 4" ducting and flexible pipework.

Whats really good about this whole issue is that it's so interesting and easy to simple experiment with different approaches, starting from what you happen to have already in terms of materials and blowers, and develope it into a system which works for you.

Nick

[Peter Ashby]

Axminster sell a lid for a plastic dustbin with ports on the top as a cylcone. I've not tried it myself but am tempted to do so. Might be the easiest option.

Peter

[Andy Dingley]

I'm not too keen on this gadget, although I've not tried it.

IMHO, it's a drop-box, rather than a cyclone. Probably works well for thicknesser chips (my biggest DC problem), but it won't stop dust. There's no central tube to keep the airflows separate and so the separation efficiency will be poor. It's also quite shallow.

I don't think a dustbin is the best start for a cyclone. It's too short and squat, and it's huge. I need the workshop floorspace more than I need that sort of storage volume. A tall, narrow cylinder of the same overall volume gives better proportions for the cyclone aspect.

[Gnube]

Take Care, Gnube {too thick for linux}

[Woodspoiler]

I made one, as I posted a while back in response to the original thread.

I then didn't use it much, as I was landscaping the garden, but over the last two weeks I have been building a wardrobe which involved a lot of routing and cutting, mainly MDF, and I also used it to clean the workshop floor and bench.

I have made or bought fittings which hook it up to a jigsaw, bandsaw, router, router table, plus I adapted the original vacuum cleaner tools to push onto the end of the hose for general cleaning witin the range of the long hose I bought from Axminster.

Result was 50-75mm of densely packed dust evenly distributed over the bottom of the cyclone bin (it's a plastic 55 litre £5 dustbin).

The first vacuum cleaner bag developed a hole but between it and its replacement I only got, say, four tablespoons of very fine dust.

At that rate one bag would last a very long time, but the paper seems to weaken in use and I think a burst is more likely than a full bag. Maybe the pores in the bag clog up making a burst more likely,

The only siginficant problem is if the hose gets blocked, either with a large and coarse plane shaving, or because I put the nozzle too close to a surface when using it for general cleaning up, the suction is enough to partially collapse the bin to a three-pointed cross section.

After this happened a few times a split developed at one of the peaks. I taped over it and am more careful now, but the finishing touch would be a pressure relief valve which I will make as soon as a spy a suitable spring.

W.

[stefek.zaba]

And how long before that nice Mr Dyson asserts his patent against you? ;-)

[Nick Nelson]

I had exactly this problem in my early experiments. It can be solved by using a galvanised steel dustbin instead (assuming you can still find one of course).

Nick

[Nick Nelson]

Fortunately, cyclone separation was a common industrial techique well before Mr Dyson was born.

[stefek.zaba]

It was indeed, which makes his current whingeing on about how Inventive he is, how expensive patent renewals are, and all the rest of the Great British Inventor pose, get right up my nose (vortex-free due to blockages ;-)

Stefek

[Peter Ashby]

If you do, a post of the valve would be appreciated. Some of the dog holes in my bench are necessarily blind and so need vacuuming out on occasion which might cause the problem you see.

Peter

[Nick Nelson]

How about using one of the small door catches which have two spring loaded ball bearings pressing into the sides of the catch plate. The better ones of these are adjustable for tension. atmosphere _____________________ ______________ _____________________| |_______________ hinge O_||____________||____ || vacuum side |_____________________|== catch ||

I suppose it wouldn't be self resetting though.

Nick

[Gnube]

You're confusing me with someone who actually gives a damn about being sued - you can't strip an already naked man! :O)

Besides, it's going to be (sometimes) used with a Dyson! A nice way to treat a paying customer that would look!

As a matter of fact, I'd be deeply appreciative of the opportunity of a "face to face" with Dyson in a legal setting too; I have a bone I'd rather like to pick (until it's truly clean and shines) with them! ;O)

Take Care, Gnube {too thick for linux}

[PoP]

on the vacuum hose? I had that problem with an old Aquavac - whilst sucking up sawdust the plastic (or nylon?) pipe would gain a static charge, which could cause an interesting reaction when you came to touch something that was earthed :)

Solved the problem by connecting an earth wire to the vacuum hose. Ever since I've been cautious with any form of vacuum arrangement, just in case.

PoP

[Woodspoiler]

In response to various posts:

Galvanised bins: good idea. I'll look into that if I destroy the plastic one.

Static: never noticed any! Maybe using hose designed for dust extraction has helped. I got that and the step-down adaptor to connect to my jigsaw from

Mesh on inner bucket:: blockages occur in the inlet hose between the business end and the cyclone bin, so that wouldn't help.

Spring catches: neat idea, but crude and involves spending money. This is a low budget project and I'm using found items where possible.

Screwfix springs: hadn't noticed they sold them, but I think that's the wrong sort of spring (my valve idea requres the spring to compress and push back, rather than stretch and pull back)

A ferret around my garage has turned up a suitable looking spring. It looks like the return spring from an ancient car or bike throttle linkage (or perhaps brake or clutch). It fits nicely up a bit of scrap copper pipe I have, so all I need is to cobble together the valve end.

I shall post back when I've got someting usable, but the plan is to have a lip at the bottom of the pipe to retain the spring but allow air through the pipe. The spring will be compressed inside the pipe. The inlet end will be like the outlet, with the addition of a plastic or rubber disk. This will be sucked in whent he pressure is great enough, and allow air in.

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[Woodspoiler]

Sorry, hit the wrong button before finishing the ASCII art. This is my plan for the valve design. View in mono-spaced font like Courier.

Atmosphere

-- -- lip to retain spring and form seal with disk |===========|

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inside