< $1500 cyclone

[BobL]

There's a lot of cobbling that goes on in sheds and because i'm no different to most cobblers I actively encourage it. However, if there's one thing I know about air flow is that randomly putting together a motor of this, an impeller off that, and a cyclone of something, else plus a hurdy-gurdy of narrow ducting and choked machinery and expecting it to work efficiently is extremely low. It's like putting together a car using holden V8 engine, mini chassis, valiant gearbox and a ford suspension. While there's a good chance it will drive unless the components are optimised the overall efficiency will be poor.

If so many off the shelf DCs are far from optimised for efficient air flow (see my generic 2HP DC thread as an example) what chance has the average cobbler got of getting it right? There is a reason why Bill Pentz employed the services of several engineers to get his cyclone an setup optimised. A 3HP motor and small impeller on a standard BP cyclone is going to be far from optimal, the cyclone will have to be resized to suit the motor and impeller but it will still simply never achieve standard Clearvue type performance.

From what I can see there is also too much preoccupation by shedders on the DC especially when they are still running 4" ducting on choked machinery and a choked DC. The biggest bang for your $ is to fix those things first and then see how you go.

[aldav]

My reference was to their full size cyclones which are not available here

Point taken.

[meherenow7]

Hi. You've probably already done something about your dust issue, but thought i'd put my 2 cents worth in. I recently made my own cyclone base on a UK kit design made from perspex. It was a pain to make my own trying to figure out all the dimensions and materials, but was well worth the effort to make it out of perspex to see the dust get sucked in and get sucked down into the vortex generated by the cyclone.

My biggest issue is I made the inlet/outlet size to 100mm pvc pipe and being the only inlet on a 2hp dust extractor, you can hear that the motor is not running at full potential. So now I need to make another one to have one on each of the extractor inlets and let the motor be able to get up to proper speed.

I do wish I'd just bought one of these now on ebay. The inlet/outlet size should be better for the 2hp extractor to work properly and just bolt this thing onto a barrel or a bin and hook it up and your good to go. This listing has expired, but I know the seller gets more of these in, so maybe just ask when they will have one next.

There's no doubt all woodworkers should have a cyclone system of some sort. Since using mine, I put a new plastic bag on the dusty and there are a few sprinklings of dust in the bag and the rest goes in the cyclone barrel.

If only a manufacturer would incorporate a simple one into the dust extractor without being ridiculously expensive, it would sell like hot cakes.

[DaveTTC]

Hi. You've probably already done something about your dust issue, but thought i'd put my 2 cents worth in. I recently made my own cyclone base on a UK kit design made from perspex. It was a pain to make my own trying to figure out all the dimensions and materials, but was well worth the effort to make it out of perspex to see the dust get sucked in and get sucked down into the vortex generated by the cyclone.

My biggest issue is I made the inlet/outlet size to 100mm pvc pipe and being the only inlet on a 2hp dust extractor, you can hear that the motor is not running at full potential. So now I need to make another one to have one on each of the extractor inlets and let the motor be able to get up to proper speed.

I do wish I'd just bought one of these now on ebay. The inlet/outlet size should be better for the 2hp extractor to work properly and just bolt this thing onto a barrel or a bin and hook it up and your good to go. This listing has expired, but I know the seller gets more of these in, so maybe just ask when they will have one next.

There's no doubt all woodworkers should have a cyclone system of some sort. Since using mine, I put a new plastic bag on the dusty and there are a few sprinklings of dust in the bag and the rest goes in the cyclone barrel.

If only a manufacturer would incorporate a simple one into the dust extractor without being ridiculously expensive, it would sell like hot cakes.

Do you have pics of the one you made?

Dave TTC
Turning Wood Into Art

[BobL]

Hi. You've probably already done something about your dust issue, but thought i'd put my 2 cents worth in. I recently made my own cyclone base on a UK kit design made from perspex. It was a pain to make my own trying to figure out all the dimensions and materials, but was well worth the effort to make it out of perspex to see the dust get sucked in and get sucked down into the vortex generated by the cyclone.

My biggest issue is I made the inlet/outlet size to 100mm pvc pipe and being the only inlet on a 2hp dust extractor, you can hear that the motor is not running at full potential. So now I need to make another one to have one on each of the extractor inlets and let the motor be able to get up to proper speed.

The motor on a DC does not change speed substantially irrespective of the amount of air that flows through it unless the impeller itself is physically obstructed - i.e. jammed with rags or sticks or rope.
It's counter intuitive but the LESS air flowing (i.e. chocking the air flow) the LESS work the motor/impeller does (and the speed should be slightly faster when there is no air flowing through the impeller). If you don't believe use an ammeter up to measure motor current and choke the impeller inlet - the current drawn will be less than when the impeller is unblocked.
If the motor is not getting up to the proper speed then there is something else wrong with the motor.

I do wish I'd just bought one of these now on ebay. The inlet/outlet size should be better for the 2hp extractor to work properly and just bolt this thing onto a barrel or a bin and hook it up and your good to go. This listing has expired, but I know the seller gets more of these in, so maybe just ask when they will have one next

They are not much chop either. They are an old design so will add significant back pressure and reduce air flow.
With an inlet diameter of 117 mm this is going to be the limiting step.
To gain any sort of improvement to flow on a 2HP DC it needs to be modified (along the lines shown in the Generic 2HP sticky in this forum) to accommodate 6" ducting and 6" ducting needs to be used throughout the workshop and machinery ports need to be opened up to suit this as well.

There's no doubt all woodworkers should have a cyclone system of some sort. Since using mine, I put a new plastic bag on the dusty and there are a few sprinklings of dust in the bag and the rest goes in the cyclone barrel.

Unfortunately that doesn't mean as much as users think.

One problem is that as these types of cyclones physically restrict air flow so they don't pick up all the fine dust that they should pick up in the first place. Bill Pents has done some testing that demonstrates these small cyclone rob as much as 50% of the flow of a small system and my testing shows that chip collectors rob as much as 25% of the flow. Just dangling a hand in front of an air duct to assess airflow is unfortunately not an effective way of test flow. Accurate measurement of air flow is a lot more complicated than people think

Secondly it literally only takes a handful of fine dust to reduce the flow through the filters anyway. The manufacturers selling these units push the idea of not needing to clean the filters as often because the collection bags collect hardly anything. The reality is the small amount of really fine dust that blocks the filters easily bypasses the cyclone and reduced the flow through the filters. In terms of maximising air flow the filters need to be cleaned as often as the cyclone bin is emptied. Few people know about this and because they see only a handful of dust in the collection bag they think the filter is clean.

It's only natural that the average person concentrates on removing chips because it's what they see. With wood working dust the emphasis should be on maximising flow as this is essential to maximise the collection of fine dust in the first place, and then minimising blockages in the air flow pathway. So 6" ducting and no in line cheap cyclones or chip collectors, and yes you will have to keep filters clean or get a more professional cyclone like a Clearvue.

[meherenow7]

Do you have pics of the one you made?

Dave TTC
Turning Wood Into Art

Here's a couple pics from Iphone of my cyclone.
IMG_1117.jpg IMG_1120.jpgIMG_1246.jpg

[DaveTTC]

Bob, Is there any advantage to larger than 6" ducting with a home made 2 or 3hp system?

Dave TTC
Turning Wood Into Art

[DaveTTC]

Here's a couple pics from Iphone of my cyclone.
IMG_1117.jpg IMG_1120.jpgIMG_1246.jpg

Did you form the funnel or buy it that way?

If you formed it was it pliable material or did you heat and roll.

Dave TTC
Turning Wood Into Art

[BobL]

Bob, Is there any advantage to larger than 6" ducting with a home made 2 or 3hp system?

Dave TTC
Turning Wood Into Art

Short answer is no.
Even the biggest 3HP systems cannot move more than ~1400 CFM and that is with nothing connected to them.

The following is general advice - there are some very poor 3HP systems that are not as efficient as some of the better 2HP systems.

Adding 6" ducting immediately reduces the flow to ~1250 CFM, and adding machines to that drops it a bit more to around 1000 CFM.
100CFM is considered to be the minimum required to manage fine dust from one machine.

7" ducting has a theoretical limit of 1800 CFM but as the impeller cannot generate more than 1400 CFM that's the limit.
Adding machines to that drops it further to maybe 1200 CFM.
It would be good to have 7" but where do you get it?

8" has a has a theoretical limit of 2800 CFM but as the impeller cannot generate more than 1400 CFM that's the limit.
Adding machines to that drops it further, also 1200 CFM
8" is exxy but at least its more readily available.

HOWEVER
1200 CFM in an 8" duct means an AIR SPEED (in FPM - this is not the same as VOLUME FLOW RATE which CFM) of around 3500 FPM
This air speed is considered too low to be able to resuspend and clear sawdust that drops out of suspension during stalls and blockages.
Ideally you ned 4000 FPM to do this in a real world situation, problem is 3HP systems can't generate the flow to do this in an 8" duct.

This is why 4 and 5HP systems and 14"+ impellers are needed to generate say 1800 CFM at the impeller - Then you can use 8" ducting .
Then 2 machines could be extracted from at the same time and for big sheds this would clear residual dust much faster.

2HP systems are borderline even with 6" ducting but definitely suffer on 7" or greater ducting

[meherenow7]

Did you form the funnel or buy it that way?

If you formed it was it pliable material or did you heat and roll.

Dave TTC
Turning Wood Into Art

Hi, My cyclone build was based on this kit from the UK. http://www.cyclonecentral.co.uk/ I didn't want to pay the hefty postage to Oz so tried to replicate it myself.

I actually used a piece of HDPE plastic, not perspex as I said earlier, 1.5mm thick, which I could bend into shape without any heat. A 1200x2400 sheet was about $90, but in hindsight it was quite stiff and 1mm would have been fine and a lot easier to work with.

I used a cone calculator off the net to get the radius and dimension then scribed the plastic sheet basically with a big compass. Once it is scribed a couple times you simply run the stanley knife along it a few times and cuts through clean. To join the cone it was a 5cm strip of the same material glued with acrylic glue and then riveted to make sure it stays put.

I managed to find some of the same glue they use on the UK Kit, but with the 1.5mm plastic, it was too rigid with this glue and I snapped a second attempt at a cyclone.

Anyway, let me know if you want any more info.