Thread: Dust extraction for a small shop

The 2HP DC (especially after it has been modified according to the sticky on this forum) will by far be a better device as it has the largest air flow.
BUT
None of them will be much chop unless you can at least vent them outside - all you will end up doing is recalculating finer and finer dust in the shed.
Remember its not the chips that are a health concern but the invisible dust.

Can you at least put the DC in an airtight enclosure on a wall or even in the ceiling and vent the enclosure outside?

Even if you can hang a duct out the window it will be better than nothing.

Hey Bob,

Is it ok to put into an airtight enclosure?

I could then run a vent under the garage door

Originally Posted by BobL

The 2HP DC (especially after it has been modified according to the sticky on this forum) will by far be a better device as it has the largest air flow.
BUT
None of them will be much chop unless you can at least vent them outside - all you will end up doing is recalculating finer and finer dust in the shed.
Remember its not the chips that are a health concern but the invisible dust.

Can you at least put the DC in an airtight enclosure on a wall or even in the ceiling and vent the enclosure outside?

Even if you can hang a duct out the window it will be better than nothing.

Sorry Bob,

What part should vent outside?

Sorry if this is a stupid question.

Darren.

Originally Posted by BobL

The 2HP DC (especially after it has been modified according to the sticky on this forum) will by far be a better device as it has the largest air flow.
BUT
None of them will be much chop unless you can at least vent them outside - all you will end up doing is recalculating finer and finer dust in the shed.
Remember its not the chips that are a health concern but the invisible dust.

Can you at least put the DC in an airtight enclosure on a wall or even in the ceiling and vent the enclosure outside?

Even if you can hang a duct out the window it will be better than nothing.

Originally Posted by Dazm

Hey Bob,

Is it ok to put into an airtight enclosure?

Yep, provided ut really is airtight it's as good as it being outside.

I could then run a vent under the garage door

The vent should be 2 to 4 times the cross sectional area of the air intakes or it will add significantly to the back pressure and reduce the flow.
So as long as you cab get that under the door - any chance of putting a hole in the door itself?

No can't put a hole in the door (

Would separate shop vacs for each machine not do a better job? Won't I lose a lot of suction running piping to each machine from the one DE?

Originally Posted by BobL

Yep, provided ut really is airtight it's as good as it being outside.



The vent should be 2 to 4 times the cross sectional area of the air intakes or it will add significantly to the back pressure and reduce the flow.
So as long as you cab get that under the door - any chance of putting a hole in the door itself?

Shop vacs are hopeless on machines.
Like a DC, shop vacs should also be located or vented outside

I've been using my shop vac with a filter bag and thien baffle and it's not horrible. 20 feet of 2-1/2" hose and I connect to whatever I'm using at the moment. I've only got a bandsaw, radial arm, miter, router table and some sanders at the moment, so when I get a planer I'll probably have to upgrade.

Sent from my SM-G900V using Tapatalk

I just have no way to locate the 2hp unit outside nor vent it outside. Surely a dedicated shopvac with a dust deputy for each machine will do a better job than the 2hp dc inside the workshop? The top bag on the dc is covered in dust so surely this will return far more dust to the air?

The dust deputy is great. The clear vue one is even better but neither well be as good as a DC on machines. It is all about the diameter of the suction hose. If you can't put your DC outside, you should consider getting the upgraded filter to replace the filter bag that came with your DC. That well drastically reduce the fine dust that escapes.

Originally Posted by Dazm

I just have no way to locate the 2hp unit outside nor vent it outside. Surely a dedicated shopvac with a dust deputy for each machine will do a better job than the 2hp dc inside the workshop? The top bag on the dc is covered in dust so surely this will return far more dust to the air?

When used inside a shed, both shop vacs and DCs are, to put things in plain speak, near useless at controlling fine dust.

Shop vacs are great for picking up chips from power tools but struggle on a number of fronts
- they operate with air flows about 10 times too small to grab enough fine dust in the first place
- the motor cooling loops generate large amounts of fine dust from the relatively few larger particles that pass through the motor column loop
- On cheaper shop vacs most fine dust goes straight through the filters and back into the shed
- they eventually leak

A stock 2HP DC is better than a shop vac at picking up chips from machine but struggle on a number of fronts
- they operate with air flows about 2.5 times too small to grab enough fine dust in the first place
- some fine dust goes straight through the filters and back into the shed
- they also leak.

The fine dust seen on the white DC collection bags comes from a variety of sources
- dust that was never even collected in the first place - put a white sheet down anywhere in a shed and you will see this.
- dust that came from leaks in the DC and fogged the air around the dust collector
- dust that came through the filter. If the filters are calico or thin needle felt they will let more fine dust through

All this is why DCs and VCs should be vented outside a shed.

Pleated filters (PF) are mot that much better at filtering fine dust than the thicker needle felt (NF) filters.
PFs do allow more air flow and take longer to clog than NF filters

Dazm,

Not sure if I'm tell you how to suck eggs, but here goes.....

1. Wood Chip collection from the devices is one aspect of what you're trying to achieve. Keep the garage clean of wood chips from the thicknesser and joiner, etc. But that's the easy bit of the job.
2. The most important part of the job is dust extraction. There's heaps been written about the subject on this forum, and elsewhere, but basically, the very fine dust that is created by your woodworking machines (the dust that is too small to see) has been proven to be dangerous to your health, and to the health of your family, if your garage opens directly into your house. You need to use an appropriately set-up dust extractor to collect that dust at source and exhaust it outside. Just how dangerous that very find wood dust is is constantly being debated amongst the medical world, but what is confirmed is that the very fine dust can over time cause allergies, emphysema, asthma and other lung diseases. Some medical professionals also believe that the very fine wood dust causes cancer of the nose, throat and lungs, but as I understand it, the evidence is not yet proven conclusively. Don't be scared off woodworking because of those risks, because it is relatively easy to mitigate against those health risks.
3. Some woodworkers on this forum are only concerned with having effective wood chip collection. If asked, they will tell you that they aren't concerned with any health issues with breathing fine wood dust - they will tell you that "they've been woodworking and breathing the dust for 20 or 30 years and there's nothing wrong with them." That's their opinion, and they're entitled to express that opinion.
4. Other's if asked, will tell you that they are aware of the risk of breathing fine wood dust, but that the cost of dealing effectively with the fine dust is too high and the task too difficult in small workshops, so they do the best they can with what they can afford, in the space available. I used to be of that opinion, until I started to get asthma (when I'd never had it before) and the Doctor proved last month that the asthma was caused by a wood dust allergy. These days, I'm always looking for innovative ways to improve the dust collection in my workshop, without having to spend lots of money.
5. There are also other woodworkers on this forum who can attest to the fact that breathing fine wood dust causes allergic reactions, or gives them asthma, or aggravates their existing asthma, or causes throat soreness or inflammation, and other heath issues. I know of one retired bank manager who has been a hobby woodworker for the last twenty years, and who has never smoked in his life, but now has emphysema (which is normally only a smoker's disease). Biopsies of his lungs have identified wood dust deep in his lungs as being the most likely cause of the emphysema.
6. If you do the dust collection job well enough to minimise the health risks from breathing very fine wood dust, then the wood chip collection will take care of itself.

Enough of the lecture - sorry for the rant.

The Carbatec 2 HP Dust Extractor is normally on castors. Can you put the dust extractor on the end of a length of 100 mm (preferably larger, 125 or 150 mm as per BobL's sticky on modifying the generic 2HP Dusty) flexible dust collector hose, and simply wheel the dust extractor out onto the driveway when in use. If any breeze is going to blow the exhaust from the dust collector back into the garage, just close the roller door down onto the dust collector hose. When you get the time, modify your 2 HP dust Extractor to get the greatest volume air flow possible out of it.

The above suggestion is not an ideal solution, but it does make sure that the exhaust air from the dust collector filter is outside of your garage, so you'll not be breathing in the very fine and dangerous dust that escapes through the dust collector's filter.

Unfortunately, your neighbours may object to the dust collector's noise. Do a noise test. You'll need to fit the dust extraction hose, and connect it to one of your machines, to get a true indication of the extractor's noise levels. Once set-up, leave the dust extractor running on the driveway, and go for a walk along the street, say up to one allotment either side of your house, and see what the dust extractor noise sounds like. From my experience, once you get outside the neighbour's yard, the neighbour's pool pump or external air conditioner unit is most likely noisier than your dust collector.

If your Carbatec Dust Collector still has the Felt Filter Bag fitted to it, you can replace the felt filter bag with a pleated filter Canister which reduces the noise level of the dust extractor to some degree, as well as providing much better, but still not good enough, fine dust filtering. Also, be a good neighbour, and only use your machinery and dust collector during reasonable hours, and all should be well. If you're in a high density housing area, then you might need to modify the above slightly by placing the dust extractor inside a mobile cupboard that can be configured as a "muffler" for the dust extractor noise.

As far as cyclones go, from my experience with them , all they do is to separate out the heavier particles into the cyclone bucket which may be easier to empty than the dust extractor bucket. The cyclones do not separate out the fine dust particles that cause the health issues.

I hope that info helps. Suburban woodworking is a growing trend, and as many people do machine woodworking, rather than hand tool woodworking, the issues that you are encountering with noise management and dust management are going to become more and more common, especially as city dwellers move to higher density housing estates.

I hope that information helps.

Regards,

RoyG

Originally Posted by RoyG

If your Carbatec Dust Collector still has the Felt Filter Bag fitted to it, you can replace the felt filter bag with a pleated filter Canister which reduces the noise level of the dust extractor to some degree, as well as providing much better, but still not good enough, fine dust filtering.

For the 20+ dust extractors I have tested there is no evidence that the pleated filter(PF) canisters are better than Needle Felt (NF) at filtering fine dust

Direct comparisons are tricky because there are several different types of NF and PF, and leaks from all filters confuse the issue.
There are no clear performance winners expect it appears on average, that the thinner NF filters (e.g. H&F) and cheaper PF perform at about the same filtration efficiency down to about 0.5 microns, and below that the cheap PFs are a few % better.
The thicker NF (e.g. CT) and more expensive PF perform at about the same filtration efficiency across the particle size range.

The cheaper PFs and thinner NFs BOTH suffer from the same problem of taking much longer to condition that their better counterparts.
By conditioning I mean partially clogged so they are more efficient at filtering fine dust.

The worst situation is when the are brand new. It takes roughly 3 hours to condition a cheap PF and up to 5 hours to condition a thin NF filter. These are a relatively long periods of time and the net result if the DCs are used inside the shed is that the shed will fill up with fine dust that unless ventilated will take days/weeks to eliminate. Given that it can take some months for a DIY to accumulate 5 hours of DC use this means that a she can be compromised for many months before the filters are conditioned. A quicker way to condition filters is to put a half a bucket of sawdust into the DCs collection bag and put the DC outside and let it run for a few hours. The swirly action of the air and dust in the collection bag will eventually mince the sawdust into finer and finer dust and condition the filters.

A similar situation applies when the filters are cleaned because it takes them some time to recondition - fortunately this is minutes instead of hours but it's more than long enough to recontaminate a shed.

But all of this pales into insignificance because of leaks. Just about every DC I tested leaked. The amount of dust coming out of the leaks was far greater than that coming through the filters and all this is why DCs and VCs should be vented outside a shed.

The advantages of a PFs over NF bags is not their filtration efficiency but because
- take longer to fully clog up.
- can be easily partially cleaned in situ and
- once conditioned PFs still allow for up to about a 10% greater airflow.

The extra flow is only significant if there is already a decent flow happening.
If the DC is using 4" ducting then the size of the ducting limits flow and adding PF to this sort of system won't gain a lot more airflow.
If the DC is using 6" ducting then this is less of a limiting step and now the flow can really benefit from using a PF.

Wow, thank you all for your input, just wanted to especially thank BobL and RoyG for their very detailed replies. This forum has simply blown me away, I've been on many forums over the years but none with members like this one, members so willing to give their time to provide amazingly detailed and helpful reply's.

Thank you again, I'm still struggling with my DC woes but I now have a far greater understanding and enough info to look at putting a plan in place.

Daz.

Originally Posted by Dazm

Wow, thank you all for your input, just wanted to especially thank BobL and RoyG for their very detailed replies. This forum has simply blown me away, I've been on many forums over the years but none with members like this one, members so willing to give their time to provide amazingly detailed and helpful reply's.

Thank you again, I'm still struggling with my DC woes but I now have a far greater understanding and enough info to look at putting a plan in place.

Daz.

No worries Daz, in the end you can only do what your budget and physical circumstances allow but there are a lot of misunderstandings out there about this topic.