Cyclones - local a/c ducting company hopes to make me one

[Anonymous]

Hi all

New to these forums but here goes.

I have been in discussions with a local sheet metal working for building a Bill Pentz Cyclone. Initally the cost was to be £800 but it has slowly come down from there - and I am still working on it. Initally he thought that constucting the air ramp would be very expensive as to do it properly would take a long time as it would be made up of about 60 triangles to get the proper fit.

I am interested in anyone who wants one built - if I go to this chap with an order of say 5 I am sure I will get a much better price than one.

My idea is to build an 18 in/ 400mm size as this fits into my w/shop.

Any feedback welcome
Francis

 

[DaveL]

Hi Francs,

Welcome to the forum.

For me you are a year too late, :evil: take a look here.
I hope you can get the price down as £800 is a lot of money. I don't see why he is using lots of triangles for the air ramp, I would have thought a circle, cut and flanged should do the job. It could even be fitted with a number of small tags and the side seam sealed with filler.

 

[engineer one]

try to remind him that always KISS is better
keep it simple stupid.

the outside of the cyclone could be made by a metal spinner i am
sure, thenthe ramps should be easy ha ha :evil:

paul :wink:

 

[Noel]

Hi Francis, welcome to the site. £800 sounds waaay too much. No disrespect to you or your fabrication company but raw materials shouldn't come to more than £50 or £60 max.
As Dave says what's with all the triangles? There plenty of sites accross the web that will show exactly what is involved. BTW does the £800 include the impellor and the motor? Most people have or buy a cheapish chip collector and go from there.
For £800 you could ship a manufactured unit ready to go from the States.
As I mentioned, no disrepect intended and please let us know how you get on.

Rgds

Noel

 

[engineer one]

ok lets get controversial, both dave l and barry have made decent
cyclonic systems over the last couple of years, and shown us.
but i wonder in view of the space considerations whether the
cyclone is the way to go.

you need to do two things really, allow the heavy stuff to drop out
as quickly as possible, and try and stop as much dust as possible
before it gets to the filter and or motor.

in principal the cyclone relies upon the air agitation being too weak to
carry the heavy bits too far along the system.

but air flow is capable of doing this without the cyclone. i think.

at the risk of activating an old argument, racing cars use air flow
in similar ways to those we need to address, and because of their
movement, do not use cyclonic items rather they use wings and splitters
and the bernoulli effect.

so i wonder why we are not pursuing the path of using flat planes
and the differences in air pressure due to inlet and aperture size
rather than the horrendously long cyclonic activity.
i have been thinking about this for some months since i first saw
some of barry's ideas, but not yet put it into practice, have to consider
the maths.

as stated elsewhere, i am sorting the dust collection under my
dewalt 744 and will try to experiment there.

have built a smallish wooden box which encloses the blade,
and keeps the motor outside. next when i put it on the stand,
there will be a hole in the mounting plate, and initially i am
just going to put a plastic bag there, and see what happens.

with a table or cabinet saw you have a different set of problems
than with other tools since you have with dx 3 kinds of air flow.
1/ the blade agitates the air.
2/ top extraction is generally through a smallish diameter pipe
3/ lower extraction is through a big pipe.

there is a point underneath where there is turbulent air, but
also there will also be an area of still air. question is where are
they both, and how can you use it.

my idea is to try and have the air flow in a flat way across and
over and under a number of cloth filters, but who knows how far
this tuit will take me? :twisted:

anyone else looked at an alternative to cyclone? :?

paul :wink:

 

[Barry Burgess]

Francis
I am just down the road from you in Camberley and you can come over and see my cheapie cyclone and possible build another one.
I started out looking for a sheet metal shop to build one. First off I was quoted £250+VAT and I gave the go ahead. After 4 months of excuses and an attempt at making it, I gave up with them. A long struggle in sued, visiting some 15 places to get it done. The highest price quoted was £1100 +VAT in stainless steel. Most would not quote. The ducting people are the best as they do most of this kind of work. They all have trouble with the Pentz spreadsheet.
If you are using the 18" diameter I would use at least a 3HP motor and also consider a 5HP.
My approach was to decrease the diameter to 14" and use a 3HP motor that has worked out very well.
My costs were as follows
Ikeas flower pot £22
Recycled 65 litre drum £7
Say 1 sheet MDF £14
Piping (mainly scrap) say £10
Total build time about 8 10 hours
My metal work skills are zero - prefer working with wood

The filters cost me £122
The dust extractor cost £135 delivery from E bay
The silencer/baffle cost £20
The clear 6" flexable hose £40

As to the air ramp it goes from the top of the retangular inlet pipe to the bottom and can be fixed with a rivet to bottom and glued to the outside end in the drum. All the shops I visited sited that as lots of work yet it is simple to do.
PM if you want any other help
Barry

 

[RogerS]

Barry et al

Have you come across any of the UK academic papers published on cyclone dust extraction and other information such as this?

 

[Newbie_Neil]

Hi Francis

Welcome to the forum.

Cheers
Neil

 

[Newbie_Neil]

Hi Paul

ok lets get controversial ...... but i wonder in view of the space considerations whether the cyclone is the way to go?

Thank you for a really interesting post.

Cheers
Neil

 

[Barry Burgess]

Roger
I remember reading this paper and some others but the arguments put forward on the Pentz's site was more compelling.
Changing the dust collection at each machine to improve the flow is just as important as the cyclone itself. I have made new 4" collection points for my table saw, router above the table and am completing the new router table for collection below the table. This will remove one of the biggest dust problem(collection) I have and I will finally have to come up with a better collection method for my mitre saw.
I also feel that a cyclone without any filters defeats the object of the collection.

 

[Barry Burgess]

ok lets get controversial, both dave l and barry have made decent
cyclonic systems over the last couple of years, and shown us.
but i wonder in view of the space considerations whether the
cyclone is the way to go.paul :wink:

Paul having made 2 mini cyclones and about 4 different dust bucket and just one large cyclone, I am game to give anything a try but we have to get a lot more specific. I am all for thinking outside the box (Edward D or Tom P) but I have found nothing during my search to lead me in another direction. I use MDF as my bench mark as I do not own a thicknesser for testing.
I don't think that a 2' by2' floor foot print is large for any workshop although with a low ceiling height it presents a few more problems.

 

[Barry Burgess]

Francis
Another option you could consider is getting CCL to make the main body out of 450mm diameter and the cone with a 150mm outlet. I got a quote of £139 including VAT using the Pentz's dimensions and I don't get trade prices.
At £800 it would be cheaper to import the perspex Clearvue cyclone with impellor from the USA and get ta motor locally
Barry

 

[engineer one]

barry,i know from our talks you are happy to look outside the box,
and i agree that much of your system footprint is ok, but the height issue would affect me which is why i am thinking another way.

roger that file takes for ever to save, so will print it out , and then read and report . :lol:

paul :wink:

 

[Barry Burgess]

Paul if you reduced the diameter to 10" say the cyclone height would be 31" and use 4" pipe and a 1 or 2HP motor. This would allow the dust collector bin to be of a reasonable height - side mount or top mount the motor.
Barry
ps gravity alone will not work with MDF dust

 

[engineer one]

barry now you tell me about the gravity!!!!!!!!!

my consideration is that we have two separate needs when using dx,

1/ table saw, routers, band saws, maybe circular saws, pt's are all
likely to produce more than just dust.

2/ sanders and biscuit and dowel joiners and the new domino all make
dust.

so maybe we can look for different things or parts for each tool.
so all i was wondering is whether cyclone is overkill for most of the time?

i can see with the photos of your system barry that you could have
an addition to use when making dust rather than chips, but for those
with say the 6ft 4 high shed of another poster wanting to re-design his
workshop then 2x2 feet is a lot of volume to lose. in his case he might be better off having the cyclone outside, but.

anyway off to read the papers roger suggested, and then i will see how much further i can go.

paul :wink:
whose throat has tightened up again making the dx equipment :?

 

[Anonymous]

If you read Petz's site he mentions anything less than 6in duct is just no good - if you have 6 inch duct you will then need 18inch cyclone (about 3 x duct diam) otherwise you there is no point in having 6 inch duct

Francis

 

[Barry Burgess]

Paul they could use the mini 'cyclone' with a vacuum cleaner like this

Its simple to make

And you fit a funnel from a brewing shop like this

 

[Barry Burgess]

If you read Petz's site he mentions anything less than 6in duct is just no good - if you have 6 inch duct you will then need 18inch cyclone (about 3 x duct diam) otherwise you there is no point in having 6 inch ductFrancis

Your 1.5HP motor will need very short hose to run 6" pipe if it works at all. Even with 4" your runs will have to be short.
Bill's 5HP motor and impellor cost too much for me and 6" piping would have to be metal AC tubing.
Barry

 

[engineer one]

barry, interesting, but as you are aware under the saw i will only
have 500mm, so must look for alternatives, not sure i want it lengthways.

my mates at jaycee can get plastic re-inforced extractor tubing at about
16 quid a metre in 6in dia, not sure whether that is cheap or not.

anyway looking around ikea,i noticed a vegetable drainer which will expand to fit a gap, think this will be my stage one filter for the saw, since it will allow dust through, but keep out bigger stuff, and be removeable.
and for a fiver it is worth trying i think. otherwise i was looking at
chicken wire.

so you can tell i am looking for a down and dirty solution, not necessarily the rolls royce version since most of it will be hidden. :twisted:

paul :wink:

 

[Pecker]

Firstly a note to the mods. Since extraction seems to be a constant and popular subject over the years, why not have a section just to discuss it /them?

Ok, I have a 500 sqft workshop (approx 16ft wide, 33 ft deep). I have a p/t, circ saw, radial arm and other hand held bits.
I want the extractor outside which will put it approx 25 - 30 ft away from the machines.

How does one work out what size motor, pipe and airflow I need to work well?

Mark