Dust collection. There is another way

[Oldblock]

Dust collection or in this case dust removal, using a centrifugal fan works very well in certain circumstances. (A warm climate being one of them)
Having observed the very fine layer of dust lying around shops with bag DCs and the hassles of emptying I tried using a cage blower and dumping the fine dust straight through the wall and out of the shop.
I quickly learned that ducting and trapping chips and sawdust wasn’t an option due to the low pressure and after trying out several set-ups I have finished up with a blower out of an old roof mounted evaporative air conditioner installed in the end wall of my shop at floor level. It discharges through the wall into the garden. It blows a veritable gale – the motor is about half horse.

There is no ducting. My machines – saw, jointer, thicknesser, router table, disc and belt sander etc are all located in the vicinity. Fresh air comes in through a door at the other end of my shop.

Fine airborne dust is non existent. Depending on its size, dust and chips from the machines create a trail toward the blower. Jointer shavings likewise grade themselves by size, the small bits disappear completely and heavy chips fall on the floor. I have incorporated a chip collector under my thicknesser that gathers most of the chips that I empty on the garden.

The blower is enclosed in a good-sized cabinet with lots of space to minimise backpressure. Air is drawn in from one side via a kind of bunker that serves as a collection point for heavy particles and any other junk that gets swept up. It also functions as a trap for anything large enough to clog the blades of the blower.

My mitre saw is backed onto this cabinet and the sawdust goes straight though a 150square hole in the front of the cabinet. When I’m cutting mitres I swivel the mitre saw bench a little so that most stuff still heads for the hole. From time to time I clean the whole shop floor with compressed air. Again, fine dust disappears into the blower and the chips and anything else I blow away gathers in the bunker. I have learned where I can use hand power tools so that fine dust goes straight to the blower but sometimes when I’m working on a large work piece I need to hook up my vacuum. I do a limited amount of spraying and the set up works well for this too. I set up my work and just spray toward the blower.

I have a desk and computer in the shop, fortunately the airflow pattern from the shop door to the blower directs clean air past it and only, after several weeks can I can draw a line in fine dust on the desk.

Interestingly there is very little evidence out in the garden of all the stuff that gets blown out.

That's my five cents worth. Reading it over methiks I'm a bit too serious. I'm not a serious guy - seriously.

[journeyman Mick]

Oldblock,
I'd be a little worried about spraying with your setup. If you get the right air/vapour mix and your fan is not spark proof you might have a rather large bang in your workshop.

Mick

[Oldblock]

Your right Mick.

I gave this some thought before my first spray job and it was with some trepidation that I pulled the trigger. There weren't any explosions as is borne out by the fact that I am writing this.

I dont do much spraying and it's usually water based when I do.
Your comment is valued though because familiarity has bred a careless attitude on my part and I will have to look into this before I meet an untimely end and melt all the plastic handles on my chisels.
Anyone got some pointers on spark of flameproof electrics?

Ray

[Cliff Rogers]

G'day.

So long as you don't strike problems with the neighbours...

I had a set up similar to this in a small workshop about 7 years ago. It exhausted into a laneway which was fine as I only used it after hours.
The laneway went between 2 commercial buildings to give access to a car park at the rear. I struck problems when one of the other tenants wanted to park their vehicles in the laneway at night as it was covered & the car park at the rear wasn't. They got a bit P'd off at all the wood dust on their cars.

[journeyman Mick]

Now imagine how P'd off they would've been if you'd been spraying as well and your fan sparked up the lacquer! Hmmm, lacquered barbecued car:D :D

Mick

[davo453]

I notice your in Perth Oldblock, with all that air flowing you must get pretty cold in mid winter.

Mind you I’m tempted to give it a try as I live in a rural area with no close neighbours so who's to know. I'd do this only as a stop gap though until I can do get the cyclone designed, made and running (been saying that for years though).

The risk of fire from a none spark proof motor is a real one, how about reversing the motor/fan and blowing the air out of the door when you spray, not ideal but would have to be better then the way you have it now.

Incidentally neon (specifically the starters) and none enclosed lights are also a real risk in a spray environment, this I know as I am a claims/risk assessor and have seen the results :eek:.

Cheers


Dave

[Oldblock]

Davo yes I supposed it does get a bit nippy in Perth but on a really cold day its not icicle weather and I have a half kilowatt heater shining on my bum anyway. My blower/sucker system is only on when I making dust.
Now before all you safety conscious guys started raving on about electric radiators in spray shop, forget I said anything about spraying it happens in my shop about twice a year and if we are honest about it I bet we all open up a can of something with inflammable solvents with the lights on or a some motor running somewhere.
One has to take notice though when someone like an insurance assessor sounds a cautionary note.
Just as a matter of interest, what kind of concentration of flammable vapours is required for a dangerous condition to arise?
My setup delivers so much fresh air into the shop I don’t even notice a whiff of anything – its long gone.
I’ve just counted the flouros in my shop, there are twentyone and two of them are flickering, the compressor kicks in from time to time (frightens the living bejaysus out of me when I’m deep in thought about flammable vapours), I have oxy/acetylene sitting in one corner, a bottle of propane next to it and countless cans of assorted paints aerosol cans and solvents on the shelves.
Perhaps this explains the distinctly casual behaviour on the part of my wife and I when the national park across the road burst into flames during the warm spell we had a couple of weeks ago and re-ignited itself four times. The heli-tankers kept rattling our best china and we didn’t hear the microwave beep to signal my piece of damp Jarrah was now cooked. Didn’t smell the smoke in the kitchen either. We just sat on the verandah and timed how long it took the choppers to do a round trip and had another chardoney.
But I digress.
Seriously how conscious are we all of the dangers that lurk in or shops and sheds?
I don’t have airborne dust which can be explosive.
I don’t have static electricity problems in vacuum ducts.
I’m not breathing deadly solvent vapours.
I’m not filling my lungs with micron-sized nasties.

Ray

[davo453]

As an assessor I/we see all the horror stories and worse case scenarios, I’m pretty sure we never really hear exactly what happened and have to make assumptions on the cause of a particular claim (or am I becoming a cynic).

I note that you don’t spray often Ray and it is best to keep it to a minimum obviously water based finishes are obviously not really a problem. Spraying is considered to be a serious risk in insurance terms and it does change a businesses risk profile and resultant policy premium (ask your self you would prefer to personaly insure a premises/buisness with spray painting or without and what premium you might charge to do so) ventilation is the key.

Spraying painting by nature creates a large cloud of flammable vapor with lots of air amongst it resulting in a perfect recipe for fire/explosion. Another problem with the application of any flammable product is spillage/over spray on floors, walls and filters, I’ve seen instances were angle grinding or welding was carried out some distance from a spray booth but has flashed off across the floor into the spray booth and caused a total loss of the workshop.

Dust is another potential problem, pretty much all dust is flammable (saw this proven in a science class) the accumulation of wood dust on rafters etc should be regularly removed as a gust of wind or vibration might cause it to be knocked from the rafter over you when welding or operating a naked flame or even over that dodgy neon light starter or circuit breaker. Incidentally switchboards are supposed to be enclosed in a timber workshop environment for similar reasons.

Application of oil is yet another risk in a wood working environment, linseed oil and other oil soaked rags can and often do spontaneously combust (seen the result of that a few times) put them in a bucket of water when you’ve finished with that particular rag.

It’s also good to have separation between your wood store, machinery and flammable goods store. In the event of a fire it would be nice to be able to isolate a source of combustion that way you might actually save something.

I have to admit that I am probably the worst as keeping my shed/workshop clean and tidy and well organised, try as I might I’m just basically a messy person. But it pays to be aware of the risks, looking at my place and the disasters i've seen It's a wonder the place is still standning :confused:.

Don’t even like to think about bush fires, I sat for most of a day a few weeks ago watching a big one in the Chittering area as it tried to make up it’s mind if it would burn through our place or not, fortunately for us the sea breeze came in and it took off to the East away from us, I pity the people down wind though.

Cheers


Dave :D

[dale]

Originally posted by davo453
Incidentally switchboards are supposed to be enclosed in a timber workshop environment for similar reasons.


I've got a switchboard in my shed - a Clipsal 1/2 DIN rail system with the standard plastic enclosure. Is this what you mean, or should it have a secondary cover?

[Oldblock]

Hmmm....

I suppose I could move all the machines out in the garden but this doesn't appeal.

I will look into safer storage for imflamables though.

Had a hose to a dishwasher burst once. It flooded the intermediate floor level, got into the heating ducts, ran down the stairs and flooded my office.

Insurance assessor said it was a common occurance and wouldn't have a dishwasher in his house. I didn't ask him who did the washing up. We have since moved house and the new dishwasher has taps above the worktop which are turned off when washing is finished.

Now I have to address safe electrics, wipe down all the rafters and make another home for my gas bottles.

Gees, I wish I'd never started this thread.

[davo453]

LOL no mate don't you worry, if your in a domestic environment no one will know unless there's a disaster, then well what can you say. I don’t stress about it that’s for sure. Given the limited space in most home workshops things like separation between flammables and timber simply isn't practical.

I deal solely with businesses and most woodworking risk are well aware of the house keeping that's necessary. Those that don’t/wont to comply just look elsewhere for insurance, it is after all their right to do so, at least until the next risk manager comes around.

As long as your circuit breakers are covered, including the switches at the front then you will comply with the standard, which reminds me I must do mine one day :)

Cheers


Dave

[bsrlee]

On the motor subject - TEFC motors seem to be the way to go. (Totally Enclosed Fan Cololed) - there are 4 or 5 grades of the things, everything from dust resistant to bottom of the harbour grades. They can often be found at scrap yards attached to obsolete machinery - just watchout, 415 volts x 40-60 amps is a beast to get an extension cord for, and tends to make the local sub station glow in the dark. Of course they also come in smaller sizes and single phase too ;-)

[PeterJohn]

Hi Guys,
I have followed this thread with interest and find that we are reinventing the wheel regarding dust collection.
The guru regarding dust collection is Bill Pentz and if you are serious about cyclonic collection of dust then his site is well worth a visit. There is a vast amount of information available there. His website is

www.billpentz.com//woodworking/cyclone/index.cfm

Wayne Davey has an excellent site which illustrates his build from Bill's design spread sheet. I hope mine goes as well when I start it as my next project.
Wayne's site is

www.members.optusnet.com.au/waynedavy

Good cycloning

Pete

[Stuart]

:) But we invented the wheel 2 years ago - check the date on the posts. At that stage, Wayne was an active member of this forum, which is where he got into all this cyclone stuff.

[Harry72]

Where is Wayne nowdays?

[PeterJohn]

Thanks Stuart,
I must have been having a Senior moment

Regards
Pete

[IanW]

Where is Wayne nowdays?

Prob'ly pulled the trigger just as the blower sparked and is reading this in orbit... ;)

An interesting thread, despite its great age. I often wonder about contemporary obsessions with safety. Now before you all castigate me for a cavalier attitude, I just want to point out that we all have our phobias and biases. To a cop, most of the people you meet are criminals. I'm a pathologist (vet) so most of my customers are dead. Point being, an insurance assessor sees the things wot went wrong, but doesn't get any idea of how common these events are compared with the actual numbers of oportunities. So we really don't know how likely "possible" events are. (When was the last time you saw someone blown up at the petrol bowser because he/she forgot to turn off the mobile attached to their hip?).
An induction motor, which is the most likely thing making Oldblocks fan go round, doesn't make all that many sparks, unlike a universal motor, hence the statistical chance of it hapening when he is squirting flammable material is probably a little less than winning the biggie Goldlotto. And we all have a concept of how likely that is - especially if you do buy tickets regularly!

Cheers,