Thread: DC advice

The photo shows it's a "Sher Power Tools" brand which might be a precursor to the Sherwood brand.
It does look like a DC-7 and I suspect Sher just called their 3HP DC " DC3HP" and I have vague recollections that their 2HPDC was called "DC2HP".

It should move enough air for a basic DIY setup. How big is your shed?

Thanks Bob.

I was thrown, as the unit has a 12" impellar. I thought id would be larger.

Shed is about 7.6 x 6.0m, with 3m celings. My plan is to connect 6" PVC direct to everything, and customise the collection points on each machine. Unfortunately the set up will have to include a CDS 2/3 cyclone for collection. However, i'll be exhausting the rest of the fine dust outside. My hope is that this doesn't result in too much being ejected, though i don't have high hopes. I've toyed with skipping the cyclone altogether, and just exhausting everything into some kind of outside box (i have a 4x7x1m space under the house i could possibly use to make a containment box). However, i don't know how i would successfully vent this, while containing the majority of the dust. I've been racking my brain trying to come up with the best scenario, but without spending 4k on a Clearvue there seems to be compromises everywhere.

Thanks for the info.

It has what they call a deep vane impeller - it has more air flow but not at a significantly greater pressure than most other 12" impellers.

That CDS 2/3 is gonna stymie the flow on that small diameter impeller and it may not work very well at separating this fine dust.
That size impeller needs about a 20" diameter cyclone to get decent separation.

It depends on how much dust you make but for basic DIY work honestly I would live with cleaning the filters on a unit like that,

When you say exhausting the fine dust outside, do you mean you'll vent directly to outside? ie no filter? or will have an outside enclosure that vents externally?

As I found that the CDS, doesn't do a great job at separating dust and you'll still get quite a bit of dust in the DC collection bags, meaning if you're venting directly outside with no filter bags/canisters you'll be spraying a visible spray of dust.

Cleaning the filters is the way to go, not only does this maintain airflow, but also allows you to keep an eye on how full your dust collection bags are.

I

Thanks Bob and tonzeyd for the replies.

To clarify, what i was considering in my earlier posts was to either:
a) use the cyclone inside the shop, with the DC attached direct to the cyclone outlet, and vent the "fine" dust from the outlet on the DC straight through a wall;
b) use the cyclone inside the shop, with the DC attached direct to the cyclone outlet, and vent the "fine" dust from the outlet on the DC straight through a wall into an outside enclosure that vents externally; or
c) to skip the cyclone altogether and vent to an outside enclosure that vents externally.

Also, with regards to the "external enclosure", i would have the option of using the space under the house i mentioned in my previous post to construct something. My initial thoughts were that c) would not be feasible, but i put it out there in case others could expand on my rudimentary idea.

Its a pitty about the CDS, though not a surprise that it doesn't separate effectively. I'm definitely all for taking the advise that you guys can offer. To be clear, do you think my best option is to simply use cartridge filters, with no cyclone? Reading Bill Pentz's site gave me the impression that internal filters should be avoided if possible. I do cut up some awful products like MDF (shelving), so i could imagine the filters getting clogged quite quickly.

I've been looking into the plans for making Bill Pentzs cyclone design. I like the look of this, but i've been avoiding going down that path if can make a simpler setup, without compromising too much. From what i understand if i were to use Bill's design, i could maintain efficiency, increase the time between filter cleaning, or simply vent directly to atmosphere. Is there a reason more people don't just use Bill's design to build their own cyclone?

Originally Posted by skullmonkee

To be clear, do you think my best option is to simply use cartridge filters, with no cyclone?

Yep.

Reading Bill Pentz's site gave me the impression that internal filters should be avoided if possible. I do cut up some awful products like MDF (shelving), so i could imagine the filters getting clogged quite quickly.

Sure,
BUT
Given the same motor/impeller size, initially twin bag filters enable more flow than any cyclone especially if you use pleated paper filters. Don't forget that Bill Pentz is speaking from a position of someone using his specially designed cyclone which efficiently separates out most of the dust. Using the CDS is a different kettle of fish.

I find you don't have to repeatedly clean the filters to get reasonable air flow performance, just give them a good rattle or shake before you start major dust making. This causes much of the caked up dust on the filters to fall off the filter down into the collection bags. The filters themselves can be given a more thorough clean when you empty the sawdust out of the collection bags. The more often you do this the better but I would recommend the collection bags NOT be allowed to go beyond half full. The fuller the collection bags get the more dust it thrown up into the filter bag space and that's what quickly clogs the filters.

Also there's no need to clean the filters back to new condition. The filters still work efficiently when they are conditioned with some fine dust in/on them. The dust itself actually provides better filtration that no dust. Wearing a mask I just shake off all the dust off the filter into my council wheelie, and pick off any large curlies that have become stuck (embedded) in the filter.

I've been looking into the plans for making Bill Pentzs cyclone design. I like the look of this, but i've been avoiding going down that path if can make a simpler setup, without compromising too much. From what i understand if i were to use Bill's design, i could maintain efficiency, increase the time between filter cleaning, or simply vent directly to atmosphere. Is there a reason more people don't just use Bill's design to build their own cyclone?

A) One reason is that the minimum BP design still requires a 4HP motor which can be run from a VFD of single phase 240 but it should still be run from a 15A GPO. not everyone has one of these.
B) Another reason is the height of a BP design especially if you want to fit a decent size sawdust bin under the cyclone.
C) If your shed is small (so no long ducting runs) then a 3HP DC that vents outside it usually sufficient to extract the dust generated by basic machines under DIY conditions.

I had a problem with B) and so I went with C) and have measured my personal dust exposure with dust particle counters when using basic machines and am completely comfortable with the ability of my 3HP DCs ability and support ventilation systems to indefinitely remove the dust from my shed.

The downside is cleaning the bloody filters and I do swear every time I have to do it. I'm lucky that I don't actually make a lot of wood dust so I don't have to empty the bags very often. If anything I'm making more metal dust these days and that s another story. For someone that makes a lot of dust they have to determine if they are prepared to clean filters or would prefer to have a filter free system.

Originally Posted by skullmonkee

I've been looking into the plans for making Bill Pentzs cyclone design. I like the look of this, but i've been avoiding going down that path if can make a simpler setup, without compromising too much. From what i understand if i were to use Bill's design, i could maintain efficiency, increase the time between filter cleaning, or simply vent directly to atmosphere. Is there a reason more people don't just use Bill's design to build their own cyclone?

The main emphasis should be on "bill pentz design" not inspired by bill pentz. Bill Pentz cyclone is highly efficient for a reason and thats due to loads of testing and refinement, so unless you've got the time and skills to know how to improve the efficiency of a your home made cyclone I wouldn't bother with attempting to DIY his cyclone. I've also tried contacting a few sheet metal guys to make one for me and I ended up either being flat out rejected or wasn't cost effective especially when you consider the fact that you'll still need a sufficiently large impellor/motor combination to make the most of the cyclone. In the end, i went with a 3hp unit and have no regrets... still do think about getting the clearcue from time to time.

The other reason why people don't build their own is there are loads of people who either believe dust extraction = broom stick or do not spend enough time in the shed to justify the cost associated with getting a dedicated dust extraction system, as most DIYers would prefer to buy tools rather than spend the money on DC.

My on the other hand, prefer not to take the risk of getting cancer allergies etc and would like to be able to enjoy making stuff for as long as i can.

If you can get hold of a 15" impeller and 4HP motor a DIY BP cyclone is not that hard. I personally know two blokes that have built their own. One fitted a 3HP 12" impeller and so it does not work all that well. The other one is working OK except the fella has mainly used 4" ducting and done nothing about his machine ports.

Protection from exposure to wood dust is not a magic bullet operation. There are a minimum number of ducks that need to be lined up for a DC system to work and in many DIY situations chooks can be used in place of ducks. The biggest chook that can be employed is ventilation. To be effective at all times it cannot be passive (ie leave the doors open) and so needs to be forced. I am really surprised this is not employed more often.

Also there's no need to clean the filters back to new condition. The filters still work efficiently when they are conditioned with some fine dust in/on them. The dust itself actually provides better filtration that no dust. Wearing a mask I just shake off all the dust off the filter into my council wheelie, and pick off any large curlies that have become stuck (embedded) in the filter.

Thanks Bob. I'm definitely going to look into filters.

A) One reason is that the minimum BP design still requires a 4HP motor which can be run from a VFD of single phase 240 but it should still be run from a 15A GPO. not everyone has one of these.
B) Another reason is the height of a BP design especially if you want to fit a decent size sawdust bin under the cyclone.
C) If your shed is small (so no long ducting runs) then a 3HP DC that vents outside it usually sufficient to extract the dust generated by basic machines under DIY conditions.

I had a problem with B) and so I went with C) and have measured my personal dust exposure with dust particle counters when using basic machines and am completely comfortable with the ability of my 3HP DCs ability and support ventilation systems to indefinitely remove the dust from my shed.

By the above, do you mean you use your 3HP DC to vent outside to a collector, or just vent all material directly outside?

My on the other hand, prefer not to take the risk of getting cancer allergies etc and would like to be able to enjoy making stuff for as long as i can.

Thanks tonzeyd. I have the same opinion, so i want to take every precaution that i can.

The main emphasis should be on "bill pentz design" not inspired by bill pentz. Bill Pentz cyclone is highly efficient for a reason and thats due to loads of testing and refinement, so unless you've got the time and skills to know how to improve the efficiency of a your home made cyclone I wouldn't bother with attempting to DIY his cyclone. I've also tried contacting a few sheet metal guys to make one for me and I ended up either being flat out rejected or wasn't cost effective especially when you consider the fact that you'll still need a sufficiently large impellor/motor combination to make the most of the cyclone. In the end, i went with a 3hp unit and have no regrets... still do think about getting the clearcue from time to time.

I've read a couple of articles on people making their own. I think its something i could spend some time on getting right (assuming i could use the filters by themselves in the meantime). I think id look to get a secondhand 4 HP unit and run it from one of my 15A outlets with a VFD. Of course, this is assuming that when i crunch the numbers its cost effective. When you looked into DiYing Bills design, was it from the plans on his site?

If you can get hold of a 15" impeller and 4HP motor a DIY BP cyclone is not that hard. I personally know two blokes that have built their own. One fitted a 3HP 12" impeller and so it does not work all that well. The other one is working OK except the fella has mainly used 4" ducting and done nothing about his machine ports.

This gives me hope. I guess my revised plan is now to do the following:

- 6" tubing to everything, with customised collection points at machines
- Skip the cyclone
- Use the 3HP unit with a pair of pleated filters and clean the filters regularly. Both the unit and filters will need to be inside the shop, mainly because of noise. Is this a no-go since this type of filter doesn't get the <0.5 micron dust?
- Look into DIYing a BP cyclone, and pairing it with with a secondhand 4HP motor (15A and VFD). I might be able to source a 5HP instead. I'd assume there would be no issues with a 5HP?
- If i end up going the DIY BP cyclone route, i can choose to vent to atmosphere or vent to the filters, depending on whether i want to recirculate conditioned air.
- On top of all of this, i think i'm going to install a large extraction fan in the wall to vent the room to help with the fine dust that escapes at the tool.

Finally, a couple of further questions:
- do you have any recommendations for filters? I've read up on Wynn filters, but cant find anything about them in Australia.
- In your experience, are higher power DC's much louder than 3HP? I'm already thinking about dampening the sound with an enclosure.

Really appreciate all the pointers.

Originally Posted by skullmonkee

By the above, do you mean you use your 3HP DC to vent outside to a collector, or just vent all material directly outside?

My entire 3HP DC twin collector bags and twin needlefelt filters are outside in a HD enclosure - saves on a lot of room inside my shed. My DC has very efficient filters and the way the filters and bags are fastened they self seal so the air coming out of the DC has usually been very clean provided I don't reuse the plastic collection bags (see below). I have all the testing gear and experience needed to test for airflow/dust leakage etc.

- 6" tubing to everything, with customised collection points at machines
- Skip the cyclone
- Use the 3HP unit with a pair of pleated filters and clean the filters regularly. Both the unit and filters will need to be inside the shop, mainly because of noise. Is this a no-go since this type of filter doesn't get the <0.5 micron dust?

Noise is an important factor. Most filters materials are usually pretty efficient and collect most of the dust even down to 0.3 microns, the problem is that many DC components end up leaking and some are worse than others. The standard spring loaded toggle clamps around bags are rubbish. DCs that are towed around a shed and crash into stuff tend to be much leakier than DCs left in the one spot especially f they are surrounded by and enclosure. Sawdust is abrasive and if the bag contains a lot of sharp chips and the plastic collection bags are left too long with the air going round and round ie not collecting dust, the sawdust will wear or puncture pin prick holes in the collection bag. The longer a collection bag is left on the greater the likelihood of leaks. If all this happens outside it doesn't matter.

- Look into DIYing a BP cyclone, and pairing it with with a secondhand 4HP motor (15A and VFD). I might be able to source a 5HP instead. I'd assume there would be no issues with a 5HP?

You'd need to get a 5HP VFD but they don't cost a lot more than 4HP VFD.

- If i end up going the DIY BP cyclone route, i can choose to vent to atmosphere or vent to the filters, depending on whether i want to recirculate conditioned air.

Correct

- On top of all of this, i think i'm going to install a large extraction fan in the wall to vent the room to help with the fine dust that escapes at the tool.

Yep

- do you have any recommendations for filters? I've read up on Wynn filters, but cant find anything about them in Australia.

If you are venting outside you don't really need special filters but you do need some filtration but filter efficiency is not a priority issue.
The advantage of pleated filters is the large surface are so they have better flow and are slower to clog up.
Don't forget that once conditioned, most of the filtering done by basic filters is by the layer of fine dust that embeds itself in and over the filter. Filters like nano-filters or higher efficiency HEPAs will outperform the self filtration by the dust layer in a conditioned filter but these are only needed if the air is going to injected back into a shed.

In your experience, are higher power DC's much louder than 3HP? I'm already thinking about dampening the sound with an enclosure.

The bigger the impeller the noisier they usually are. Noise also has to do with the impeller vane design. Straight vaned are louder than backward carved vanes.

'The standard spring loaded toggle clamps around bags are rubbish.'

Could you elaborate on this? What do you use to seal the bags?

Originally Posted by Flintlock

'The standard spring loaded toggle clamps around bags are rubbish.'

Could you elaborate on this? What do you use to seal the bags?

My CT 3HP twin bag DC came standard with the following type of seal.



The greater the air pressure the more it presses the filter onto the (red) plastic hoop which in turn presses the other side of the filter hard against against the filter holder.
Unlike the spring loaded metal strap like clamps used by most DCs there is no "rucking" of the filter and I have never detected a leak around these types of seals.
However they do need to be made accurately to work properly.

Removing and inserting the red hoops requires the hoop to be slightly deformed. When it goes back into shape it fair "SNAPS" back in super snuggly.

I have the same DC as Bob's and agree that its far superior to the standard metal straps you get with some DC's. Its much easier to replace bags and there's no leakage. I also have a 2hp DC that uses the metal straps and its constantly leaking. The plastic hoops don't let anything through.

Heres what I typically see on the standard clamps of most DCs
The green circles show the rucks that allow the fine dust to escape as the clamps just down have enough pressure to fully flatten them.
This is the main reason to make sure the DC is vented or located outside a shed.
BSDC.jpg