Dust extraction info please

[stevebuk]

hi
my wife want to buy me a dust extraction system for christmas :lol:
The ones i have looked at conect to your tools, but is there a system that sits in the shed just merrily sucking away all the dust from the air, or am i mistaken.
What sort would anyone recomend please.
budget about £250/300

 

[DaveL]

Steve,

I think you are looking for an air filter, like this:

And if you look here you can see the one I made in the shop, mainly from stuff from the scrap pile. :roll:

They are not a replacement for collecting the dust at source on the machine but will remove the fine dust that floats about. It does make a difference in the shop, the filter collects a surprising about of grot.

 

[davy_owen_88]

There are air filters that will remove dust from the air but they are not a substitute for effective dust extraction from the machines. When the dust gets into the air it gets into your lungs, even if after 15 minutes the air is clean again, you were still breathing it in for those 15 minutes, and no-one wants to wear a respirator the entire time they are working...

The Axminster ADE2200 and one or two of these will give you plenty of airflow for extraction from larger machines or a down-draft table for sanding etc.

Of course this will be no good for the small ports on hand held tools where a high pressure extractor is required. There are extractors that claim to do both (camvac etc) but they are no good for effective dust extraction from larger tools as the airflow rates are just not high enough.

 

[Roy Clarke]

You could expect an air cleaner type of unit to take 6 or more hours to clean the air in a workshop, so it really gives a false sense of security IMO.

 

[andys wood shed]

There are extractors that claim to do both (camvac etc) but they are no good for effective dust extraction from larger tools as the airflow rates are just not high enough.

:?
My twin motor, wall mounted, Canvac perform for both small hand tools(one motor) and a 10" thicknesser (two motors) perfectly

You could expect an air cleaner type of unit to take 6 or more hours to clean the air in a workshop, so it really gives a false sense of security IMO.

:?
Air filtration units are sized to circulate the volume of air present in the workshop 6 times per hour.


However it is worth re-iterating the point that it is best practice to remove dust particles at source rather than rely on a shop filter

Andy

 

[andys wood shed]

hi
my wife want to buy me a dust extraction system for christmas :lol:
The ones i have looked at conect to your tools, but is there a system that sits in the shed just merrily sucking away all the dust from the air, or am i mistaken.
What sort would anyone recomend please.
budget about £250/300

Steve,
what type of machinery do you want to connect up to the dust extraction and what type of wood do you intend to cut.

Regards

Andy

 

[davy_owen_88]

There are extractors that claim to do both (camvac etc) but they are no good for effective dust extraction from larger tools as the airflow rates are just not high enough.

:?
My twin motor, wall mounted, Canvac perform for both small hand tools(one motor) and a 10" thicknesser (two motors) perfectly

Sorry, I should have said effective fine dust extraction. Camvacs, even the 3 motor ones do not move enough air to capture the fine dust.

 

[andys wood shed]

There are extractors that claim to do both (camvac etc) but they are no good for effective dust extraction from larger tools as the airflow rates are just not high enough.

:?
My twin motor, wall mounted, Canvac perform for both small hand tools(one motor) and a 10" thicknesser (two motors) perfectly

Sorry, I should have said effective fine dust extraction. Camvacs, even the 3 motor ones do not move enough air to capture the fine dust.

Sorry but we are going to have to agree to disagree on this one :wink:
each motor is rated at;
Airflow: Single Motor 54 l/sec (111cfm)
Vacuum: 2080mm H20

and it filters down to 0.5 microns

Andy

 

[Jake]

Sorry, I should have said effective fine dust extraction. Camvacs, even the 3 motor ones do not move enough air to capture the fine dust.

If that's based on Pentz, you need to account for the fact that his figures are based on 6" throughout all the way to the outlet.

Unless one has gone to the extent of modifying all ones guards and extraction hoods, the figures he presents are irrelevant as you ain't going to get there even with his prescriptions (which are irrelevant at the machine end, because they allow for a massive amount of loss which the high pressure vac will not suffer). In practice the high pressure camvac will shift much much much closer to the same amount of air through a 4" outlet as a 6", than will a low pressure extractor (and even more so if you add in a bunch of 4" pipe or hose as well)- so what might look like a deficit in free air displacement terms soon gets cancelled out.

 

[engineer one]

camvacs do not work as well down the fineness they claim, even the 3 motor type, because to get there, they rely on the filter being mainly blocked which kind of defeats the purpose.

pewntz's figures whilst interesting are in fact neither accurate nor scientifically proven. (refer to the features by our old dearly departed mate barry burgess at the end of 2006.)

you need a double system, something to remove as much dust as possible at the machines, then an after the event air cleaner.

the best form of dust extraction uses a cyclone. because it separates the dust before it gets to the filters.

paul :wink:

 

[davy_owen_88]

Sorry but we are going to have to agree to disagree on this one :wink:
each motor is rated at;
Airflow: Single Motor 54 l/sec (111cfm)
Vacuum: 2080mm H20

and it filters down to 0.5 microns

Andy

It's been done to death enough times on this forum so agreed (to disagree that is :wink:.)

I'll will say just one thing though, I used a record power 'extractor' with similar spec's to yours and it most certainly did not do the job 'perfectly'. Machines with large ports do not need high pressure, they need high volume which is where the camvac/record extractors fail miserably (54 l/sec vs 611l/sec for the ADE2200...)

After using the bandsaw I would get pains in my chest after just a few minutes. Even the next day the fine dust that was still lingering around would cause me to cough my lungs up and at 19 years old the thought of spending my later years with an oxygen tank at my side wasn't too appealing so I did something about it. Since moving to a high volume system I don't have these issues - I don't need to wear a mask because the dust doesn't have the chance to escape from the machine. No matter how many people tell me that a camvac is collecting the finest dust, it will not change the fact that I have seen/breathed the results.

 

[davy_owen_88]

Sorry, I should have said effective fine dust extraction. Camvacs, even the 3 motor ones do not move enough air to capture the fine dust.

If that's based on Pentz, you need to account for the fact that his figures are based on 6" throughout all the way to the outlet.

Unless one has gone to the extent of modifying all ones guards and extraction hoods, the figures he presents are irrelevant as you ain't going to get there even with his prescriptions (which are irrelevant at the machine end, because they allow for a massive amount of loss which the high pressure vac will not suffer). In practice the high pressure camvac will shift much much much closer to the same amount of air through a 4" outlet as a 6", than will a low pressure extractor (and even more so if you add in a bunch of 4" pipe or hose as well)- so what might look like a deficit in free air displacement terms soon gets cancelled out.

It's not based on Pentz, it is based on my own experience. Also you bring up Pentz and his figures, but the 800CFM figure is not based on any anything except the amount of airflow required to capture the fine dust, which he came up with through research and experiments. If you have a low pressure system then you need larger ducting to overcome the resistances to get the 800CFM at the machine, which isn't the case with a high pressure system like a camvac. The argument I am making is that no camvac, or any other high pressure extractor that I have seen can move any where near 800CFM, regardless of hose/duct size. The airflow is what counts, not how big the duct is or how much pressure it can suck at. If the extractor isn't moving enough air to capture the dust then I don't care if I could move that same amount of air using a smaller hose if I were to use a camvac because it isn't doing it's job in the first place.

 

[Jake]

But if you don't have a 6" hood duct, you can forget the rest of Pentz's figures because they are meaningless. Very few people do, therefore you can forget getting 800CFM at the machine with most LP extractors as well. They look good with 1200CFM FAD figures, but at the outlet with typical hobby set-ups the performance is going to be much much much worse.

No, of course they aren't going to match a proper 6" ducted throughout high displacement HVLP set up, but how many (non-professionals) have that anyway?

 

[engineer one]

actually this discussion is going the wrong way.

it is interesting that the latest way for accurate and low loss spraying of paints and varnishes is to us an HVLP device which seems to be more effective than the old fashioned LVHP which was used for years.

what you need is a collection zone, or plenum chamber, and then an HV flow therefrom to the dustbin which you cannot get from the camvac.

paul :wink:

 

[NeilO]

first question steve, How bigs your shed????
its all well and good, these guys telling you zillions of CFM and using 6" piping ( no offence guys , I know where your coming from )but its overkill if you only have a small shed, not that having that kind of filteration wouldnt hurt, but you want to get in there and work too...

I have a 8` x 10` and use RDES2 hooked up to 2 1/2" extraction system (as sold by Axminster or Rutlands)

as well as a Delta/Fox chip collector for my thicknesser and jointer with a Jet AFS 500 ceiling mounted, and it does me...

I believe either Philly or Tony went with the 2 1/2 " system too, and seem pretty pleased with it, its a case of pro`s and con`s I agree bigger has got to be better, but we are talking hobbyist not full scale production..

 

[Jake]

it is interesting that the latest way for accurate and low loss spraying of paints and varnishes is to us an HVLP device which seems to be more effective than the old fashioned LVHP which was used for years.

That is because the HVLP transfers less kinetic energy to the particles, so reducing the wasted spray. It isn't a proper analogy anyway, but if anything, the property an extractor needs is the reverse: to impart as much kinetic energy as possible to the particles.

 

[davy_owen_88]

I don't care about Pentz' figures. Too many people read stuff and repeat it without any experience or knowledge to back it up. I have used a HP system and it didn't work. I now use a suitably sized LP system and it does work. That is all the proof I need.

When I am planning to buy a new machine the first thing I check is the size, location and number of dust ports. If it isn't suitable then I don't buy it. The extractor + filter that I linked to earlier with the shortest length of 4" hose possible will still move well over double the amount of air that a camvac will, and it will do it with about half the noise of a 3 motor camvac too.

 

[Jake]

Ah well, I've used both too, and in my circumstances I prefer the camvac - they are unusual circumstances though, and I wouldn't pretend it is my ultimate set-up. And it is a pain in arse in terms of noise, I'll grant you that.

It certainly works as well as the EB extractor I used to have, and better after 5 minutes of filter clogging use.

 

[engineer one]

all these suggests that the design of the tools is such that enhanced air movement is something that they have.

the fact is that most tools are not designed for effective extraction so we are making assumptions based upon perfect airflow not the reality.

as an example i have closed up much of the underneath of my table saw in an effort to enhance air flow and thus collection. however the dust now seems to get to places it never went before.

my next stage is a proper blade cover but then you have to balance the airflow between the top and the bottom to ensure proper removal of as much as possible.

what any system needs to take advantage of the bernoulli effect and this involves accelerating the air through different size pipes at different points to increase air flow.

paul :wink:

 

[RogerS]

The extractor + filter that I linked to earlier with the shortest length of 4" hose possible will still move well over double the amount of air that a camvac will, and it will do it with about half the noise of a 3 motor camvac too.

Couldn't agree with you more re the Camvac. I bought a twin-motor rebadged (Tyme machine) Camvac hoping it would give me a decent amount of suck. My small Earlex vacuum cleaner from Homebase sucks better.

Davy...I'm assuming that the link you refer to is to the Axminster jobbie?