Thread: pvc pipe size for ducting

Originally Posted by rellik

hey guys...i have a carbatec 2hp economy dust extractor and i want to run pvc piping with blast gates on each machine instead of connecting it to each machine as i use them.....just wondering...most of my machines have 4 inch outlets and was thinking of using as close to this size pvc piping throughout my shed....would this be ok or should i run bigger/smaller diameter piping instead??....any help you can give will be great
cheers

Hi Rellik,

DO NOT go any smaller than 4". It will choke the dusty. It is probably choked enough already using 4".

I have a 2hp dusty with a 5' inlet. I am looking to (as soon as I can get some meaningful shed time) expand the intake to 6" and run 6" pipe to my machines. I do not use blast gates. All my equipment is on mobile bases and I wheel them to the middle of the shed and plug the dust extractor hose into them. It takes a couple of seconds to move the intake from one machine to another the way I have it set up. Currently it is all 4". But blast gates is good if you have the space to set everything up as a static workstation but that usually means long runs of pipe and subsequent loss of suction.

Doug

thanx for the help....ill have a look at my shed and figure out what i wanna do ...either run ducting or run one long pipe and connect it to eachmachine as i use it...

rellik, I have just finished doing the same in my shed. I have a 2hp DE from Hare and Forbes. I have used 90mm pvc for all of my ducting. Where the pvc joins into the blast gates I used silicon and small screws to keep the joint stable. I also used 100mm flex pipe to join some sections.

One thing I also did was install an outlet that goes all the way to the floor which will allow me to sweep up my shavings and send them straight into the DE. In total I have 6 outlets connected into my system. Photo's to follow if you like.

Kev

ohh nice...yeah deffinately photos.....how to you find the suction on it???....also how many metres of ducting did you use approx.....

rellik,

There is an optimum size of duct for any given airflow/size of dusty. Too small and you restrict flow. Too large and your velocity drops and you might get material falling out of suspension. Apart from duct size and fittings etc, machine ports are mission critical (see https://www.woodworkforums.com/f200/m...chines-161166/)

To work out the optimum you need to know how much air your dusty pulls, but BobL probably has a pretty good idea what would suit your machine. If he does not reply here, you might like to drop him a PM.

If you are keen, a look at Bill Pentz's material is worthwhile. Bill's Cyclone & Dust Collection Research - Ducting

Cheerio!

If you are going to use 100mm pipe you might find the link useful.

https://www.woodworkforums.com/f11/co...27/#post264883

Regards,
Bob

A naked carbatech 2HP DC should be able to pull 1000 cfm with the 4" Y adapter removed and a clean filter/bag. As soon as the 4" Y adapter is added the flow reduces to ~800 cfm as 4" ducting at normal DC pressures can at most pull 400 cfm thru a 4" orifice. A 90 mm orifice is limited to about 345 cfm. When long lengths of ducting and flex is added it all goes downhill from there.

If you want the ability to retain the full 1000 cfm capability of the DC (particularly up to say a TS) then some mods are required to the DC inlet so that 6" ducting can be fitted and as a trunk line around the shed. Where possible at each machine connect with a 6" inlet or if this is not possible use 2 x4" inlets (ie get at least ~800 cfm). If a machine has only one 4" inlet then use that but when you have finished open up at least another 1 or 2 inlets and leave the DC running so that it clears the shed of fine dust.

This approach may not do all that much visually for chip collection but it will be at least twice as good for invisible dust removal.

I'm with BobL and others above......I ended up removing the 4" Y junction on the DC and fitted 6" ducting to it. Dust collection is a long term solution so I decided to invest in proper metal ducting with blast gates. Most of the ducting is smooth metal ducting with minimal use of flexible ducting only because had to. I have 6" trunking right up to the equipment and reduce to 4" when required and only because too lazy to make up new 6" ports. Anyhow it seems to work nicely. As my DC is 2hp I have plenty of blast gates so that I concentrate on one machine at a time. One day ill get a cyclone

Originally Posted by simops

I'm with BobL and others above......I ended up removing the 4" Y junction on the DC and fitted 6" ducting to it. Dust collection is a long term solution so I decided to invest in proper metal ducting with blast gates. Most of the ducting is smooth metal ducting with minimal use of flexible ducting only because had to. I have 6" trunking right up to the equipment and reduce to 4" when required and only because too lazy to make up new 6" ports. Anyhow it seems to work nicely. As my DC is 2hp I have plenty of blast gates so that I concentrate on one machine at a time. One day ill get a cyclone

Hi Simops, Where did you get yor metal ducting from ? I'm in the pocess of setting up the ducting in my new shed and am considering metal ducting as some of the bends I want don't seem to be available in 6" PVC.

Bruce T.

Bruce.....I got mine from Ezi-duct (google it for address). It's not cheap though....metal ducting is expensive compared to PVC but I figured that it is a long term investment and as I'm happy with my shop layout if I moved I would take it with me and set it up again. The metal ducting has fittings that allow it to be easily dismantled and re-moved.

cheers

mike

Originally Posted by simops

I'm with BobL and others above......I ended up removing the 4" Y junction on the DC and fitted 6" ducting to it.

Well done!

With overhead ducting I reckon it would pay to modify these DCs so the impeller was directly connected to the filter/bag housing with the impeller inlet located at the top so that ducting could come straight down into the impeller. This would reduce the tangle of ducting at floor level associated with these DCs.

Bob.....agreed.......I'm also considering using metal ducting with sweeping bends of course to replace some of the flexible ducting from the trunk duct to DC to reduce further friction from the flex spiral tubing....one day!

Would a cyclone type DC solve some of the issues you mention?

cheers

Originally Posted by simops

Bob.....agreed.......I'm also considering using metal ducting with sweeping bends of course to replace some of the flexible ducting from the trunk duct to DC to reduce further friction from the flex spiral tubing....one day!

Would a cyclone type DC solve some of the issues you mention?

cheers

If you mean being more suited for overhead ducting then yes.

I'm in the process of throwing out a convoluted network of 4" flex duct and blast gates, to be replaced with a single 5"/6" flex hose (~2m). This will be reduced down to 4" for the last section to allow plugging onto machine dustports. I've already rearranged the shed so that the dusty is at the centre of the machines it needs to be used with. Dusty is a Carbatec 2hp unit, and I've already replaced the standard needlefelt filter with a pleated filter cartridge.

A couple of questions for those who have already gone down this road

(1) Does it make much difference going with 5" flex hose attached to the dusty, or 6" via an adaptor? This thread seems to indicate 6" is better - does anyone have any pics of their adaptor to connect this to the dusty? Also, apart from Felder, can anyone suggest good sources of flexible 5" or 6" ducting?

(2) Does it make much difference what length of 4" flex hose is attached at the end of the 5"/6" hose? I was going to use about 1m of the ultra flexible translucent 4" hose that I already have, but is there any benefit in making this section REALLY short (as in 30cm or so)?

Any advice much appreciated !

Cheers