extracting mdf dust

[Anonymous]

The Scheppach I have now claim 0.5 microns, and to be fair I have a virtually dust free workshop, when I had a 2 micron chip extractor there was fine dust everywhere, especially after cleaning up

This has been my experience with the Charnwood chip collector too. I fitted a 0.5um bag from Axminster and the garage environment was transformed

 

[Barry Burgess]

Barry, are you presently using two canister filters with plastic bags/bins underneath - effectively a dual filter on top of a drop box? How blocked up do those filters get? could they relace a multipocket bag filter? (see below)I know the cyclone is probably best, but is much more difficult to make..

No I have two 65 litre bins in the system before the extractor. The first uses a 90 degree elbow to create a 'cyclone' type effect and gets the large chips, general rubbish and other things that you vacuum up. The second has a board that divides the input from output and goes about half way down the drum when it gets to the extractor which has two separate dust collectors and above each there is a filter. The lower bags (drop bags are plastic) . I made MDF rings the size of the top of the extractor with a hole cut in that is the inside diameter of the filter. A good amount of dust is settling under the MDF ring.
Hope this help else PM with your e mail address and I will send pics
Barry

 

[Scrit]

Scrit, even just a flexible hose reduces suction, on the smaller mobile units, perhaps by half - I guess that's why Bill says don't use 4" hose/pipe.99.9% of units give the cu ft./min with no pipework ar bag attached.

Yes, I know, but if you are starting out in this it may be a price you need to pay in the short term - ductwork costs money so the best thing to do is keep the flex hose as short as possible. One thing I do hate is having to recalculate the ductwork every time I replace/dispose of/introduece a machine. :twisted:

Are you thinking about extracting through the impeller then blowing out through the envelope filters? I thought that you would be doing it the other way - extracting through the bags - as that way you can go for a aerofoil impeller (fan) which will be considerably more efficient that the standard plate impeller. Hence the nature of my last post.

The apparent advantage of a multi pocket bag over a cyclone, if you have a leaky bag type extractor already, is lower resistance, and thus suitability for the smaller 2-3 HP extractor.

To be a pedant it's really the advantage over a sock filter..... I would think, though that having a cyclone in front of your drop box and plenum/filter would allow you to use the extractor for both fine and coarse materials - the cyclone would spin out the heavier stuff such as the planings into a separate drop box leaving the filter envelopes to handle only a relatively small amount of fine materials.

BTW, for anyone who's never seen one, this is an envelope filter and this a DCE-style fine dust extractor. The envelope is within the body, there is an explosion-vent on top and the fan is an aerofoil drawing through the filter envelope. The interior of this style of unit can be seen here

Scrit

 

[Jake]

Take something more awkward, like a horizontal sander, when extracting 500 cu ft/min at each end (three triple motor camvacs!) will not capture all the fine dust.

But neither will any standard hobby machine - if you can be arsed to build a cyclone and your own big impeller, with big ducting, or buy the £1.5k Felder or something, then you stand a chance. Not sure I'm that obsessed with it, frankly.

A 3 motor Camvac maxes at 300cu.ft/min so is OK only for smaller machines with good hoods and easily extracted waste. ... The underside of the saw will still need a high vol/low press extractor on it. Thus, I believe the Camvac is a bit of a niche product.

Nearer 350 than 300, for what difference that makes. I think it depends on what machines you are using - Pentz's figure are based on US saws where dust extraction is an afterthought. Euro-built machines tend to be much better on the dust extraction front - as Pentz himself laments.

I think the camvac is a convenient alternative in a hobby workshop, and I wouldn't put it any higher than that. It offers enough throughput for most types of machine, especially if they are smaller machines with 4" or smaller hood outlets where the apparent free-air cfm shortfall is going to be wiped out in short order.

The HSE will be focusing on industrial size machines - if you can afford and are using them then go for a full on Scrit-style system - that's a whole different league.

 

[prawnking]

so whats recommended for a workshop of 20 * 7 feet with
table saw (30mm extraction outlet)
scms 30mm extraction
thicknesser 100mm extractor,
router, belt sander, orbiral sander, electric hand planer
and soon jointer and bandsaw.

i know its a difficult question
i was thinking along the lines of trend t30af and a chip collector
self built cyclone mmmm not sure
or a camvac as long as it would collect by chips from thicknesser

any other sugestions r welcome
cheers
shaun

 

[DaveL]

Barry sent me some pictures of his current setup, here is a general view that shows the drop bins and the filters.

As they say a picture is worth a 1000 words.

 

[Barry Burgess]

Prawnking
Start by making 100mm ports for all your machines - PVC piping and a heat gun can make most things - It helps if you visit Europe as the 110mm UK soil pipes don't fit. Most of my ports were 32mm and it took some practice making the table saw guard and the router table port but in the long run PVC and a heat gun and practice make most things.
The 30/32mm ports will only work with a vacuum cleaner.
Barry

 

[ProShop]

PrawnKing,
If you don't fancy making your own, then I'd look at the Felder AF10 It's similar money to the CamVac and more powerful, it'll suck half a house down and 0.5 m filter, and then a small say Trend for the small power tools, sander etc.

But if you fancy making your own I'd talk to Barry B nicely he's built one that really sucks

 

[Barry Burgess]

Thanks Dave - I must get out of the workshop and find a site to post the pictures - my words don't always get the point across
Barry

 

[Barry Burgess]

PrawnKing,
If you don't fancy making your own, then I'd look at the Felder AF10 It's similar money to the CamVac and more powerful, it'll suck half a house down and 0.5 m filter, and then a small say Trend for the small power tools, sander etc.
But if you fancy making your own I'd talk to Barry B nicely he's built one that really sucks

Half the fun is making your own - and all the mistakes - in the end you will get there - I hope
Barry

 

[DaveL]

Barry,

I have started to use Google as a host for pictures, its free, will produce thumb nails automatical and will upload via a web page you don't need an ftp client. Look here.
If you don't have a google account I have some invites, ask and I will send you one.

 

[DaveL]

Half the fun is making your own - and all the mistakes - in the end you will get there - I hope

Barry is on the mark here I made a cyclone to the planes from Wood magazine from across the pond.
If you look here you can see the making of my cyclone and here for the blast gates and start of the pipe work.

 

[prawnking]

daveL
do you have a copy or a link to the plans

if i was too make my own i am pritty confident about the metal work for the cyclone unit but not to sure about the blower fan
so
would one on these do
http://www.machinemart.co.uk/product.asp?p=060610035&r=2128&g=116

if mounted to the cyclone top somehow

cheers shaun

 

[Jake]

so whats recommended for a workshop of 20 * 7 feet with
table saw (30mm extraction outlet)
scms 30mm extraction
thicknesser 100mm extractor,
router, belt sander, orbiral sander, electric hand planer
and soon jointer and bandsaw.

i know its a difficult question
i was thinking along the lines of trend t30af and a chip collector
self built cyclone mmmm not sure
or a camvac as long as it would collect by chips from thicknesser

any other sugestions r welcome
cheers
shaun

First question is whether you can stick an extractor outside and duct it in to your workshop - if so that is the quickest and easiest and cheapest way to go. You'll need a shop vac as well.

If you can't, you have a choice of getting a pleated filter on a HVLP vac and a 'shop vac' as well for the power tools, or investing the time and effort into a cyclone set-up like Barry's and a shop vac for the power tools, or you could get a camvac (and no need for a shop vac as well).

There's no right answer, it depends on your priorities, and more than anything probably the balance between your budget and the demands on your time.

 

[ivan]

Barry, thanks. I can see now from the posted pix. Do the pleated canister filters load up much? quickly?

 

[Barry Burgess]

Ivan I just completed fitting the filters this last weekend so in a week or so I will remove them to see. A good portion of the dust is being stoped by the O ring(MDF) at the bottom of the filter as the inlet is the same diameter as the id of the filter.
Barry

 

[Barry Burgess]

Barry,

I have started to use Google as a host for pictures, its free, will produce thumb nails automatical and will upload via a web page you don't need an ftp client. Look here.
If you don't have a google account I have some invites, ask and I will send you one.

Please Dave I have not got a Google account

 

[ivan]

Thanks for that, Barry. Also, I wonder, do you know from your chat with the supplier what the filter's made of? "blotting paper" like a vehicle filter? Plastic coated to aid release of cake? All plastic? (our Alto vac has a 0.5 filter all plastic, washable, and virtually tearpfoof - I couldn't damage the one on the exhibiyion stand)

 

[ivan]

Extracting from small machines:
My bag (sock filter) extractor is rated with bag (new,clean) and 6' of 6" flex hose, at 1200cu.ft./min and it barely captures all the dust made by the 10" RAS, which is hardly gigantic. When it gets a bit caked up flow is much less and effective extraction worse. The same applies to an Axminster horizontal belt sander. The bandsaw is clean if you extract from additional diy bottom rear, as well as just under table. There's no problem with the planer.

The extractor's in a corner of the workshop. The felted polyester sock is about 2' in diameter x 5' tall. (about 32 sq') Airspeed through the filter medium is therefore about 38 ft/min. My understanding is that polyester felt will only trap the finest particles when the speed through the filter is 3-4ft/min or less**. No doubt a bigger filter is needed! About 10x bigger!

I first thought of just adding extra (sock) filters to reduce the amount of dust coming through the filter felt, but quick calculation shows it takes up FAR too much room. Mods. had to be based on multi pocket felt or a cartridge, whichever was likely to be easy to icorporate and keep reasonably cake free.

The Q is, what can keep the bigger filter relatively clean- simple drop box or tricky to make cyclone.....

One might think the published info is based on huge industrial machines, but the illustrations show otherwise. Moreover their figures agree with Bill's website, and he didn't base his findings on heavy industrial machinery either. Also, they are both talking about removing as much dangerous stuff as possible to protect health, and not just keeping machines visually clear of waste.

** 6-7ft/sec for old fashioned sawdust

 

[Jake]

Extracting from small machines:
My bag (sock filter) extractor is rated with bag (new,clean) and 6' of 6" flex hose, at 1200cu.ft./min and it barely captures all the dust made by the 10" RAS, which is hardly gigantic. When it gets a bit caked up flow is much less and effective extraction worse.

How big are the ports on the RAS? I don't have one so I can't try it, but my father's deWalt has a 2" max dust outlet on the guard. A LP extractor is going to pull naff-all through, comparatively, through that. Pentz's text makes it clear his CFM requirements take such machine limitations into account (although one of his other tables has a conflicting note that it relies on all hoods being replaced, presumably to a 6" bore, although how you'd get that on a RAS guard and have much guard left I don't know.).

The static belt sander I doubt the camvac could cope with to the standards you are setting - or any other domestic extractor.

One might think the published info is based on huge industrial machines, but the illustrations show otherwise. Moreover their figures agree with Bill's website, and he didn't base his findings on heavy industrial machinery either.

Well, for instance, his planer figure is for a planer up to 20" - twice the size of mine. To maintain the same airspeed for the same distance from a duct twice as long requires how much more CFM?