Thread: Thien Baffle Dust Extractor

HS, I share your frustration. I'm reasonably new to woodworking and just making stuff with wood is all I wanted to do. People like BobL and Chris soon made me realise that with little effort I could soon put myself in the hospital. It's not hard to do so when manufacturers of dust collectors tell you "this is all you need to do woodworking" stories. The facts are there is so much INVISIBLE fine dust in the air where we use our machines we believe we are safe, however nothing could be further from the truth.
Most if not all wood dust is probably carcinogenic at worst and emphysema causing at best.
Possibly your best bet would be to buy a hepa vacuum cleaner to connect to your router or other power tools, via a chip collector is OK too, but if you go cheap with the vacuum you are risking your future health unless you put the vacuum fully outside your shop.
If you have a shop full of major tools you would need to look at a ducted system (big bucks) with the system also outside or isolated from your work area if it isn't hepa filtered.
The wash out is, if you value your health you need to become fully aware of how dust collection works and take nothing for granted.
Spend some time carefully reading the information on Bill Pentz's site which will probably better explain the full situation at:
Bill's Cyclone Dust Collection Research - Home Page

Look after yourself. Cheers, Ian

Originally Posted by Nanigai

. . . .
Most if not all wood dust is probably carcinogenic at worst and emphysema causing at best.

Actually I am not that pessimistic and I believe that there are far greater risks in home workshops and DIY activities than dust. The number 1 DIY tool responsible for most admissions into hospital emergencies, hospital admissions and deaths is the humble ladder. Fire is also a greater risk (How many of us even have a fire extinguisher, let alone an alarm in our sheds?) Indirectly the greatest cause of death from DYI will involve motor cars from DIY'ers making their weekend pilgrimages to their local hardware.

My obsession (there I have said it ) with dust is that I see so many DIYers buy a cheap vacuum cleaner or small DC or a mask and thing they have dust totally covered when something like a cheap vacuum cleaner makes things worse and most masks are totally inadequate. The most common thing that dust will cause is the development of allergies, some of which can be so severe that people will have to give up woodworking . If my rantings can help reduce this even by one person I reckon it will have been useful.

Most people are simply not in the cyclone league but for people on a tight budget the difference between venting even a small DC inside and outside a shed is very significant especially if the DC can be left to run for 20-30 minutes after the last dust making activity. Vacuum cleaners cannot vent outside a shed because they're low volume flow devices and have severe ducting length restrictions. I reckon cheap vacuum cleaners are nasty because they make more invisible dust than they capture. I think they should be banned from being used in shed.

Anyway - I'm just repeating myself

I think the woodworking community is slowly coming to appreciate the risks of the dust generated but it is a slow education process. Those that have addressed it have decided the cost no matter what it happens to be is not a factor when it comes to their long term health. If I put the question to someone to be a guinea pig in a long term dust test do you think I would get any takers? I am sure I would not but that is what people are doing. We need someone to go to a doctor and have their lung capacity tested and then engage in woodwork, five years later go back and see what the result is, any volunteers? Of course not but that is what we as a general rule are doing and no one wants to know the answer. Of course the above is a vast simplification and I only use it as an example of our stupidity as humans who think that they are bullet proof.

Originally Posted by Chris Parks

We need someone to go to a doctor and have their lung capacity tested and then engage in woodwork, five years later go back and see what the result is, any volunteers?

Chris, back in the 70's when I joined a mining company to work at their refinery I had to have chest Xray taken at the State Gov Xray center before I could start. Got tried of the nasty chemicals being used, so left after 4 years. Don't know what happened to that Xray, probably still stored in some gov warehouse in Perth somewhere.

Originally Posted by Chris Parks

We need someone to go to a doctor and have their lung capacity tested and then engage in woodwork, five years later go back and see what the result is, any volunteers?

A single person doing this is not going to do much. There are some people that have smoked their whole lives and are in their 80s and are OK.

What is needed is a (very expensive) extensive epidemiological study of hobby woodworkers. Medical researchers and authorities perform regular environmental scans on risky occupations and activities and tackle the ones they deem of highest priority. They also talk to medical experts and ask "What are you seeing in patients" . The fact that a study on hobby woodworkers has not taken place is an indication of the relatively small number of people involved and the risk i.e. LOW and/or being masked by other factors. Studies have been performed on woodworkers in industry and this is where the recommended 5/1 mg/kg dust levels come from. What is missing from these studies is particle size information. The fact they have not followed up on the woodworkers in industry suggests the risk is also relativley low.

Medical authorities are too busy tackling whole of population issues like obesity and diabetes to have time and resources to look at hobby levels of anything.

I understand the potential danger of 'invisible dust', but, among my many woodworking colleagues, I cannot name one who has definitively been adversely affected by this. That does not diminish the danger, but I agree with BobL that there are many more immediate dangers in the workshop, and high on that list is 'crap on the floor'. Sawdust in quantity on a concrete floor can be very slippery, and I do know folks, self included, who have been injured in this way. Therefore, to get back to the original post, it remains an excellent idea, by whatever method, to keep sawdust and shavings off the floor and in a dust collector, preferably one with a separator. I have found that a Thien-type unit attached to a 2HP dusty will collect most of the shaving produced by my Dewalt 733 Thicknesser, and this certainly makes my working environment safer. Therefore I value the obvious benefits of this system over any potential hazards that might arise from 'invisible dust', but, on the evidence, probably won't.

Originally Posted by adeben

I understand the potential danger of 'invisible dust', but, among my many woodworking colleagues, I cannot name one who has definitively been adversely affected by this.

While personal experience is useful is not something I would base such a decision on. We all know of someone who smoked and lived to be 90. I ran a poll on silky oak sensitivity and of the 50 odd responses 8 people reported a problem, 2 of these said they got by with adequate protection and 2 had to stop working with it.

Now to break my own rule about personal experience, one of the reasons why I'm a bit rabid about dust is when I was working outside with MDF in 2002 I lost my sense of smell for 6 weeks and it was not good. I then asked around and found out this was more common than I thought. My other reason is I have worked with dust since the early 1980s and so I can visualise invisible dust, it's components, sizes, generation movement and capture. Combine this with my woodworking hobby and the two experiences enable me to see pretty quickly when most hobbyists set ups are appropriate or not.

I will run another more comprehensive poll covering all wood dust and see what we get.

Originally Posted by Chris Parks

Headscratcher, a high volume low pressure system is what a generic dust collector is, something like this Jet® Dust Collector 1/2HP - Rockler Woodworking Tools

Thank you Chris this was what I was trying to find out, so the workshop equivalent of the vacuum cleaner (not literal) which is used with a cyclone like the one I built is called a "Dust Collector" (possibly also Dusty).

Thanks for the working link even though it is US based at least I now know know what I am looking at. Reading the reviews that one would seem quite marginal.

Now before we go much further let's sort some fact from fiction... While it would be great to live in an utopian world we have endless money and everything we want is at out finger tips lets look at one of my earlier statements.

Originally Posted by HeadScratcher

Couple of problems I have encountered so far... the first one is that I am finding it hard to get suitable hose that is bigger than about 40-50mm to collect the sawdust. Bunnings only seem to carry the larger sizes in hose that has holes all through it. So suggestions where I can buy 90mm or bigger hose in Sydney welcome.

If I can only find 40-50mm hose this rules out any possibility of a 150mm system unless somehow it is magically found somewhere between zero and 50mm.

No one has even asked how often I am going to use it... At this point in time I am only planning to build one set of speakers with this router. So far I have built a work bench, spent hundreds of dollars of miscellaneous work working items like clamps, router bits etc, and now I am been told I now need to spends thousands of dollars to buy the Rolls Royce of Dust Collectors to suck up the nth degree particles.

I am currently working outside because I don't even have enough room to get into my garage.

Somewhere along the line a bit of common sense needs to be applied. While I fully understand the argument for a no compromise extraction system, there needs to be a practical balance for the amount of work that is getting done.

Now lets get down to tin tacks. I have built the cyclone for very little money, but there must be some kind of home built solution that can compliment the cyclone without go commando over the top...

I don't need to draw the air hundreds of kilometres in fact the dust collector can sit right up against the work bench for as little as I plan to use it. I am also not overly concerned about filtration to 1 micron, but I am sure there has to be some kind of comprise that would do a half decent job for the 5 minutes I plan to use the router.

From what I can see the Dust Collector is just a big fan with some bags on it, surely this could be built for a reasonable price?

FYI... the reducer is not glued into place it is just sitting there in the photo. I have 2 90mm ends to play with. If necessary I could replace the centre outlet with a 100mm unit, which to my mind should create a greater vacuum inside if the inlet is 90mm.

The reason I can't go 100mm on the intake is because the 100mm bends are much larger than the 90mm ones which means it would have probably twice the volume between the lid and the fake bottom plate.

Bit more than I wanted to spend but I'm worth a few extra bucks...

How would this go with my separator?
Carba-Tec® 2hp Economy Extractor : CARBA-TEC

I could do a rebuild on the separator to do a duel 4" in and out.

Originally Posted by HeadScratcher

I am currently working outside because I don't even have enough room to get into my garage.

Somewhere along the line a bit of common sense needs to be applied. While I fully understand the argument for a no compromise extraction system, there needs to be a practical balance for the amount of work that is getting done.

As I had surmised you are working outside.

Originally Posted by HeadScratcher

Bit more than I wanted to spend but I'm worth a few extra bucks...

How would this go with my separator?
Carba-Tec® 2hp Economy Extractor : CARBA-TEC

I could do a rebuild on the separator to do a duel 4" in and out.

As you are working outside it should be OK.

If you ever get to set up inside your garage, keep the dusty outside.

Finally had a reason to chop up some wood, so I hooked up the Thien baffle I had made previously as a make shift separator.
As Bob predicted the 90mm pipe bends are too restrictive to make much of an impact. It did pick up a lot of MDF dust coming off the router, but left a fair bit scattered all over the table. It did noticeably reduce the amount that found its way onto the floor, and what didn’t make the inlet I just grabbed and threw towards the inlet.

It had reasonable suction at the intake, but certainly wasn’t going to suck my hand down the pipe. I pulled one of the caps off at the DC and it still had plenty of suction which clearly indicates that it has the capacity to support a larger diameter pipe.
It was quite interesting to watch the visible dust curve towards the inlet, but it was fairly clear more flow was required as some dust that went near the inlet didn’t have the flow rate to be pulled in. After cutting out the piece of wood shown on the table there was very little dust in the bag, just a tiny bit in the seam at the bottom of the bag. I would call the project a reasonable success but to make this size Thien baffle work, it would probably need one on each of the three outlets on the DC.

Onward and upward, still yet to make any further progress on the Ultimate Dust Extractor.

Lets take a step back before the baby got thrown out with the bathwater.

Small cyclonic dust seperators used with either houshold or workshop vacs are very viable and practical, I have been using some sort of arrangement like this for over 15 years.

If you are working with routers and sanders that run small 1 1/2" extraction connections you nee no more than standard vac hose.stepping up to 2 inch dust extraction hose for longer runs is worth while but you will have to go back down to standard vak hose to connect to the machine.

For extracting sanders, routers and other hand held tools you need high pressure low volume suction as you will get from a vacuum cleaner.

Adding some sort of seperator will stop your vaC from clogging up nearly as fast.

You have to be better off running some sort of extraction, imperfect though it might be that bathing in all the dust that otherwise spews out of these machines.

So back to the project.

You have the right idea but there are some important details.......

You will be getting big losses because of the right angle bends in the system.

Ideally the input to your cyclone should be radial and in a straight line for at least the diameter of the cyclone before it enters the drum.
so getting the whole baffle structure above the waste bucket is best.
If you must come in from the top, do so at and angle with a straight pipe or a heat bent pipe with no sharp bends.

the centre outlet will be more efficient if it is significantly larger than the inlet.....so if you have a 2 inch inlet a 4 inch outlet is good.......but a 2 inch will work...but take it straight up not thru a sharp bend.
Lets not get all bent out of shape fellas......
what we are trying to do is slow the air speed in the outlet....the 4 inch centre piple can be braught above the top of the baffle assembly 4 or 6 inches..the more the better and then adapted down with a plumbing reducer to the 1 1/2 or 2 inch pipe to go to the vac.

so here is one way of making what you are trying to do a little easier.

make the bottom baffle piece to fit the top of the bin like a bin lid.....two thicknesses of MDF one to sit on top and one to sit inside the rim...you get the idea.....cut ya slots for ya baffle..or cut a complete hole and arrange ya baffle on threaded rods or what ever.

ya then have to build an inverted bucket of some sort.

a 15 liter metal drum or a big plant pot could be adapted, but ya want some sort of radial inlet...which is a bit of a fiddle...but that is where the efficiency will come from.

If the upper bucket tapers out from the top to the bottom that will make this type of cyclone more efficient...the particles will spin out and down.

Before I built my mini cyclone I used a commercilly built item I liberated from an inbuilt vac system.

I'll attach a picture of the item in question that I have recently pressed back into service with a vac that was liberated from the house when the new wonder vac was purchased.

If the whole "Invisable Dust" thing worries you, sucking on the thing with a HEPA filtered vac is one answer......the cyclone willsimply slow the normal bag and filters from clogging up.
OR the Vacuum cleaner has a convienient hose that means the seperator can be inside with you and the tools and the vak can be outside.

cheersvacbox.jpg

The Thien baffle was really a fore runner to something decent. When I built it I didn't know a great deal about what was required or how much flow I would need. The design is an intrepted copy off the web, but as you suggest there are gains to be had by at the very least feeding it from the side.

The inlets are only 90mm not a 100mm which the hoses are supposed to be, but there is some funky measurements going on there. I thought since I had already built it, there was no harm in hooking it up since I dont have a high flow cyclone design finished or built. As much as anything it does give me an indicative idea of how much vaccuum / flow is required to really do a half decent job with a dusty tool like the router.

However I am inclined to agree with Bob with his 6" cures most woes theory. Considering how little dust made the filter / collection bag on the 3HP DC, it does say something about the dust separation efficency of the Thien design.

Would be intersting to scale it up to a 150mm side inlet, and 150mm outlet above the collection bin. I have a 150mm right angle and some 150mm straight, but no 150mm hose at present.