Will I need a cyclone?

[goldeneyedmonkey]

Hello all,

I'm going to be moving into my first workshop in about 8 weeks. It's going to be about 16ft x 16ft (ish).

Equipment will be: Table Saw, Planer/ Thicknesser, Bench Top Bandsaw, Router Table, SCMS. Plus all the usual handheld powertools: Router, Jigsaw, Circular, Drills etc.

My question is will I need to get a Proper Cyclone System sorted (£1400 ish from Axminster) or will I get away with a few more mobile dust extractors and a couple of the Jet Workshop Air Filters?

What are the pro's and cons?

I'd much rather have the cyclone, but with just starting out in business I want to keep start-up costs to a minimum.

Cheers for any info, _Dan

 

[Chems]

If I was starting all over again I'd definitely get a cyclone. That was easy to empty. I did have a Festool Vac, Jet Air Filter and 5 micro filtration on the 100mm extraction unit and although a good combination I still got a fine layer of dust all around the dust extraction unit.

 

[Hudson Carpentry]

I have this one
http://www.axminster.co.uk/axminster-ax ... prod21168/

on metal pipes, very good machine, my only down side isn't that machine but axminsters ali blast gates. I have these and they leak quite a bit. I rang them to which they recommended i put gaffa tape over the leaks (impossible as one big leak is coming from the slot the gate slide out of :roll: Have a guy from axminster coming out next week to have a look at what he can do, when you have 5 gates open the loss of suction is far to great.

 

[Skyhigh_Arb]

Hey Hudson just a thought but have you tried turning them around by 180 degrees so that the suction is against the gate?

May be worth a try for the sake of disconnecting a couple of hoses?

Sorry if that's how they are already fitted just a quick thought. Sorry if I am talking nonsense.

Will

 

[RogerS]

One question I'd ask is how are you going to get rid of the waste and how much do you reckon you'll create? I'd be tempted to keep something like the 2200 on the P/T and table saw and so keep the bag full of largish chippings that you might be able to give away for chickens etc. Then maybe have a smaller system possibly vac based for dustier things.

As far as the SCMS goes, mine is hopeless at dust extraction....and most times I don't bother to connect it up as just as much (if not more) spews out around the machine rather than down the pipe.

HC..if its' any consolation the plastic ones seem to leak as well. Definitely noticed a reduction in suck after I permanently plumbed in my 2200. I agree with you..it's a great machine especially if fitted with a fine filter from RB Industrial or Axminster.

 

[Hudson Carpentry]

Hey Hudson just a thought but have you tried turning them around by 180 degrees so that the suction is against the gate?

May be worth a try for the sake of disconnecting a couple of hoses?

Sorry if that's how they are already fitted just a quick thought. Sorry if I am talking nonsense.

Will

No your correct they do have a correct direction of fit. I have tried this just to make sure it wasn't me fitting them wrong. Its not so much when there closed anyway as its so minimal it barely makes a difference, its when there open.

 

[Hudson Carpentry]

HC..if its' any consolation the plastic ones seem to leak as well. Definitely noticed a reduction in suck after I permanently plumbed in my 2200. I agree with you..it's a great machine especially if fitted with a fine filter from RB Industrial or Axminster.

Yep the plastic ones brake for me, in two normally.

 

[Nick W]

... Jet Air Filter and 5 micro filtration on the 100mm extraction unit and although a good combination I still got a fine layer of dust all around the dust extraction unit.

5 micron filtration is not good enough for fine dust, it just recirculates the stuff - as you have found. To get rid if the harmful fine stuff you really need less than 1 micron.

 

[Hudson Carpentry]

As far as the SCMS goes, mine is hopeless at dust extraction....and most times I don't bother to connect it up as just as much (if not more) spews out around the machine rather than down the pipe.

Mines not to great either, i have mine hooked up to a 75mm pipe system as the reduction from 100mm to 38mm creates a massive drop in suction strength.

I have been looking into blade types to see if there is one that will rake the dust more up to where the suction is.

 

[ondablade]

Hi Dan. As the others and based on the work done by Bill Pentz and on feedback on other forums it seems that if you plan to run the very very fine cartridge type filter needed to catch dangerous dust below 1 micron in size that a cyclone is advisable.

The reason is that the cartridges are quite expensive, and unless your level of usage is tiny they blind up too quickly to be economical or effective if used without a good cyclone that drops out the chips and about 99% of the very fine dust beforehand.

You don't have to do this, and can get by with a much coarser bag filter unit, but as Nick says this will be at the expense of recirculating the fines into the air in your shop which you will then breathe.

The other important variable is the volume of air your system moves - you basically need to shift 800cfm+ to create enough of a depression around the work area on most machines (and need free flowing hoods) to get good dust collection.

There may be the possibility to achieve this using some of the recent canister units with fans giving higher levels of suction with smaller ducting/hose (some of the others here have experience), but the traditional type radial fans used on most bag filter systems needs more motor and 6in ducting/hose to deliver this sort of volume.

If you can use a mobile unit connected to the machine in use when needed using a short 150mm flexible hose it seems a 2hp or so fan with matching impeller will do the business - but you need more HP if you have longer runs of installed ducting. Smaller ducting chokes the flow too much.

This means spending a bit more than the minimum. As ever it's a pays your money and takes your pick sort of deal - it's unfortunately the case that higher levels of dust collection and filtration efficiency cost more than a basic bag filter unit.

The basics are set out here on Bill Pentz's pages http://billpentz.com/woodworking/cyclone/DCBasics.cfm, but it takes a bit of study to get the head around it all....

 

[Tenon]

I am looking at improving my DE too. Like Roger my SCMS is equally messy whether connected or not! I have toyed with idea of creating a hood that accommodates the saw's movement but gather dust better; Tisdai was planning to do this.

An observation of others on the forum, that I agree with is that most machines are lousy at DE at source. My JET air filter is constantly overwhelmed with visible let alone invisible dust particles.

I use the Numatic twin vac from Axi, which with over 3hp is excellent when connected to power tools such as sanders, but it cannot compensate for the poor DE design of my TS or SCMS. It is fine with my Jet P/T but again that has better designed DE.

Knowing what I know now :roll: I would look first at the DE effectiveness of tools beyond their technical capabilities and then at the DE system. I am not relegating the importance of DE systems, clearly you only get one set of lungs etc. but DE can only be as good as the design of the machines it is connected to as I have found out the hard way.

I have also looked at the cyclone systems mentioned by Ondablade which look excellent, but feel I need to improve how I extract dust from my machine sources before I shell out on a cyclone.

Simon

 

[yetloh]

Why would you want to skimp on extraction at the expense of breathing carinogenic dust which could be the biggest long term threat to your business? Buy a cyclone, you won't regret it. I have the Oneida Dust Gorilla - not cheap but worth it.

Jim

 

[RogerS]

I've been thinking a bit more about this. The (heretical?) conclusion that I've come to is that a cyclone is no better than a decent extractor like the 2200.

Seems to me it has to start with DE at the point of cut/sand. Some machines are better than others. Most SCMS's seem very poor in this respect. Digressing slightly, I experimented putting a small hood around my SCMS. Maybe the back of the hood was too close (it probably was) but I found that the velocity of the dust thrown back by the blade simply bounced back at me from the rear face of the hood. The table saw is reasonable unless I have to temporarily remove the crown guard for deep ripping in which case I will use a mask. The planer/thicknesser is average.

The thing is with all the above is not the amount of dust/cuttings that are created but the type. I think we are all agreed that it is the fine dust that does the damage...more specifically the fine dust that we cannot see.

So has anyone done any research into the amount of fine dust that a cyclone extracts out of the airflow? I've played around with a small cyclone and it certainly drops out all the larger stuff and also some dust. But that fine dust? OK...one could argue that the cyclone is dropping it all out because 'my filter is clean' but since we can't see the fine dust then how do you know? More specifically how do you know (unless you use a sub-micron filter on the output of the cyclone) that that fine dust has not been recycled into the air with the rest of the exhaust air from the cyclone?

So if we agree that it is the fine dust that does the damage then the one key item that determines this is how fine a filter we use on whatever extraction system we use and not the extraction system per se.

Just my two-pennorth.

 

[goldeneyedmonkey]

Thanks all,

Yeah I've looked at Bill Pentz's info. But it's a bit overwhelming to say the least.
I want to et a cyclone, but it's going to be 2-3 times the price of a few stand alone DE's + JET air filters.

But I've always had DE as the most important thing to get sorted right first time. It's not like other tools/ machinery as you need to et that stuff eliminated as best as possible before it does any damage to your lungs.

So, what systems do people recommend? Cyclone with ducting. Including decent filters. (I will buy 2x of the JET air filters no-matter what else I buy.)

Thanks for your input _Dan.

 

[Tenon]

Jim

I did not make my point very clearly. I did not mean skimping on extraction. I meant that extraction was important but only after you could make sure that you were extracting it all at source.

If I can see wood dust/fragments lying all over the place after using a tool that is connected to a powerful dust extractor, I can't see the benefit of adding a cyclone, beyond keeping filters cleaner. My Numatic uses HEPA bags as filters so recirculation of fine particles is a less of a concern for me.

I completely agree that I don't want to breathe in carcinogenic material and also sub-micron wood particles are razor sharp and cause lung damage diminishing lung capacity over time.

My tablesaw does not have DE through the crown guard and dumps vast amounts of sawdust inside the saw base and on the floor, despite having a dust port. The saw is a hybrid site/table saw and was a poor choice on my part for using in a confined space.

My SCMS sprays dust everywhere!

The choice for me is to modify my equipment to improve DE, buy again and better this time then I would be in the market for a cyclone if it was better than conventional filtered extraction, always assuming that I had any money left :roll:

Simon

 

[PeterSk]

RogerS is right, a cyclone is not going to take care of small dust, in particular the dangerous stuff.

The point of the cyclone is to create a boundary system between very fast moving air and stagnant air, and then inertia moves the big stuff from the fast moving air into the stagnant air, where gravity takes it away.

However, the fine dust is not going to be affected by the cyclone system, and will stay entrained in the air stream. This is why Dysons have HEPA filters, if the cyclone could remove the fine dust then the filter wouldn't be needed, and they could leave it out increasing the efficiency of the motor and reducing costs as well.

The point of the cyclone is to widen the range of particulate matter your DE system can cope with. If you just have a fine filtering vac system, it'll clog extremely quickly if you use it with a planer for example. However, if you have a cyclone followed by a fine filter system, the cyclone will catch all the big stuff and dump it out of the air stream, leaving just the fine dust for the filters to deal with.

 

[tomatwark]

The Axminster cyclone air flow rates are confusing

I looked into buying one last year.

I also looked at these guys http://www.oneida-air.co.uk/

I decided against going for one partly due to the capacity of the collection drum.

If you are planing up alot of timber you will fill a small single bag or cyclone up very fast and be forever changing bags.

In the end I picked up a big 4hp twin bag unit with enough ducting to do my main machines on Ebay for about £500 second hand.

The cyclone wtih ducting was going to cost well over £2000 and also because of the length of run was probably not going to extract my saw bench fully.

Although still not 100% mostly due to the saw being to old to have crown guard extraction the unit I bought works great, far better than the 3 single bag units it replaced.

Unless you are going to spend £10s of thousands of pounds you will never get it 100%, and all you can do is minimize the risk to your health.

Tom

 

[ondablade]

I can't say for sure Peter regarding efficiency of cyclones on fine dust, but drawing from the intro on the Pentz site he says that a correctly designed cyclone does perform very much better than the dust bin type of separator (which normally develop so much turbulence that they completely scour out at high enough air flows to give decent collection at machines), or the wrongly proportioned cyclones generally sold in the woodworking hobby market.

He argues that the well proven proportions he proposes have long been standard usage in the broader (not just woodworking) fine dust separation industry (much larger and longer than the typical hobby units), and that testing has shown that it does 4 - 5 times better on fine dust and hence on extension of filter life than those normally sold for hobby woodworking.

He claims '99.9% separation on particles down to 5-microns and smaller'. The John Hopkins test of a similarly proportioned but smaller portable Pentz unit on the Clear Vue site (the guys who sell cyclones to his design) while a little heavy on the science jargon seems to show this is fairly well maintained down to below 1 micron. It seems though that there's lots of industry test data out there too.

It's nevertheless clear that cyclone performance does fall away as the dust particles get smaller. So he's clear that the 100% optimum solution is to use a cyclone, but to exhaust outside when weather and the situation permit it to minimise filter cleaning and replacement, and the health risks associated with these. Also to if possible place the cyclone and filters outside to avoid contamination of the work space.

You could of course just exhaust everything outside without a cyclone, but some some sort of chip separation device is needed if you aren't to spew chips everywhere - and it might as well be cyclone shaped.

The essential point he makes on this issue is that in industry where workplaces are subject to regulatory testing against the higher medically driven standards in the case of possibly much more dangerous materials (this is far from being just a woodworking industry issue - pharma and the like have thrown big money at it) these problems have long since been solved - that it's primarily in the case of unregulated and cheapskate woodworking hobby/diy products that the situations remains such a problem.

This lack of regulation or solid information (and the fact that health problems caused by fine dust normally take many years to develop) has in turn led to the development of a majority perception in the hobby (backed by an associated reluctance to spend/accept that maybe 'my' system could be improved) that these cheapie systems must be OK, because 'they' otherwise wouldn't allow them to be sold to us.

The cyclone design he promotes (mostly by making the information available so that people can get over the inherently higher cost of a proper system by going DIY) uses the standard proportions endorsed years ago by the US industry association setting standards in the field of dust separation technology in general.

He's equally clear that the hoods on most machines are just as large a problem, in that they are typically badly designed and suited to the small ducts used on sub standard dust systems. Meaning that most machines need reworking in this area too.

This latter issue is in the end about maintaining airflow/maximising the cfm delivered by a sufficiently large blower. (see the earlier post describing the airflow/cfm (esssentially HP) deficiencies of most hobby market dust systems)

Since air flowing at the sort of low velocities and pressure drops used in dust systems is essentially incompressible even a very short restriction will produce a great drop in cfm/airflow/suction. i.e. it's necessary to make sure the duct cross section is maintained leak free, restriction free and with minimal number bends of the largest possible radius all the way from the machine hood back to the fan and beyond. Surface roughness is a factor too, corrugated flexible ducting creates about x3 the resistance to flow of a smooth duct, and in some cases gets much worse.

Sorry to come across like a zealot on this, but I'm convinced that there's a real need for a very fundamental shift in the way most of perceive the dust collection issue.....

 

[RogerS]

 

[miles_hot]

"s not a good look Roger - don't fancy your changes with the ladies in that get up
Miles