dust extraction

[Mreco99]

HI

Do you know what size dust we are creating with our scroll saws? I need to think about some sort of dust extraction system. Some are listed as class L or class M, some state dust to 1 micron or 0.5 microns (some only say dust to 30 microns). Also some are 1200w some are 500w. Never having ever had dust extraction, i don't want to buy the wrong thing.

And also, what do you do for dust extraction. I don't want to damage the lungs.

Thanks

 

[Inspector]

Somewhere in Bill's site, http://billpentz.com/woodworking/cyclon ... #index.cfm he said sawing a 7" / 180mm through a 1" / 25mm board with a handsaw produces enough fine dust to contaminate a workshop. That dust being invisible to the unaided eye is among the dust you can see which is about 20 microns and larger. You want 0.5 microns. That dust you can't see behaves like a gas and it rises up past your nose to float around for hours. Think of food smells lingering in the house long after cooking. Ordinarily I would tell someone wanting to collect dust from the usual woodworking machines to get a 2hp DC as a minimum with cartridge filter and use 6" ducting. Your scroll saw doesn't throw the dust like a table saw so it is easier to capture. You could use a 1hp unit and a 4" duct to the scroll saw. The duct being placed above and a little behind the blade with a bell mouth hood. Better would be a bigger DC with a 6" duct, split to a pair of 4" ducts, one above and the other below the table much like you would for a bandsaw. If you have plans to get more woodworking machines like a drum thickness sander then get the bigger DC to begin with. I wouldn't use a vacuum cleaner type machine because it doesn't capture air/dust from very far away from the end of the hose. The bigger the hose diameter the farther away it can capture the dust.

 

[Mreco99]

Thanks Inspector for your detailed reply.

I'm in the UK, 2hp 1hp, is that horse power?
Do you have a link to something?
Also i am a home user, not a commercial workshop, so its really for this one device.

I don't know if this is classed as a 'vaccum' type
https://www.screwfix.com/p/scheppach-ha ... 240v/15408

I think you might mean this is a vacuums type to avoid?
https://www.screwfix.com/p/scheppach-hd ... 230v/31896

This one says 1.175 Microns, ive no idea if this is any good? its not 0.5microns so probably not fine enough.
https://www.screwfix.com/p/scheppach-ha ... 230v/65112

You see my confusion?

 

[Inspector]

Yes the "hp" being horse power. Watts is rarely used here to sell motors et cetera.

Your first link is what I would term as a vacuum cleaner as it is a high pressure low volume machine (HPLV) as is the second. In our 110 volt world the first ones don't exist because we don't have the power to run them. The second with hoses up to 2.5"/65mm are all we have and that's why I didn't recommend it. The first with it's 4" hose could probably do the job.

The last one you linked with the bag filter is a low pressure high volume (LPHV) machine but the bag filters are difficult to keep clamped without leaking from folds etc. and the media is not fine enough. They are better with a cartridge on top if it is a quality unit. More along the lines of this one. https://www.screwfix.com/p/scheppach-wo ... _container I link it because it is from the same place and there are likely equal or better ones from other companies.

Keep in mind that most all the LPHV machine airflow claims are exaggerated buy as much as double what they actually can do. That is because they test without filters and only a short inlet duct, testing in the centre of the duct. That gives them the highest reading for marketing. In the real world with filters, ducting/hose you won't get those flows.

Something else to know is that a 4"/100mm duct can at most move 450 cfm/760 CM (cubic feet per minute/cubic meters per hour) and the hoses restrict more. A 6"/150mm duct can move 1000cfm/1700 CM. It is all on that link I referred to in my first response. A lengthy read but worth it. He does seem to repeat himself a lot but that is because many will cherry pick a few parts and he wants to get the point across.

You'll see many extol the virtue of room air cleaners but they are getting the dust while you are breathing it so it is much better to catch it where it is made. Ventilation when the weather is good is better so is having the DC separate from the shop of venting outside.

It is easy to buy a woodworking machine as the specifications are obvious, but dust collection has many variables that make it hard to choose and implement. In most cases bigger is better but comes at a cost that makes people cringe. You have to decide what you can afford and how much you would like to risk your health.

Pete

 

[loftyhermes]

I wear a mask (sometimes) and connect a Henry cleaner to my scroll saw.

 

[Mreco99]

Thanks for fabulous replies, really appreciate the effort.

Whilst i know you cant put a price on your health, i cant drop £500 on a dust extractor. I need a cheaper solution.

I also considered a mask, take a look at this one. What do you think? Could you have this instead?
https://www.axminster.co.uk/axminster-a ... tor-101809
UPDATE: I read the mask isn't sufficient on its own.

I totally agree with capturing the dust as its made, what do you think of this one? I know its a vac, but the specs are good?
https://www.screwfix.com/p/festool-ctl- ... 240v/5315x

 

[Inspector]

As much as the specs are good as far as filtration the Festool still won't have the oomph to pull the dust from any distance from the blade of the scroll saw letting lots escape. You can see how far by taking your house vac and putting the hose to the edge of a sheet of plywood. Take some flour and sift it over the plywood and see how far away it is pulling the dust by what lands and stays on the plywood. My shop vac with a 2 1/4"/55mm hose will only pull from about 2"away. With your scroll saw would you be happy having the nozzle in inch or so from the blade? And it would still need a second under the table. Here a quick video of a bigger duct with a bell mouth hood pulling from a lathe spindle. https://www.youtube.com/watch?v=xjtHCmR-N3M That is a 6" opening and it easily coping with the sanding dust several inches to the opening and a lathe is much harder to capture from. A 4" duct with bell mouth would pull the dust much better than the 1 1/4" to 2 1/4" of a vacuum cleaner. So if you can't afford the bigger machine at least get the vacuum with the 4" hose like the first link you provided. Maybe two so you can get the dust from below the table too.

If you are only going with a powered respirator or a cartridge half or full face mask remember the dust will be hanging in the air for hours after you finish sawing and sanding. So you need to wear the mask all the time you're in the shop and if the shop is in your house that dust can find it's way through it by way of door openings and heating ducts plus what is on your clothing.

Pete

 

[Mreco99]

Thanks for sharing your knowledge. Thats a BIG sucker!!
OK so I'm going to try and find something with a bigger hose, and a class M extractor
(i don't know if the 'class' system is universal, class L, M, H)

Is this one unless for me (Scroll saw hard wood) as its 5 microns?
https://www.machinemart.co.uk/p/cde7b-dust-extractor/

Another one for your thoughts, 0.5 microns, large hose, probably a bit noisy, but what do you think?
https://www.machinemart.co.uk/p/record- ... tion-dust/

 

[Inspector]

The "BIG sucker" is a 3hp DC in Australia and he has it set up outside in an attached shed so the dust doesn't come back inside. Warm climate. :roll: My climate is colder and mine will have to be inside with lots of cartridges. It's a 5hp cyclone.

You could get the first one in your last post and replace the filter bag with a cartridge from these people. http://www.djnuk.co.uk Then you'll have enough airflow for your scroll saw and the .5 micron filtration. It wouldn't cost much more than the vacuum in the second link. You will have to adapt it some to fit. A forum member did the same in the last year or two but I can't find it at the moment.

Dust collection is noisy but since most wear ear protection, the saws and planers are louder, it isn't so much of a problem. The LPHV machine above won't be too bad and may bother you. Enclosing them in a soundproof closet with a baffled air return reduces the noise a lot but you have to sacrifice some space.

Pete

 

[Mreco99]

Thanks inspector,
The noise thing isn't a problem for me, as im in a garage, its me being considerate to my neighbours. Would be very interested in the soundproof closet, i can give that a bit of space. I can make something, but im trying to find out how much air it actually needs, don't want to blow it up lol.

 

[Inspector]

The air duct out of the closet should be at least 2 times, preferably 3 times the size going in. So 4" in = 12.57 square inches so 25 (161cm) or better 40 ish (258cm) square inches out. Have that run as a box down the side of the closet (mineral wool insulated) with baffles to make a bit of a zig zag maze lined with mineral wool, sound absorbing foam or acoustic ceiling tiles and you'll be able to hear someone else's thoughts. An alternative to the baffle box is the soft lined air-conditioning ducting (10" or so diameter) with a few bends in it. Tie it to the ceiling.

Pete

 

[Inspector]

This is the thread I referred to earlier where the bag filter was replaced by the cartridge. post1247579.html?hilit=filter#p1247579

Pete

PS. Forgot to mention the cloth bags make reasonable sacks. :wink:

 

[Mreco99]

great info thanks Pete. Ive got things to work on now

 

[Inspector]

You're welcome. Hope it goes without saying you can get a used bagger, hopefully bigger, for cheap and put the cartridge on it too.

Pete