Thread: 1000 c f m

Originally Posted by doug3030

Confuscious says: Man who says it can't be done should not interrupt man who is doing it"

A little harsh perhaps?

At this point I will extend my thanks to all and sundry that have posted on this thread, the information that has been posted is fantastic. my father taught me to ask "WHY IS THIS SO" when dealing with ingrained idea's or attitudes. I have read Chris parks, Mini to name few prior to 2006 were dust extraction was talked about in length. and it all ways came back to the blower being the problem or the lack. I do not have a high education in a grade 10 drop out, but what I have real world experience and the want to learn more.

To you Sir Mr BobL. I say this with respect and i'm not attacking you, when you joined this site in Feb 2006 why did you have to ask how to setup a dusty, if you have had all this background knowledge.

As I believe It is our nature as humans to ask even if we do know the outcome, as I have said lets improve what we have got without having to get the grinder out and cut up $500 unit. lets start saying this is not good enough WE need change.

Respectfully

Gary Raymond Lacey

Originally Posted by BobL

The trade off is the pleated filter would have to be kept clean.to maintain this air flow.

So we're back to the perennial problem. The filter has to be kept clean. What does 'clean' mean? The cleaning interval obviously would vary depending on the machine you were using. If the DC is located outside the shed (the ideal for hobbyists) how many people are going to be putting in the cleaning effort required to maintain >900 cfm? Not many I'll bet. Once the filter is 'dirty' the flow rate drops dramatically.

I acknowledge what BobL has said about a proportion of the fine dust not being trapped by a cyclone and therefore getting to the filter and clogging it over time. That problem is very apparent with the small vac cyclones I sell. Having said that though the amount of material that you can put through a Dust Deputy or similar compared to what a vac can achieve without it is simply staggering. Yes, over time suction is reduced, but you can collect over 40 times more material before cleaning is needed.

What's the best way to go? I don't know. Like many things perhaps it's horses for courses. Doug seems happy with his setup and if he's achieving a consistent 850 cfm at the machine I for one think that's pretty good for a 2HP dusty. 1,000 cfm would be nice though and with a move to 3HP should be possible, if only there was a machine with the right hardware specifications to achieve it.

Originally Posted by Opelblues2

At this point I will extend my thanks to all and sundry that have posted on this thread, the information that has been posted is fantastic. my father taught me to ask "WHY IS THIS SO" when dealing with ingrained idea's or attitudes. I have read Chris parks, Mini to name few prior to 2006 were dust extraction was talked about in length. and it all ways came back to the blower being the problem or the lack. I do not have a high education in a grade 10 drop out, but what I have real world experience and the want to learn more

I disagree that the blower is the main culprit.
Air is a viscous fluid that is difficult to move through small openings and pipes and using a more powerful blower is not really the way to go
At least 6" ducting is needed to move the amount of air required and the fact that machines are supplied with small ducting ports makes then a major impediment to flow.
To get the required airflow through a 4" pipe the blower would need to be massive (20HP?) cost about $10k and sound like a jumbo jet.

Blaming the blower is a bit like blaming the fundamental laws of physics. A certain amount of energy is needed to accelerate any object (including air) and the amount of energy cannot be made less than that, otherwise it would be like getting more energy out of s system that is being put into it. . That is why there are likely to only be marginal improvements made in the efficiency of fan designs i.e. cannot get more than 100% efficient. Major improvements in dust collection may have to come from a different direction, maybe something like electrostatic precipitators or using ways of cutting and shaping that don't produce as much dust, laser cutting?

To you Sir Mr BobL. I say this with respect and i'm not attacking you, when you joined this site in Feb 2006 why did you have to ask how to setup a dusty, if you have had all this background knowledge.

That is a good question - slow learner I guess?

Like many others I was woodworking for many years for an average of a few hours each weekend in a small shed, often ankle deep in sawdust.
Meanwhile at work (as far back as 1980) I was involved in projects setting up ultra-clean dust-free laboratories but made no connection between the two situations.
My woodworking gear in those days was limited to an 8" TS, a 4" jointer and a few power tools.

In 2002 I made a large desk in which there was MDF and lost my sense of smell for 6 weeks even though I was working mostly at outside - that should have been a wake up call but I then got involved with various projects at work and wood working went on the back burner for a while,

In 2005 I started installing an attic and attic ladder in the house - the roof space was filthy and already very dusty and woodworking in that space had me wearing masks for a fair time during that construction - I still had not made the connection between what I was doing at work and the dust in this space.

In 2006 I decided to set my shed up for some easier woodworking so for the first time I made a woodworking bench. I also found WWF and this showed me that it was not necessary to work ankle deep in sawdust. But still no connection to work related stuff and this is why I asked for ideas on the forum for setting up a DC.

Like most people on a budget I started with a 1HP blower and 4" ducting and tried to use it to service a 12" table saw, with it and found myself still ankle deep in sawdust and a constant layer of dust over everything in the shed, even after I cleaned up.

I did work out, without reference to anyone else, that the best place for a DC was outside and I did post about this. This made a small difference to the dust layer but not that much.

In 2007 I found BPs websitsite and only then realised I had access to all the measuring gear needed to assess woodworking dust and air flow etc through work.
I remember measuring the air flow through the 1HP DC and being very depressed when it showed that it was only drawing around half of the manufacturer rated flow.

Then I got side tracked by milling timber (6000+ posts on a small milling website) from about 2007 to 2010.

In 2010 I put in place some retirement plans and decided I needed a bigger shed and one that was better able to cope with wood dust. I had read Bill Pentz website and started to use some of the gear from work to make dust measurements for myself. Only they did what I had done at work suddenly click and the more I thought about it the stronger the connections became.

In 2012/13 I did a survey on the efficiencies of DCs in about 20 home workshops in WA. This was very revealing and I have posted some of the results on this forum.

So my voyage through woodiest has not a good example to follow but no doubt many woodworkers will do the same because it's only when we are ankle deep in dust and nothing we do seems to keep that dust layer from forming over everything that we maybe start to do something about it.

Originally Posted by aldav

So we're back to the perennial problem. The filter has to be kept clean. What does 'clean' mean? The cleaning interval obviously would vary depending on the machine you were using. If the DC is located outside the shed (the ideal for hobbyists) how many people are going to be putting in the cleaning effort required to maintain >900 cfm? Not many I'll bet. Once the filter is 'dirty' the flow rate drops dramatically.

Yep - perennial problem and one that may would drive many including me to setting up a BP style cyclone if I was doing more woodwork. Despite my retirement plans I'm haven't been doing much WW in the last few years and only empty and clean my DC bags (twin bag setup) about 3 times a year and even then they are only maybe 1/3 full. I do have a pressure gauge on my filters and this does help determine the pressure loss.

I acknowledge what BobL has said about a proportion of the fine dust not being trapped by a cyclone and therefore getting to the filter and clogging it over time. That problem is very apparent with the small vac cyclones I sell. Having said that though the amount of material that you can put through a Dust Deputy or similar compared to what a vac can achieve without it is simply staggering. Yes, over time suction is reduced, but you can collect over 40 times more material before cleaning is needed.

Waiting for the filter to block before cleaning is a bit like waiting to get petrol until you completely run out.

Unless pressure or flow measurements are made, users of chip collectors and small cyclones (that still use filters) have no idea how much their filters have clogged and what the resulting loss of flow has occurred.
It is simply impossible to tell by feel or eye how well a DC is sucking especially where higher flow rates are involved.
Flow rates drop off well before filters are clogged and I recommend uses of chip collectors still empty the small amount of dust that gets into the plastic collection bag and clean their filters at least every other time they empty their collectors. It does not even have to be a full clean, just shaking the filters so the dust falls into the collection bag and empty that bag.

There may well only be a teaspoon of fine dust in the plastic collection bag underneath the filter it doesn't take much fine dust to block a filter. Running a partially filled DC without actually collecting any saw dust will still block a filter because the dust in a collection bag will be swirled around and around continually making fine dust. This is where a good cyclone really does help.

What's the best way to go? I don't know. Like many things perhaps it's horses for courses. Doug seems happy with his setup and if he's achieving a consistent 850 cfm at the machine I for one think that's pretty good for a 2HP dusty. 1,000 cfm would be nice though and with a move to 3HP should be possible, if only there was a machine with the right hardware specifications to achieve it.

Doug is lucky he can vent his DC outside, otherwise in most situations filters would still be required.

I'm not against chip collectors - just reporting what I measure. For those of us that still have to use filters adding a chip collector will immediately reduce the flow. Of course the filters have to be kept clean whether a chip collector is used or not.

My observation of the 20 or so workshops I visited during my dust study is that chip collectors made no visible difference to the levels and layers of dust in a shed.

Well, Well, Well,

After prods, nudges, pokes, Groogy has enough information to cut and paste to the FAQ page, keeping him busy for a week

I also have ideas on how to proceed with a water scrubber,rain shower, design ( no dark magic)

I love the head banging smiies, thanks Doug.

I am in communication with a hygiene specialist to provide back up to data for tests.


Cheers Barry

Originally Posted by BobL

Did you ever post details your DC3 bore out mod - I don't recall seeing anything about it on the forums. I realise not everyone posts everything they do but I have been interested in seeing when and how this is done.

Hi Bob, no I did not post about the mods I did on my 2hp dusty and I will try to explain why.

First of all look at this thread - https://www.woodworkforums.com/f200/generic-2hp-dc-171247 (Happy 2nd birthday to the thread, BTW)

Have a read of post #3. This post is the earliest reference to how to mod a 2hp generic dusty that I can find on the forum. I was the author of this post. In it I give a very comprehensive explanation of what I was planning to do to my dusty when I found time. It was complete with measurements of existing inlet and outlet ports and proposed modified sizes. All the info on how to do the modding of the impeller unit are right there in that post and were my own original idea.

Now look at post #5. This is where you were telling me that despite my enthusiasm, my idea was flawed. Then, Nob, you went and made the modifications as detailed in subsequent posts in the thread, firstly the inlet, then by removing the choke point on the outlet, just as I had suggested in post #3, and you found out that the mod was so successful you have referred to it in many subsequent threads. In fact it has become known as "BobL's 2hp dusty modification" even though it was Doug3030 who first put the idea out there. (no sour grapes here BTW, you did the mod first and documented it all professionally)

I am pleased you went ahead and did it before I had a chance to do so Bob, You had the skills and equipment to run proper testing. The modification had been proven. I could then go ahead and modify mine with the knowledge that it was well worth doing.

I did not follow on with the mod to the ring, filter and bag because that was not how I was proposing to use my impeller. Also in Post #3, I explained about venting it outside directly from the outlet port of dusty.

Anyway, Bob, the mods you did to your impeller unit were pretty much identical to mine, so I saw no real need to do a WIP on the process. You had already done that and had also the advantage of being able to post accurate results.

There are many things that I do in my shed that I do not post on the forums for various reasons. One of those reasons is that there are some topics on the forums that you know that no matter how good your idea is for your own particular application and circumstances, you are going to be criticized for it by the local self-appointed expert, who with no personal knowledge of your shed, equipment or the type of work you do, applies his own standards to your situation.

Bob, I have learned a lot from you on the forums, as have a lot of other members. You strive for perfection and set the bar high. Please continue to do that. But please also accept that not all of us are trying to achieve the same as you. We all have different aims and different requirements.

Anyway thats enough on this for me for today, I have an afternoon date with a 21" bandsaw and a sheoak log in my carport.

Cheers

Doug

Originally Posted by mannum3

Well, Well, Well,

After prods, nudges, pokes, Groogy has enough information to cut and paste to the FAQ page, keeping him busy for a week

I also have ideas on how to proceed with a water scrubber,rain shower, design ( no dark magic)

I love the head banging smiies, thanks Doug.

I am in communication with a hygiene specialist to provide back up to data for tests.


Cheers Barry

Sorry but I see anything new in this thread that is not already on this forum somewhere.
Certainly nothing that is worth putting in the sticky, there are no measurements or experimental confirmation of anything, just a few general statements and claims.

Originally Posted by doug3030

Hi Bob, no I did not post about the mods I did on my 2hp dusty and I will try to explain why.

First of all look at this thread - https://www.woodworkforums.com/f200/generic-2hp-dc-171247 (Happy 2nd birthday to the thread, BTW)

Have a read of post #3. This post is the earliest reference to how to mod a 2hp generic dusty that I can find on the forum. I was the author of this post. In it I give a very comprehensive explanation of what I was planning to do to my dusty when I found time. It was complete with measurements of existing inlet and outlet ports and proposed modified sizes. All the info on how to do the modding of the impeller unit are right there in that post and were my own original idea.

Now look at post #5. This is where you were telling me that despite my enthusiasm, my idea was flawed. . . . . .

I do remember your post and suggestions but cannot recall how much of it entered my brain at that time. At the time I was nearing the end of my DC testing experiment and only originally planned to check its efficiency. Then I realised it had not been used for 3 years and (2 years on still has not been used) so why not experiment with it.

One thing I cannot see cannot see in that post is the word "flawed"

Here is what I said was

Doug , I really like your enthusiasm and your suggestions are indeed good ones and will improve things, but I doubt it will improve things as much as you hope.
The one KPI that tells me this DC has very little left in the tank is the static pressure of 7.2" of H20. This is for a choked naked impeller (this is the standard way it is done) and no amount of flow improvement will improve this figure, in fact if one is not careful any modification could make things worse and reduce the available pressure..

I still stand by the statements above.
It's not just the max SP for the generic 2HP motor impeller (which on repeat measurement turned out to be 8.1" i.e. not that different to some 3HP units), it's the fan curve which is limited which is why it doesn't handle back pressures as well as the bigger motor impeller combos do and this means
- it cannot make the most of 6" ducting, which can carry 1250 CFM
- it cannot support long lengths of ducting or multiple junctions
- it does not handle restricted machinery.

Even though the modifications produced a ~50% improvement in the flow t is still only 840 CFM which is why I still don't believe the modified 2HP is really an answer to DIY WW dust.
The reason I did the modification was to see how much better it could be made.
If you have a 2HP DC is it worth modifying it? Of course it is more CFM = BETTER.

I also posted BPs Fan curves which included a couple of 2HP DCs (blue and green lines on the graph)
They rate as "fair" provided they loses no more that 4" of WC.
It's very easy to lose 4" of SP especially if a chip collector or long ducting is added to these DCs.
The worst I have seen on a standard 2HP DC is many metres
of 4" ducting with a large chip collector and the flow was <200 CFM trying to service a large thicknesses and the guys shed was ankle deep in fine dust.



Anyway back to my original question about posting your mod.
Let me quote the forum mantra, "no pics means it didn't happen".

What would be interesting to see is the bewilderment of the Carbatec purchasing manager seeing a huge spike in people ordering 150mm hose!

I've already 4 metres in my cart and I'm only hesitating as there are a few tooooo many other things in there "I need"

It rasies the question of exactly how I'm going to open up all those 4" ports on the gear... (but I'm REALLY looking forward to it on the lathe!!!!)

Originally Posted by BobL

Sorry but I see anything new in this thread that is not already on this forum somewhere.
Certainly nothing that is worth putting in the sticky, there are no measurements or experimental confirmation of anything, just a few general statements and claims.

I do not wish to preach to the choir, but

FAQ are located at beginning of the Dust Collector section of the forum.

I recall reading a certain individual saying he was sick of answering the same questions over and over again.


Do you really, really, believe that a post in this thread of 22 May 09.30 pm would not be valuable to a "newbie" located in the FAQ.

Then if the newbie then asked "who is this author? what does he know? what has he done", a background briefing given on this thread

would be of little value?

Cheers Barry


printed words do not carry emotion, I love smilies thanks Doug for pointing me in the right direction

above comments made Tongue in Cheek no offence intended.

Sorry re post above,

When I replied I referred to 22 May 09.37 pm last time I looked it was 22 May 08 .07 pm

I see on the right side of screen the posts are numbered, I am referring to post #68 on this thread

Cheers Barry

I think Barry's right, there is some valuable information here that many forum members would find helpful. Apart from post #68 there is also this, "It's not just the max SP for the generic 2HP motor impeller (which on repeat measurement turned out to be 8.1" i.e. not that different to some 3HP units), it's the fan curve which is limited which is why it doesn't handle back pressures as well as the bigger motor impeller combos do." The only time I've seen a compelling argument to prefer 3HP over 2HP.

We need to remember who the audience is - we're talking to woodworkers here, not someone who wants to take up dust extractor design and testing as a hobby. It may well be that there is nothing here that does not appear elsewhere on this forum, but to have the information all available in one place and presented in a systematic, cogent, easily understood manner would surely be of value to many members.

David

Good Morning,

I have sent a PM to Groggy advising him of this thread, whether or not he uses the information is up to him.

Let's us all move on,

" You can not re-invent the wheel ", but boyoboy the ride is smoother today.

Cheers Barry