Thread: Room cleaner air filters - are they any good?

My understanding is they look good and use Electricity, I am open to be corrected.

My (very unscientific) theory is that if there's dust on the filters that's dust that isn't in your lungs or coating the surfaces of your workshop. ⅛ HP should cost about 3c an hour to run.

A rule of thumb I was taught was that it needs to handle the whole room volume every 1 to 3 minutes.

Not that I can cite any dox to back that claim up, but still...

Anyways, at only 400cfm (assuming that's an honest figure) that means it'd do around a 7'x6'x10' room every minute or a 7'x10'x18' every 3 mins.

Probably alright for a small one car garage.

Originally Posted by jack620

My (very unscientific) theory is that if there's dust on the filters that's dust that isn't in your lungs or coating the surfaces of your workshop. ⅛ HP should cost about 3c an hour to run.

Yes. I have one. Haven't used it in my new large shed yet, but in my old double garage shed I could definitely tell when I hadn't turned it on. I would also set the timer to run for 3 hours after I left the shed.

I was very regularly cleaning both of its filters, so it definitely caught dust. My dust collection at the source was poor, something I am fixing in my new shed.

It also gave the slightest of breezes on the other side of the garage, which was a bonus.

I might need 3 (definitely 2) in the new 140sqm shed with 5.5m roof height, I wouldn't hesitate too much if I wanted to put them in my new shed.

The overall effectiveness of a RAF (Room air filter) Depends on things like.
- RAF performance specs
- Size and Shape of the shed
- Location within the shed
- Amount (and where dust is generated in the shed) of sawdust generated per unit time
- What other dust collection setup you have available.

eg 1
long "L" shaped shed with RAF located at one end of "L", lots of sanding with a large belt sander and no other dust collection venting outside shed - chances of an RAF being effective is very poor.

eg 2
Small sized square shed with RAF located in middle of shed, mainly using hand tools - chances of an RAF helping is very good.

eg 3
Medium sized square shed with RAF located in middle of shed, mainly using machines with effective ducted dust extraction collecting at source and venting outside - chances of an RAF helping is very good.

Bigger/dustier sheds need more RAFs but they will not replace the use of a good DC system as they have little chance of keeping up with the volume of dust generate by poorly extracting machinery. RAFs will assist with cleaning up a shed quicker after machinery has stopped making dust.

RAFs are really designed for collecting residual dust that all machines generate but even top shelf DC systems leave behind. This helps with subsequent activities such as applying finishers . A decent DC system that vents outside will drag outside air and dust inside a shed so provided no further dust load is added to the shed running a RAF will help remove the dust that came into the shed along with the outside air.

I have a long L shaped shed with a true 800 CFM hospital grade RAF mounted near the middle of the "L". My DC system is a 4HP variable speed unit located that vents outside the shed but I never use the RAF while running machinery - that's a sure fire way of clogging a very expensive filter. After I stop running machines, running the RAF for ~30 seconds or so my particle counters shows the air coming out of the RAF had ZERO particles of >0.3 microns. Depending on how much residual dust was generated and other dust has been dragged in from the outside it takes around 10 minutes to clean the air up in the immediate vicinity of the RAF so I can use it for applying finishes. I rarely use the RAF these days which shows how often I'm applying finishes

To simply scrub the air of residual dust left behind by machines I tend to just run the DC for a few minutes after making dust which gets he dust levels in the shed down to what is already in outside air.

Originally Posted by BobL

The overall effectiveness of a RAF (Room air filter) Depends on things like.
- RAF performance specs
- Size and Shape of the shed
- Location within the shed
- Amount (and where dust is generated in the shed) of sawdust generated per unit time
- What other dust collection setup you have available.

eg 1
long "L" shaped shed with RAF located at one end of "L", lots of sanding with a large belt sander and no other dust collection venting outside shed - chances of an RAF being effective is very poor.

eg 2
Small sized square shed with RAF located in middle of shed, mainly using hand tools - chances of an RAF helping is very good.

eg 3
Medium sized square shed with RAF located in middle of shed, mainly using machines with effective ducted dust extraction collecting at source and venting outside - chances of an RAF helping is very good.

Bigger/dustier sheds need more RAFs but they will not replace the use of a good DC system as they have little chance of keeping up with the volume of dust generate by poorly extracting machinery. RAFs will assist with cleaning up a shed quicker after machinery has stopped making dust.

RAFs are really designed for collecting residual dust that all machines generate but even top shelf DC systems leave behind. This helps with subsequent activities such as applying finishers . A decent DC system that vents outside will drag outside air and dust inside a shed so provided no further dust load is added to the shed running a RAF will help remove the dust that came into the shed along with the outside air.

I have a long L shaped shed with a true 800 CFM hospital grade RAF mounted near the middle of the "L". My DC system is a 4HP variable speed unit located that vents outside the shed but I never use the RAF while running machinery - that's a sure fire way of clogging a very expensive filter. After I stop running machines, running the RAF for ~30 seconds or so my particle counters shows the air coming out of the RAF had ZERO particles of >0.3 microns. Depending on how much residual dust was generated and other dust has been dragged in from the outside it takes around 10 minutes to clean the air up in the immediate vicinity of the RAF so I can use it for applying finishes. I rarely use the RAF these days which shows how often I'm applying finishes

To simply scrub the air of residual dust left behind by machines I tend to just run the DC for a few minutes after making dust which gets he dust levels in the shed down to what is already in outside air.

Thank BobL! I will be in the middle between eg2 and eg3 at the momen.
It's a small squared garage and I intend to buy a 2hp unit soon (I know it won't be enough but that's what I can afford both economically and from a footprint point of view).

Speking of which, I wanted to ask you a question.
Can this unit (DC-1500T 2hp DUST EXTRACTOR 1300cfm | Leda Machinery) be considered a good alternative to your modifications to the outlet? It looks like the square duct that connect the motor to the filter bag attachment serves the same purpose...am I wrong?

Originally Posted by Jekkil

Thank BobL! I will be in the middle between eg2 and eg3 at the momen.
It's a small squared garage and I intend to buy a 2hp unit soon (I know it won't be enough but that's what I can afford both economically and from a footprint point of view).

2HP might be OK for a small shed - how small is it?

Speking of which, I wanted to ask you a question.
Can this unit (DC-1500T 2hp DUST EXTRACTOR 1300cfm | Leda Machinery) be considered a good alternative to your modifications to the outlet? It looks like the square duct that connect the motor to the filter bag attachment serves the same purpose...am I wrong?

The downside of using that design without modification is that the air path has to do a 90º corkscrew when in enters the bag housing which will slightly reduce flow and the separation effect of the bag housing. The effect is likely to be small but given these 2HP units are borderline it's handy to grab every small bit of benefit possible. I usually recommend people look for used 2HP TC or CT extractors which come up fairly often..

Originally Posted by BobL

how small is it?

It's a one car garage, 4 meters by 6 meters probably 3 meters high.

Originally Posted by BobL

The downside of using that design without modification is that the air path has to do a 90º corkscrew when in enters the bag housing which will slightly reduce flow and the separation effect of the bag housing. The effect is likely to be small but given these 2HP units are borderline it's handy to grab every small bit of benefit possible. I usually recommend people look for used 2HP TC or CT extractors which come up fairly often..

Understood, I'm looking for a used one as a matter of facts....what does TC or CT mean though?

Originally Posted by Jekkil

It's a one car garage, 4 meters by 6 meters probably 3 meters high.

Thanks - should be OK

Understood, I'm looking for a used one as a matter of facts....what does TC or CT mean though?

TimbeCon and CarbaTech

Another bit of info from me. When my room cleaner was in the double garage sized shed, I had it mounted in one side, about 2/3 back. I pointed the rear exhaust vent towards the other side of the garage. That created a bit of recirculation around the shed in a circular motion which may have helped.

Originally Posted by BobL

TimbeCon and CarbaTech

Thanks Bob, clear now


Further question...would you buy a dust collector that is almost 30 years old?
A guy close to me has 4 of them and he's selling them for $100 bucks.
I'm going to have a look at them...anything I should be aware of?


Thanks!!

If you can still buy filters for it, why not? It’s just a blower in a box.

Originally Posted by Jekkil

Thanks Bob, clear now


Further question...would you buy a dust collector that is almost 30 years old?
A guy close to me has 4 of them and he's selling them for $100 bucks.
I'm going to have a look at them...anything I should be aware of?

30 year old ones are most likely to have cloth bags for both collection and air filtration that when new are only good to about 30 microns, but worst of all likely to have a heap of micro holes all over them. Unless you can vent outside the shed and don't have any close neighbours I'd only get one if you can get replacement filters and plastic collection bags for it. Take some photos of the old DCs and post them here for more advice.

OK, maybe I’m confused. Are we talking about dust extractors or room air filters (the subject of this thread)?