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Dust extraction - extracting outside and airfilters

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Jensmith

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I have been reading Bill Pentz's site and it is a bit scary, though I now realise from reading posts on here that he is mostly talking about chip extractors with poor filters rather than a 0.5micron dust extractor. Nevertheless, I would like to act on some of his advice and need a bit of advice from you guys as to how to do it.

I have my triple motor Camvac 386 though I only use 2 motors at a time due to having to run it off an extension cable as the power in the garage isn't designed for power tools.

Anyway, I want to pipe the air from the motor outlets outside to make sure I'm not getting any dust back in the garage and I think I've been told before that it's best to use solid walled pipe to do this so there's less turbulence, but how do you link up 3 pipes into one bigger pipe so you can vent it outside?

I'm guessing you can use something like a vent for a tumbledryer to go through the garage wall? Also, where's the best place to put the vent? If it's near ground level then there's not going to be much air blowing past so it head height or higher best?

Anyone got any pictures of how they did it? If it was 2 pipes I guess you could use a 'Y' connector but with 3 would you link them in with 3 branches off the main 4" pipe?

The other question is related to dust accumulation in the garage. I can see that although I'm using my dust extractor all the time there's a fair build up of dust on all the surfaces and it's getting fairly bad so I want to look at options for combatting this as it is our garage so we have the freezer in there and other stuff stored so it's not ideal that everything is getting dusty.

For this sort of thing will an aircleaner such as a Microclean be worth the investment? I'm thinking as much about my health as I am about my fiances and I don't want dust building up like this.

I'm pretty careful in that I wear a boiler suit and shower cap to stop my hair and clothes getting covered in dust and they stay in the garage but there's bound to be some level of dust being transferred as the garage door isn't exactly dustproof. It's just an internal door off the kitchen.

The other thing Bill Pentz talks about is using a fan to blow air past you, blowing dust away from you and out of a door. Has anyone tried this and does it work? Can you just use a house type fan?

Bill Pentz also talks a lot about airflow being restricted by size of ducting but I gather that a Camvac being LPHV (?) isn't the same, so does airflow still get restricted by reducing the pipe diameter or is this less of a problem with a camvac system?
I ask because nearly everything I have has a tiny port being model makers tools rather than big workshop tools. Apart from my bandsaw they all have 1-1.5" ports!

EDIT: should also add I have a Cyclone central Cyclone as well to separate the dust but it doesn't cope so well with acrylic / plastic dust that I'm often cutting.

Thanks for any advice,

Jennifer,
 

simocco

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I have similar concerns, my work space is very confined and i have no air flow at all. as soon as i start working i seem to stir up dust (if i look towards the light i can see it floating in the air in greater ammounts). i had though of just sticking a great big fan in the open window to see if that would move the hanging dust out side. i remember seeing an old industrial type fan (about 2' in diameter) in a skip i should have given that i go. im interested to see what others think too!
 

beech1948

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Current thinking has moved on a bit since bag style collectors were first created.

Best practice now is to have a cyclone as the best possible solution giving a very hifh collection of even fine dust and exhausting the air back into the workshop so there is little heat loss.

Second best practice ( its pretty close to the cyclonic one) is to use a drop box such as the Thein separator between the DX and the tool. All of the fines are collected in the drop box. I use a Thein separator http://www.cgallery.com/jpthien/cy.htm before my Axminster 2200 fitted with two fine dust filters to replace the bags and I find that the amount of fines making it to the actual DX bag are about 1 cupful per fortnight. I have pretty heavy use of workshop as well.

Third best is the metal can type collector Record/Camvac

Fourth best is probably the bag style collector with a fine dust filter replacing the top bag

Fifth best is the straight forward cotton bag which lets very small dust out all the time to cover the workshop.

If you have many small dust collection ports on tools then use a small workshop vac like a Trend AF30/ Neumatic/ as these are HVHP devices that move a lot of air through small pipes.

The bag style collectors are HVLP style devices that require a minimum of 100mm pipes and collector ports. Bigger machines use bigger DX, small machines use small DX.
Hope this helps

EDIT: Acrylic and plastic are outside my experience entirely. The problems of static electricity causing attraction of plastic bits to other surfaces will be hard to overcome. Maybe you need to ask the plastics industry how they deal with the problem
Al
 

CHJ

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Jen, although a shop air filter will help reduce the settled dust it will as you might gather still only be doing so whilst your lungs are doing the same if you are not wearing a good mask.

You are quite right to be wary of settled dust, if it can be seen then there is too much in the shop air for safety.

In my shop, because heating it is not a major problem I clean up the shop air by venting it outside with a 9" expelair extractor, ensuring that I have a fresh air flow/input (open window) such that it's well away from the extractor outlet and taking the dust away from me.

As far as exhausting your dust collector(s), My extraction system using 100mm piping is just fitted with Y junctions like these, I would have thought similar would work for coupling your exhaust tubes.

Personally I would vent as low as possible to the ground to avoid as much dispersal as possible for the sake of other folks.
 

Jensmith

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I'm not looking at it as a replacement. I always wear my dusk mask and will continue to do so but we still go in and out of there and so reducing the level of general dust seems like a good idea too as long as it's not going to make things worse.

I think using perhaps one of the bench top models might be good to suck air away from me and filter it used close to the machine that's generating the dust?

I do have a problem with air in the garage as the windows don't open - it's just glass. I assume for security. The garage also has only 2 exterior walls, the other two being the hall way and the kitchen so I'm not going to be able to get a through flow of air like you either. Because of this the only opening is the garage double doors which isn't ideal as it would be freezing in winter and also it means noise is going to be more noticeable outside for neighbours etc so I'm not sure what to do really.
 

beech1948

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All this chat about "air flow" through the windows and Expelair fans is just that ........chat. Neither option is a realistic solution. You would be kidding yourself if you went down this route.

The Bill Pentz site is very clear that wood dust is toxic and harmful...why take any risk with half assed methods. Wood dust needs to be removed at source, as completely as can be managed. That takes a little thought, a little money and a lot of activity.

OR go back to only handwork, hand tools and do not use MDF.

What sort of face mask are you wearing and is conformant to a P3 type.

Al
 

siggy_7

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beech1948":3pxh4t8j said:
All this chat about "air flow" through the windows and Expelair fans is just that ........chat. Neither option is a realistic solution. You would be kidding yourself if you went down this route.
I don't think anyone is suggesting this as one's only protection against dust, but in combination with an extraction system (which is rarely going to capture every last speck, even to Mr Pentz's ultra high capacity way of thinking) and respiration protection, increasing the air changes/hour significantly must reduce airborne dust in the workshop. Although only a viable solution when the workshop doesn't need heating, as you need to shift a lot of air!

Regarding Jensmith's original question about how airflow is affected by pipe diameter, yes reducing the diameter will still reduce airflow - with a smaller diameter, the velocity through the pipe will increase, and so will the pressure losses, but the loss in area through the pipe (volumetric flow is product of mean velocity and area) will have the greater effect over the velocity increase, and flow rates will reduce. However, unlike LPHV systems, HPLV systems are better able to generate the increased pressure drop required to drive a fast flow through a narrow pipe, so the pressure drop increases as you reduce the area (notice how a vacuum sucks much harder as you partially cover a hose). So you will still lose airflow, but not as bad as with a LPHV system, which will stall aerodynamically.
 

Jensmith

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Al - I'm using a 3M 7500 half mask with 2135 P3 particulate filters.

I've tried asking the professionals about extracting what I'm cutting but they use industrial extractors and it's neither affordable or practical to go down that route.

I mostly use my bandsaw and we all know how hard it is to extract effectively from a bandsaw.
I have under the table extraction and a port above the table which helps but with static it's a nightmare.

I have got a different bandsaw now that I'm just getting set up and i am going to modify my under the table port to be more like Bill Pentz's suggestion which also means I will make the port 4" rather than my current design which is a short connection of just 2.5". It does collect debris at the transition so I know it's reducing the flow.
 

wallace

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I tried some experiments when I had my lathe in my main workshop. I think it is impossible to collect the dust produced at source with a lathe. I mounted a big extractor fan (a big fan from a car scrapyard) into a window and then had my lathe infront and a desk fan mounted from the ceiling in the direction of the lathe. It was really succesfull at drawing the dust out when I was power sanding and stopped the whole workshop from getting blanketed in dust. I would also leave it running on a timer to clear the whole workshop. I did this in conjunction with my 3M dustmaster.
Mark
 

simocco

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wallace":2ljmy6rh said:
....I mounted a big extractor fan (a big fan from a car scrapyard) into a window ....
Mark
Nice, i had wondered if this would be effective....what kinda size of unit was it? did it run off the mains etc..any pic's

cheers
 

CHJ

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Basically that is how my 9" commercial expelair is arranged, immediately behind the lathe, the airflow passes me and entraps the majority of the dust cloud that escapes the high volume extractor positioned near the chuck and dumps it outside. It is also wired on a thermostat as a cooling aid for the shop as any bright sunny day sees my shop in the 20's.
As to comments about not being effective, every couple of weeks I need to go out and brush the dust debris and cobwebs off the rain hood to make it look more respectable and the settled dust in the shop reduced a factor of ten at least after I started exchanging the air.

I keep a polished piece of stainless on a shelf as a guide to how much is about, wiping a finger over it soon shows what is settling.

My only guide line is that I have no more settled dust in the shed when working the lathe than when I have not been working in there for a week and airborne dust is just down to the parrot that that shares a section of the shed as a flight.
 

wallace

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Heres a couple of pics of my fan, its a 12" one I think I took it off a little micra at the scrapyard. I have it wired to a battery charger. I found it was a cheap solution for the problem





Mark
 

beech1948

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Jensmith said:
Al - I'm using a 3M 7500 half mask with 2135 P3 particulate filters.

I've tried asking the professionals about extracting what I'm cutting but they use industrial extractors and it's neither affordable or practical to go down that route.

Jensmith,

OK...your doing what you can and the P3 mask will help a lot. I guess I came off as a bit severe in my comments but loose dust was a nightmare for me and its taken some effort to clear most of it up at source.

I think you have a bag style collector. Have a look at the Phil Thein web site and then consider building one...it is almost as good as a cyclone and cheap to do. Many have included the Thein baffle into the body of the bag style extractor.

Your bandsaw will always be a problem but with some application you can seal one up fairly well. For your plastic bits I think yop are just having to go for moving as much air as possible to grab as much plastic dust as you can. Maybe even earthing the table and or the upper body to keep static at bay. On a bandsaw getting the lower guides and blade sealed up with the 4" extraction point as close as possible will pay off subject to the plastic being affected by static. It took me three months of trial and error to get my Startrite 352 sealed up and extracting OK but not spectacularly well.

It can be done and quite cheaply but as I said it takes effort and a lot of reading/thinking.
Al
 

Jensmith

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beech1948":12bdkr98 said:
I think you have a bag style collector. Have a look at the Phil Thein web site and then consider building one...it is almost as good as a cyclone and cheap to do. Many have included the Thein baffle into the body of the bag style extractor.
No, it's not a bag extractor. A Camvac is a vacuum extractor with triple stage filtering down to 0.5 micron but with the plastic dust it gets clogged up quickly and I can see that bigger particles are getting through the filters.

I have a proper cyclone which does do a great job of separating out the bigger dust but the plastic dust is kind of like talcum powder and seems to slip through.

My current bandsaw isn't sealed - it's an old bandsaw I got 2nd hand and I've done my best but it leaks dust like a sieve and throws it everywhere.

I have just got anew 2nd hand Startrite - a 3 wheeled one - and I'm hoping this will be better as at least the cabinets are sealed!
 

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