Thread: Hafco DC3 Dust Extractor

Originally Posted by Damienol

Hi WWF

I Have a v small WW workshop and am desperate need for a dust extraction system after my shop vac gave up the ghost.
I have a 460x800x1900 space to fit a new system. Was think inking the DC3 however I can't find the dimensions anywhere. Can anyone help?

also keen to know what people think of it where to get cheap hose for it.

That DC is the same as this one. Carba-Tec® 2hp Economy Extractor : CARBA-TEC

It needs a volume of 560 x 850 x1950 mm so it looks like you will struggle to find the space to fit it straight out of the box
The limit is the drum diameter (480 mm) so you cant't really make this any smaller via modification.

H&F is about the cheapest retail hose I have seen.

Thanks Bob.

How certain are you that it is the same dimensions as the Carbatec version?

Just a little bit smaller and I will be cooking with gas

Originally Posted by Damienol

Thanks Bob.
How certain are you that it is the same dimensions as the Carbatec version?
Just a little bit smaller and I will be cooking with gas

Pretty certain - I looked at that 2HP model at H&F, the CT and the Timbecon (no longer on their website) about 4 years ago when I was buying a DC for the milling yard.
I ended up buying the Timbecon one even though it was a bit more because they were the only ones offering it with with a needlefelt bag as standard.

Here's a couple of suggestions.

Height wise you can remove the wheels and that should drop it to <1900
Is it just the floor space that has to be those dimensions?
If so you could just make a smaller base for it.

BTW that design with a curved piece of 5" flexy hose between the impeller and the bags is
a) inefficient because of the bent flex
and
b) limiting because you can't take advantage of using 6" ducting because the 5" flexy limits the flow rate of the impeller.
The 1200 fpm claims are for the impeller only ie no bags and no connection and as if you just use 4" or 100 mm ducting this limits extraction to ~400 cfm

A better design is one where there is no hose so the impeller is attached direct to the bags.
This Timbecon model Product Details
and
This one from Carbatech Carba-Tec® Industrial Twin Bag 2hp Dust Collector : CARBA-TEC
are examples of what I mean.
This one from Alltools
https://www.alltools.com.au/shop/ind...ctor_DC-60_2HP

This means you can then use 6" ducting and not have it throttled by the 5" flexy between the impeller and the bags and you should get 1000 fpm from such a system.

Thanks Bob

Think I have decided to put the unit in a different spot and then just move my other machines when I need to use them.

so now it is a toss up between the Carbatec and the Hafco. However you now have me a little worried I won't get enough suction

on a related note with the pipe I am wondering why I can't just use ag pipe from Bunnings for a quarter of the price?

Originally Posted by Damienol

Thanks Bob

Think I have decided to put the unit in a different spot and then just move my other machines when I need to use them.

so now it is a toss up between the Carbatec and the Hafco. However you now have me a little worried I won't get enough suction

on a related note with the pipe I am wondering why I can't just use ag pipe from Bunnings for a quarter of the price?

What type/size pipe are you referring, is it that black corrugated pipe?
Do you plan to duct or move the DC to the machine or some combo of that?

Originally Posted by BobL

What type/size pipe are you referring, is it that black corrugated pipe?
Do you plan to duct or move the DC to the machine or some combo of that?

Yeah the black corrugated pipe, $31 for 10 metres instead of $16 a metre.

Plan to move the duct. Will have it permanently connect to my table saw and move it a metre or so from the wall for big pieces. The other other hose will be connected mostly to my Dewalt thicknesser and then other machines as required. The Dewalt lives under my bench and I get it out as required.

The generally accepted spec for maintaining an adequate control over dust in a small workshop is 1000 cfm at 4000 fpm. Under this radar the DC might collect chips and leave your shed moderately clean but it simply cannot remove the invisible dust from the shed. Remember it's the fine dust that represents by far the most health risk.

Both those H&F and CT 2HP models are a 50 year old design. They claim 1200 CFM flow rates but there is no way these units can achieve this. This spec is for the impeller only.

The 5" flexy between the impeller and the bags restricts the flow to <900 CFM. Modification of the connection is very difficult because the ports in the impeller and the bag housings are fixed so 5" so major surgery is needed to open these up and in the case of the impeller it would almost be an impeller rebuild - ie not worth it.

These units also come with 2 x 4" inlets. The maximum that these 2 can provide is 800 cfm (each one does 400 cfm) however in practice it will be less than this because the junction used right in front of the impeller like that creates a lot of turbulence so it will be less than 800 cfm in practice.

The way around this is to ditch the 2 x 4" Y junction in favour of a single 6" duct so you can at least reach the flow limit of the 5" flexy (ie 900 cfm). Then connect any ducting a metre or so back from that.

Ideally you would then use 6" ducting and short connection of 6" flexy all the way to the machines but most machines use 4" ports which immediately limit (assuming no flow restriction by the ducting) flow to 400 cfm. If you use one metre of flexy it will be ~350 cfm, if you use the agricultural stuff it be less again. You can of course where possible use 2 x 4" ports.

Originally Posted by Damienol

Yeah the black corrugated pipe, $31 for 10 metres instead of $16 a metre.

That stuff is one of the worst things you can use on a low powered DC - losses are of the order of 15% compared to smooth walled flexy and smooth walled flexy looses ~12% over smooth walled PVC ducting. The use of flexy should be limited to the shortest possible lengths - just to connect pipe to a machine. The other thing about that corrugated pipe is that it makes a real racket when air passes through it.

Plan to move the duct. Will have it permanently connect to my table saw and move it a metre or so from the wall for big pieces. The other other hose will be connected mostly to my Dewalt thicknesser and then other machines as required. The Dewalt lives under my bench and I get it out as required.

It would be worth setting up smooth walled PVC ducting over head above the bench and connect with a short bit of flexy.
BTW H&F have 4" flexy at $13.20/m and you should only need a couple of m.

I can see you are trying what every tries and that is to solve what is in essence a $1000 problem with a few hundred. Unfortunately, there are no out of the box solutions for a few hundred dollars. Even the DIY methods require a fair bit of work, expense and ingenuity. To ensure 1000 cfm for a shed you really need a 3HP unit and to use 6" ducting and connections and be prepared to modify ports on machines to accept the 6" ducting.

There are alternative ways of dealing with the fine dust problem, like fitting a large roller door on one side of a shed and large windows on the other, but that would be more than a more powerful DC and the loss of wall space can be significant.

Wow Bob, you certainly know your stuff. Yours is the most comprehensive reply I have ever gotten on WWF. And you have given me plenty to think about. Thanks for all your effort

Hopefully I can pick your brain one more time. I have attached a photo of my workshop to help explain my setup.


So my current thinking is that I will put either the Hafco or the Carbatec 2Hp system in the far right corner - between the bandsaw and drill press (where the power board is hanging on the wall). This will mean that on occasion I will need to move these machines to work on larger pieces.

I am then thinking I will run one 4" PVC along the wall towards the Kinchrome tool chest in the opposite corner, attached some flexi to get the pipe around the corner and under the tool chest and then run another length of 4" along the ground all the way to the edge of my timber workbench. Off this pipe I will put a T connector in and run some flexi to the bottom of the table saw. With the far end I will put a bend in and run some PVC to the top back of my timber workbench where I will attach a 2 meter length of flexi. This connection will predominately be used for connecting to the 3" outlet (I will need a 4" to 3" step down) on my DeWalt Thicknesser.
I will need to find someway to limit the airflow to one of these machines at a time. (I think these might be call blast gates but not sure as I have never seen one)

With the other 4" outlet on the dust collector I think I will run some PVC pipe along the opposite grey wall and terminate it just above the lanisher. At the end of this I think I will connect some 3" flexi so I can move it from the lanisher to my drill press to my drop saw (which is just out of the picture). These systems produce little dust in comparrision so I think the 3" step down should be ok and it will not require me to make any changes to the Lanisher or drop saw.

I will need to find someway to limit the flow at the DC outlets so I can redirect flow to one pipe run at a time. Perhaps blast gates again. That would mean 4 blast gates in total.

In the picture you will see some existing grey flexi pipe connected to the roof. This is from my Kinchrome shopvac that blew up a couple of weeks ago an as a result started my latest round of research. The little shopvac did just enough for me to get buy. These proper DC's have over 10 times the suction of the shopvac so i am hoping these systems will be more then sufficient. I am trying to get it replace under warranty so fingers crossed. The plan will be to continue to use the shopvac for my small tools like my orbital sander and for general shop clean up.

Thoughts and guidance?

Originally Posted by Damienol

Wow Bob, you certainly know your stuff. Yours is the most comprehensive reply I have ever gotten on WWF. And you have given me plenty to think about. Thanks for all your effort

No worries. This thread should really be in the Dust forum. If you had followed some of the threads there you would already have worked out what was needed and what you propose is still a long way away from being much better than what you had. Have a look at threads by John Samuel about what he had to do to defeat the dust dragon.
Anyway, hopefully others that don't visit the dust forum can learn something from this thread.

As soon as a DC system is based on 4" ducting and bits of flexy for corners it's not a dust but a chip collector limited to operating around 300 cfm irrespective of what size DC it is attached to.

Anyway let's look at what you propose to see how it can be improved

Originally Posted by Damienol

I am then thinking I will run one 4" PVC along the wall towards the Kinchrome tool chest in the opposite corner, attached some flexi

Instead of Flexy for corners use 2 x 45º ducting connectors, if you do your research it will cost you less and work better than the flexy.

. . . . .to get the pipe around the corner and under the tool chest and then run another length of 4" along the ground all the way to the edge of my timber workbench. Off this pipe I will put a T connector . . .

Instead of a T use a WYE connector and a 45º bend to get the 90º on the leg of the T - they are much more efficient than a T.

. . . . in and run some flexi to the bottom of the table saw.

Use PVC duct and a 2 x 45º bend instead.

With the far end I will put a bend in and run some PVC to the top back of my timber workbench where I will attach a 2 meter length of flexi. This connection will predominately be used for connecting to the 3" outlet (I will need a 4" to 3" step down) on my DeWalt Thicknesser.

In this case using flex won't matter as the 3" Dewalt is seriously throttled anyway.

. . .I will need to find someway to limit the airflow to one of these machines at a time. (I think these might be call blast gates but not sure as I have never seen one)

Yes you will need blast gates.

With the other 4" outlet on the dust collector I think I will run some PVC pipe along the opposite grey wall and terminate it just above the lanisher. At the end of this I think I will connect some 3" flexi so I can move it from the lanisher to my drill press to my drop saw (which is just out of the picture). These systems produce little dust in comparrision so I think the 3" step down should be ok and it will not require me to make any changes to the Lanisher or drop saw.

When you say these systems produce little dust you mean " . . .little visible dust". The linisher and the Drop saw (and the thicknesser) are amongst THE worst machines for invisible dust. 3" ports are near useless at grabbing the fine dust generated by these machine so you will continue to have fine dust settling all over your workshop from these machines

In the picture you will see some existing grey flexi pipe connected to the roof. This is from my Kinchrome shopvac that blew up a couple of weeks ago an as a result started my latest round of research. The little shopvac did just enough for me to get buy. These proper DC's have over 10 times the suction of the shopvac so i am hoping these systems will be more then sufficient. I am trying to get it replace under warranty so fingers crossed. The plan will be to continue to use the shopvac for my small tools like my orbital sander and for general shop clean up.

Sorry but there is NO WAYl a 2 Hp DC connected to 3" ducting have 10 times the flow rate of a Kingchrome shop vac.
The Kingchrome will have about 100 cfm through a 2" duct - a 3" duct on a 2HP DC will have a MAX of about 200 cfm (less if you use flexy).
So your improvement in flow will be less than 2x. Remember you need 1000 cfm to collect fine dust at source so I predict significant disappointment in your proposed system - yes it will collect some chips but you will have more or less the same dust fall out over time as you have with the Kingchrome.

If you want the 10 fold improvement then EVERY pipe and junction and machine port in your shed MUST be 6" in diameter, or you need to use 3 independent 4" lines to every machine.

If you want to understand air flow in various size ducts/pipe you need to get your head around the diagram below.
The 3 purple arrows show the Max flow rate for the pressure generated by a 2HP DC (~10" of water) in a short length of different (3", 4" and 5") pipes.
As soon as you add bends, flexy, long runs of pipe, and collection bags get dirty its all down hill from there.

The DC by itself uses a 5" pipe so it is limited to 900 CFM (lime gree dot)
4" ducting is the orange dot ~450 cfm but flow rate drops more than 5" as greater length of pipe is used
3" ducting is the purple dot ~200 cfm and dropping faster than 4" with length
The Kinchrome VC operates at a higher pressure ~30" of Water pressure so using 2" duct it will deliver ~100cfm.

Damienol,

You are right ... BobL knows his stuff ... and his advice is spot on.

What are you trying to do? Is your aim to collect the chips; or is it to grab the great bulk of the very fine (invisible) dust that is the health hazard? No system can be described as good or bad until the aim is stated.

About seven or eight months ago I was wading through chips and dust and decided to do something about it. I thought a 2 HP dusty would easily do the job, but my reading of Bill Pentz's and BobL's stuff soon made me realise that this was not the case. I started by drawing up a wish list for my dust collection system. It is as follows:

1. I wanted a ducted system so I was not dragging machines around the workshop. That meant I needed a 6" or 8" ducted system.
2. I wanted to vent outside, so even the superfine dust was removed, and so I was protected against leaks.
3. I wanted a small footprint (so I could keep the system in the shop and did not need to build a shed outside for a dusty).
4. I wanted to achieve the magic numbers of 1000 and 4000 so I had a shot at capturing the very fine material and at avoiding clogged lines.

I managed to install a system that met all these requirements. It has now been weeks since I cleaned out my shop properly ... it does not get dirty. My biggest source of dust is over-spray when spraying sanding sealer and lacquer which are dry particles a couple of feet from the gun... and I have yet to fully tame my shop vac ... these things are notorious for producing lots of fine dust.

Your plan will likely remove the chips, if that is your objective, but the fine dust that is a health hazard will still be there. So, it is a good idea to start with the aim in mind.

The problem most woodies face is cost. Once you have read the research on dust collection, installing a 3 HP dusty or a 4 HP cyclone with 6" ducting are the glaringly obvious solutions, but they are more expensive than a 2 HP dusty.

When our budget limits us to a 2 HP dusty (it often does) then to do a good job we need to follow BOBL's advice. Get a machine with a 6" inlet (or one that can easily be modified to use a 6" inlet), use a short section of 6" flexy and move it to the WW machines as required (or move the WW machines to it). Finally, BobL makes a critical point when he says you need to modify the machine ports to take 6" ducts. A few ideas can be found here ... https://www.woodworkforums.com/f200/m...chines-161166/

In my case I did a dummy spit and wanted a complete solution that would see me off the planet, and so did SWMBO who was tired of my dust getting into the house. The cheapest solution that met all of my wish list was a Clear Vue cyclone. In fact it was the only solution that ticked all of the boxes on my wish list. It is a great unit that would suck start a whole fleet of Jumbo jets and it has a tiny footprint (about 700mm X 700mm). But it was more expensive than a 2 HP dusty.

Strongly recommend you start with a wish list. Cost your options and make a decision from there.

Originally Posted by John Samuel

.
.
I wanted to vent outside, so even the superfine dust was removed, and so I was protected against leaks..

.

To minimize the problem with leaks the pressurised side of the DC should be outside the shed, or inside a sealed cupboard vented to the outside. This means everything downstream of and including the impeller. A vented cupboard can be a possible leak but with a big enough DC it is possible to negatively pressure the cupboard so that it leaks inwards rather than outwards.

Seals or joins that are more or less or permanently connected are less susceptible to leaks, joints that need regular opening like collection bags or bins are the ones to watch. Most of the systems I have measured have clearly visible leaks the worst being around the collection bags.

Originally Posted by BobL

To minimize the problem with leaks the pressurised side of the DC should be outside the shed, or inside a sealed cupboard vented to the outside. This means everything downstream of and including the impeller. A vented cupboard can be a possible leak but with a big enough DC it is possible to negatively pressure the cupboard so that it leaks inwards rather than outwards.

Seals or joins that are more or less or permanently connected are less susceptible to leaks, joints that need regular opening like collection bags or bins are the ones to watch. Most of the systems I have measured have clearly visible leaks the worst being around the collection bags.

Again, good advice.

I chose a cyclone and not a dusty for several reasons. One is that with a cyclone we would need to screw up badly to have any leaks. It is an inherently robust system. Cyclones do not use bags, and in Australia we don't even need filters, so there is very little to go wrong.

Originally Posted by John Samuel

Again, good advice.

I chose a cyclone and not a dusty for several reasons. One is that with a cyclone we would need to screw up badly to have any leaks. It is an inherently robust system. Cyclones do not use bags, . . . ..

sure but they still use a bin or a collection box to hold the sawdust so the seal around that is a potential source of leaks.

Originally Posted by BobL

sure but they still use a bin or a collection box to hold the sawdust so the seal around that is a potential source of leaks.

Bob,

That is true. The instructions that come with the cyclone call for a foam seal on the bin lid, which I have installed. However, the bin is under a bit of negative pressure. When I turn on the cyclone and the bin is empty or quite low, it gets lifted off the floor by about 20 mm, suggesting leaks here are not an issue. The only time we need to be careful is when emptying the bin. I generally empty mine when it is less than 3/4 full.

By my reckoning, the only place where leaks are likely is where the HVAC duct (exhaust) is taped onto the plastic exhaust transition. So, I check it occasionally. So far, so good.

It seems that an equally significant issue in this case is space. Can a 2HP dusty be squeezed in to that shop? If possible, I'd be looking to put the dusty outside, and that would also protect against leaks.