extracting mdf dust

[prawnking]

this discussion is great i am relly begining tounderstand a lot more about dust extraction, but still not sure if i should build or buy.
there is a link from bills website to a company producing plastic cyclones thinking about a mini one, does any one know if you can buy them nearer

barry how did you build yours any chance of some pics

i am thinking it might be good to use a camvac like jake recomends with a mini cyclone any thoughts.

anyway dust extraction is turning out to be a much more complicated subject than i expected, would have thought manufacturers would of put a bit more money to designing a good extraction system for the small workshop/hobbiest, there does seem to be a lot of godd woodchip collectors out there but not a lot of very fine extractors which in my opinion is more important

o what do i do?
decisions decisions? not used to having to make any wife does all that for me LOL (only joking shes levely really)

 

[nickson71]

Hi Prawnking

Here is a Link to one of the step by step Pentz cyclone builds

You could use pop rivet and sealer rather than welding or you could get a local pro metal workshop to give you a price ..... when I have time I'm going to make my own using the riveting option as I've never welded before

Also as far as I how there are no hobby cyclone available in the UK and the shipping + duty for one from the US make them very expensive

 

[Nick W]

Has anyone seen these? They sell various bits including just the cyclone, which would get around the motor problems. Just need somewhere to buy a UK speeded impeller.

 

[Jake]

Jake
I tested a total of 7 vacuum cleaners with both of my mini cyclones. I started with a 600W B&Q shop vac upto a 2000W and included two different Dysons.

So these were domestic vacs? Maybe take a look at a Camvac's motor the next time you are at a trade show -ask them to lift the lid and show you. You couldn't fit one in a Dyson - they can't be far off the size of a Dyson's cyclone chamber for a start, and would be far too heavy. The analogy just doesn't work - these are serious motors.

What I was trying to do was to separate the maximum amount of dust out of the air and allowing very little to get through to the vacuum filter as their filters are too small to be of much use.

Makes sense giving what you were trying to achieve with the types of vacuums you were using - but the camvac is built to do this without such outside help.

I went back each time to attempt to improve the cyclone separation. The 2000W achieved the best results and as that was the largest domestic vacuum I could find I started on the extractor route.

I'm really not surprised that domestic vacuums failed the test of becoming a home workshop chip and dust extractor. I wouldn't be standing up for a Dyson's ability to do that task. Hell, I have a lovely festool dust extractor that is faultless in that role, but I wouldn't begin to pretend it can work as a full-on chip and dust extractor for machines rather than power tools.

I tested a 1, 2 & 3HP extractors with the idea of preventing as much dust and chips as possible from reaching the extractor... Its now time to concentrate on dust separation and the prevention of most dust getting to the filter so back to the cyclone approach

As I've said this all makes sense given the low pressure route you chose to take - in which the filter has to be protected from clogging to avoid increasing resistance and consequent sharp falls in flow rates and volumes. Much less of a concern with a HP extractor, where the resistance is much more easily overcome, with vastly less consequent effect on flow rates and volume.

I bought a clamp meter after reading Bill's site

Yeah, I just read a section where he mentions the use of them - he seems to be concerned with avoiding exceeding the maximum duty cycle than anything else, unless I missed something?

If that is the case, I'm just going to trust Camvac to have specced their motors properly - they do say to turn them off ten minutes every hour or something, but that's never been a problem. I wouldn't operate a machine constantly for 50 minutes anyway.

and for flow rate tests I use a bucket of mixed chips and fine dust and time the rate to empty the bucket

Wanna bucket race?

Hope this helps as I did not set out to prove one was right or wrong but to just improve my lungs. Barry

Yes thanks, interesting stuff - and we all have the same end in sight. I'm not trying to say anything is right or wrong either. If I could have had an HVLP machine sited outside the workshop, with big ducting (and ideally redesigned 6" outlet collector hoods) I would have gone that route - cheaper and quieter being two good reasons.

I just think there's more than one way to skin a cat here, and Pentz's approach and figures are built on HVLP assumptions, which makes sense as it is a far more standard, universal and scalable approach.

Camvac kind of sneak around the side a bit, that's all I'm really saying, being something of HVHP, or MVHP perhaps, approach. The high static pressure means that Pentz's total focus on resistances, at the machine's collector hoods, in the hoses and pipes and in filters, doesn't really apply in the same way at all.

I don't know whether a camvac could in fact 'pass' Pentz's fundamental basic requirement of

50 FPM over roughly a 9” radius

at the machine collector hood, from which he appears to derive everything else. I'm just saying that the stats and requirements he sets out can't be used to write off the camvac, as they are based on the wrong values being inserted in the formulas he uses (which aren't clearly set out) - they would need to be recalculated using the right values for air-speed, air flow and static pressure.

Cheers, Jake

 

[gardenshed]

I got CamVac HQ tech dept to check if their machine was suitable for planer thicknesser use and they said yes if you have the 4" outlet fitted and a twin motor. After 2 months of constant blockages and filter changing I gave up and after a lengthy dispute they finally agreed that their machines are not suitable for planer extraction & I got a full refund plus compensation.

CamVac stated that I should never have been sold the machine for planer thicknesser use as it's main purpose is fine dust and loose debris ie cleaning the shop floor and works best with a 2.5" outlet ( which is no good for chippings).

I now have the Scheppach 1100 CMH with 0.5 micron pleated filter and what a revelation compared to the CamVac it does everything I want and it's a hell of a lot quieter too.
I use a small Trend VAc with power takeoff for my router & Metabo sander which is excellent at MDF dust and again it's quiet too.

 

[Jake]

I got CamVac HQ tech dept to check if their machine was suitable for planer thicknesser use and they said yes if you have the 4" outlet fitted and a twin motor. After 2 months of constant blockages and filter changing I gave up and after a lengthy dispute they finally agreed that their machines are not suitable for planer extraction & I got a full refund plus compensation.

CamVac stated that I should never have been sold the machine for planer thicknesser use as it's main purpose is fine dust and loose debris ie cleaning the shop floor and works best with a 2.5" outlet ( which is no good for chippngs).

My three motor works effortlessly on my hms260 planer thicknesser (with all three on). There is a massive step down from three to two motors. I've never had a blockage, and the filters are fine. Planer thicknesser is what I mostly use it on.

Edit: I'll try it on two and one motors next time I'm using the planer thicknesser to see whether I can replicate your problems - if so that's definitely something people should know about.

 

[gardenshed]

My three motor works effortlessly on my hms260 planer thicknesser (with all three on). There is a massive step down from three to two motors. I've never had a blockage, and the filters are fine. Planer thicknesser is what I mostly use it on.

I should have mentioned in my prev post that CamVac lent me a three motor version & they even delivered it and set it up, after about 15 mins it was back to the same problem as I described earlier, the chap went away red faced. And what a racket 3 motors make :shock:

 

[Jake]

What PT was this on?

Bizarre - I really haven't had anything like this on mine - not even a hint after a long thicknessing session.

Edit: In fact, I fail to see how it could happen on a properly functioning machine unless you jammed it up with solid bits of wood for the shavings to catch on - there's just too much suction for shavings alone to jam the hose.

 

[prawnking]

hi gardenshed
i am sure that most workshop vacs and dust extractors will draw mdf dust away from the workpiece but how sure can you be that the fine dust below 2.5 microns is not being blown back into the air

have you checked out bill penz website
http://billpentz.com/woodworking/cyclone/Index.cfm

it turns out dust extraction is a lot more complicated than just cleaning up visable chips and dust and it also seems most manufacturers over rate their equipment and filtering.

i think a cyclone design might be the way to go but dont think i got enough room for one the size that bill recomends let alone the fact of having 6" ducts all my power tools have approx 30-50mm outlets on the extraction ports which i believe fail the criteria for his designs

still pondering, i want to build/buy one soon so i can work safely without the helth worry.

cheers

shaun

 

[Scrit]

...anyway dust extraction is turning out to be a much more complicated subject than I expected, would have thought manufacturers would of put a bit more money to designing a good extraction system for the small workshop/hobbiest, there does seem to be a lot of god woodchip collectors out there but not a lot of very fine extractors which in my opinion is more important

But just how can they? That's the problem - there is no simple one size fits all solution to this as an extraction system ideally needs to be sized to its machines, chipload and trunking. And MDF potentially requires a different approach to solid wood waste. The other downer is the need for EU manufacturers to meet a set of regulations called the "ATEX Regs" which involve destructive explosion testing of their products - expensive when the average fly-by-night Chinese import doesn't seem to undergo that.....

One European company who has got a good small shop system is Felder, with its RL125. That machine has the capacity to extract fine and coarse chips and filter out properly into a drop box, but it comes with a pretty steep price ticket of over £1500 (I think). I believe the filtration in that machine is an inverted multiple-envelope system similar to the type ised by companies like DCE (Dust Control Equipment). You can get pleated filters for both Felder cyclone/bag chip collectors and for some of the Jet range, and whilst these are an incomplete solution they do seem to be a lot better (cleaner) than the felted bag filters and for a small shop they seem to be a cost effective way to improve DX, especially if coupled with better quality (and larger diameter) ductwork.

Scrit

 

[prawnking]

hi scrit

what sort of dx system do you have or what would you advise :?:

i am really looking into this as i havent got any sort of extraction yet so i want to get the best that i can straight off (only just finished building workshop few months ago).

 

[gardenshed]

hi gardenshed
i am sure that most workshop vacs and dust extractors will draw mdf dust away from the workpiece but how sure can you be that the fine dust below 2.5 microns is not being blown back into the air

The CamVac I mentioned the makers claimed 0.5 microns.
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, and then going into the workshop the next day and all the dust that was still in the air the day before had settled everywhere you looked.

have you checked out bill penz website
http://billpentz.com/woodworking/cyclone/Index.cfm

yes, many times

 

[ivan]

At the risk of teaching grandma, the first thing is to think about the machine and the qty/type of waste it's producing. Most folk won't be putting mdf over a planer so it's typically producing large and light shavings, and with a proper extractor hood, so a relatively modest air flow (3-500cu.ft./min according to planer size) is OK. The planer doesn't care if this comes from a 3 motor Camvac or a 3HP bag system.

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. In general, the finer (and more dangerous) the dust, and the more dificult to fit a hood , the more cu.ft./min you'll need for that machine. There's some useful data on this which agrees with Cyclone Bill on the HSE website. (free publications, as .pdf) Decide how many cu.ft./min you need, next how much ductwork, and then the extractor.

A 3 motor Camvac maxes at 300cu.ft/min so is OK only for smaller machines with good hoods and easily extracted waste. Where it wins over HVLP extractors is in its ability to suck the 300 cuft/min through a smaller pipe. This may be essential for eg. in top and botton extraction from a big router, or the top gaurd outlet from a sawbench, and its fine filtration will be helpful if you're concerned about meeting HSE air specs. 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.

 

[ProShop]

One European company who has got a good small shop system is Felder, with its

Scrit

Oooohhh did someone mention my name .

Now that's what I call an extractor Scrit, it sucks at 3000 cubic metre an hour and is Certified down to 0.3 microns that's cleaner than the air we normally breathe. And at £1500 (used to be 2K last year) I think it's good value when put up against the competition. Felder call it and it's mate the RL160, Clean air dust extractors.

On a smaller scale they also do the AF22 which also sucks at 3000 cubes and filters to 0.5 microns for under £600 now that's imho good value.
There's another the AF10 which is 0.5 micron and sucks at around 1500 cubes and is very good for smaller machines at around £300 which again imho stacks up well against the competition.

The RL series will suck a house down, at last years open day some stupid Pil**"!%^ put his hand inside the 140mm hose

 

[ivan]

Barry, thanks for the ebay cartridge filter link. Was there a particular reason for choosing this one? (RB industrial list more than one cannister).

Scrit's link to the Felder may be more helpful to potential constructors. Barry's ebay link to RBIndustrial shows this seller is currently offering a multi pockekt bag for ~£100 (14 sq.m. Spencer Halstead Pangbourne 14pocket, multipocket Filter Bag, 350gsm polyester needle felt media, for use with fine dusts. The finish is superglaze which ensures that fine, dry dusts will release readily) It would be much easier to make up a box for this filter, Felder style. 14 sq. m is about 150 sq.ft, and with a target airflow thro' the filter of around 6-7ft./min (to catch, not leak, dust) it should cope with a maximum actual flow of 7x 150 about 1000 cu ft/min. You could easily rig up a manual shaker! Strictly speaking both this and the cyclone should have some explosion relief built in. The paranoid could put a cartridge on the outlet...

When you remember that air/dust is rushing toward the filter at (hopefully!) 4000 ft/min you can see why a standard bag leaks dust. Sorry for mentioning HSE again (they're not paying me for it) but they do have some good free/very cheap publications on this subject with useful data good enough to help improve things diy style over a single felt bag.

Observations, please, as I'm thinking multipocket may be the easiest route if you're not making dust all day.

 

[Barry Burgess]

Ivan
I chose that filter after some discussion with them as I wanted another filter that they did not have and the price from Donaldson's was £115 +VAT + delivery and they would not sell it to me unless I had an account and would be a regular user of filters.
The Jjapanesesite showing a cyclone build also uses the Donaldson filters but he had a friend in the USA who bought from Donaldson and another friend in the US forces so the filters were flown to Japan as the price was just short of £200 and a three month delivery.
Two are sitting on top of my 3HP extractor at present with a much uprated suction over the bags.

Jake I will take you on with your 3 motors and the dustbucket test with my 6" pipe verses your 4" . Better still attach your canvac to my ducting system and do the test??
Jake I started out with dedomesticacuums like most of us did when we just had a few hand tools

Sorry about the request for pictures but I have not got a site to put them up on so send me a PM with your email address and I will forward them.
Stev's site in Japan is very good on the cyclone construction
Barry

 

[Scrit]

Decide how many cu.ft./min you need, next how much ductwork, and then the extractor.

I could not agree more for a fixed environment, however for a home workshop without a fixed ductwork system that simply can't be done, so probably the best thing to aim for in that case is an extractor which will keep the top of your machine clean, won't choke on the planer shavings and will give reasonable performance on sanding - that or employ a vacuum cleaner for the sanding as a separate unit.

When you remember that air/dust is rushing toward the filter at (hopefully!) 4000 ft/min you can see why a standard bag leaks dust.

Observations, please, as I'm thinking multipocket may be the easiest route if you're not making dust all day.

The DCE industrial extractor we have on our pin routers, the panel saw and the CNC router (all fine dust producers) is a 4.4kW (6 HP) machine with a plenum chamber and drop box beneath the filter envelope, our extractor is a bit bigger than the one you mentioned and we got a replacement filter set from a local firm (there's 4 or 5 around Manchester). I chose a cotton/PTFE mix to reduce sticking of MDF dust, however, if you do go multipocket than remember that the chamber around it will be fairly large (our machine is around 9 ft high) and you'll need to incorporate an explosion relief vent at the top with the blast directed away from the user area (yes, really) as it starts to become an issue with machines of this type and size. Even the smallest 1HP DCE and Mardon units incorporate a relief vent or panel for safety. Another thing you'll need to incorporate is either a shaker mechanism or back-pressure (air) cleaner of some type to keep the filter area from clogging - I routinely stop the unit and shake-out every 2 hours or so which equates to around 1/2 to 3/4 cubic metres of dust on a busy day. This is incidentally the most hazardous part of the operation (more dust within a given volume = potentially explosive mix) and the galvanised steel body of the machine has extra earth straps to try to ensure that any static is dissipated. This extractor works really well with fine dusts from MDF, chipboard, sawing, etc - for example we can run the CNC and a pin router simultaneously - but it's very poor at handling larger shavings as the drop box is inadequate and the filters tend to clog and not release the shavings all that well. The drop box is also way too small for the shavings I can produce in a 30 minute session on the P/T so to handle that I use a conventional Coral bagger unit with finer and larger filter socks fitted than standard.

If you want any more details, please ask.

Scrit

 

[Scrit]

The CamVac I mentioned the makers claimed 0.5 microns.
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, and then going into the workshop the next day and all the dust that was still in the air the day before had settled everywhere you looked.

I think that with this quote we're starting to get somewhere near. A bagger chip collector will still put out an appreciable amount of fine dust - with fine enough filters not enough to have you coughing but none the less enough to cause concern.

This tends to make me think that a good general purpose machine for sawing and planing might well be something like a 2HP bagger cyclone fitted with a dustbin as a drop box and with either an oversize 0.5 to 1 micron filter sock or better still a 0.5 micron pleated filter unit instead. That and possibly consider having a small high-pressure low-volume system for attachment to to portable tools. The ductwork, etc can come later, if at all....

Scrit

 

[Barry Burgess]

This tends to make me think that a good general purpose machine for sawing and planing might well be something like a 2HP bagger cyclone fitted with a dustbin as a drop box and with either an oversize 0.5 to 1 micron filter sock or better still a 0.5 micron pleated filter unit instead. That and possibly consider having a small high-pressure low-volume system for attachment to to portable tools. The ductwork, etc can come later, if at all....

Scrit

I use a mini cyclone attached to a vacuum (2000W) for my small high pressure system using 1.5"pipes and use the 3HP extractor with two 65litre drop bins to aid the separation. The 2HP loses flow with one drop bin while a single drop bin on a 3HP does not retain anything. A 44gal drum would be better as a drop bin on a 3HP motor. The two 21m2 pleated filters that I fitted this weekend have made all the difference - no fine dust and much improved suction.
The cyclone when complete will prevent even more dust from getting to the filters - which I think is the main point of the all this trouble taken????

 

[ivan]

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.

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.

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.

I would guess from the photos and info on ebay a 2HP multipocket drop box and filter could be built in a space less than 3'x3'x8', probably similar footprint to cyclone but much easier to make.