Thread: replacement hose for dust extractor

purple pig they do all types of hoses Valves, Hoses & Couplings

maybe try Eximo no idea on price tho they have different plastic types so I would suggest an enquiry on the best type


pete

thanks fubar and pjt i will give them a call next monday, thanks for all of your help it is appreciated. regards peter flack

No worries Peter, I'd be interested to know what Eximo say and how much the 125mm hose is, the downside is they might want to sell you a 10m roll, if that is the case and price is OK maybe if enuff others want some 125 as well might be worth getting a roll, I also need a bit of hose same size.


Pete

PS
and what else you find out from other suppliers

I too baulked at the price for vacuum hose. I bought 10 metres of 100mm flexible ribbed subterranean storm water pipe from the big chain hardware shop for $29. I cut a slot in some "found" 105mm PVC pipe and pop riveted the pipes together to make an adaptor to fit my machines and used normal clamps to secure the ends. Works well and is quite flexible enough to convert my jointer to a thicknesser without disconnecting the dust system. I have about 7 metres of pipe left for next time or my next machine. Much cheaper than the bought stuff.

I've been considering replacing all the ribbed flexible lines on my dust extraction unit with clear flexing plastic piping as all those little ribs must reduce the effectivenes of the system. I just need to get off me rear end and suss out what is avaliable... one day.

Cheers
Rod

Originally Posted by rod1949

I've been considering replacing all the ribbed flexible lines on my dust extraction unit with clear flexing plastic piping as all those little ribs must reduce the effectivenes of the system. I just need to get off me rear end and suss out what is avaliable... one day.

Cheers
Rod

The ribbed stuff works moderately well, on 1 HP units as the air speed is already slow so it is not affected much but on 2 and 3 HP DCs ribbed hosing knocks the stuffing out of their air speed. In practice even smooth walled 100 mm ducting should not be used on 2 and 3 HP.

In practice even smooth walled 100 mm ducting should not be used on 2 and 3 HP.

Interesting, what should be used, please BobL?

Originally Posted by BobL

The ribbed stuff works moderately well, on 1 HP units as the air speed is already slow so it is not affected much but on 2 and 3 HP DCs ribbed hosing knocks the stuffing out of their air speed. In practice even smooth walled 100 mm ducting should not be used on 2 and 3 HP.

I'm not sure what options remain for my system. I have a 2 HP dust extractor and it has 100mm fittings and so does my equipment. I have excellent flow and effective dust collection with ribbed 100mm pipe. I have not measured air flow but I would not expect the ribs which are outside the 100mm to have too great an effect on overall flow/resistance/pressure gradient etc. After-all the internal diameter is the same as a smooth 100mm pipe and a boundary layer associated with the ribs might actually reduce friction. It inspires interesting experiments, but life is too short.

Originally Posted by JillB

Interesting, what should be used, please BobL?

Paraphrased From Bill Pentz Site;

Ducting resistance is known as static pressure. Even a short run of duct that is too small for a blower will cut the airflow down to the highest speed that pipe can sustain. The impact on most hobbyist blowers is terrible. On 4" ducting a 1 HP unit that rated at 650 CFM maximum rarely will maintain 350 CFM. And a 2 HP capable of 1200 CFM is lucky to provide 500 CFM. Bumping up to 5" pipe adds about 100 CFM to each of these configurations. Bumping up to 6" the bigger units end up going to 800 and 900 CFM. As a result, you need to use at least 5" duct for any hobbyist blower rated up to 1100 CFM and 6" or larger duct for blowers rated 1100 CFM to 1800 CFM

NB this has nothing to do with bag resistance - it's just what different size pipes and "reasonable" junctions do to air flow. Adding clogged bags makes things even worse.

and there is more;

Unlike big industrial sites, most hobbyists should run the same sized ducting, fittings and hose right up to their machines. Don't do like many and run a 6" or 8" main trunk line then come off with single line smaller duct or flex hose. The smaller pipe will kill the airflow needed to keep the air in the mains moving fast enough to avoid plugging and building up dust piles. You have to keep three 3" ports open at once or two 4" ports to avoid the plugging a 6" main and even more open for larger mains. Having so much open often kills the airflow needed to collect the fine dust. If you use standard hoods you should still convert over to 6" ports. Even reducing ducting size right at the machine for the shortest possible distance to a small 4" port will still kill system performance.

Originally Posted by Fred Nerk

I'm not sure what options remain for my system. I have a 2 HP dust extractor and it has 100mm fittings and so does my equipment. I have excellent flow and effective dust collection with ribbed 100mm pipe. I have not measured air flow but I would not expect the ribs which are outside the 100mm to have too great an effect on overall flow/resistance/pressure gradient etc. After-all the internal diameter is the same as a smooth 100mm pipe and a boundary layer associated with the ribs might actually reduce friction. It inspires interesting experiments, but life is too short.

Unfortunately this is a misconception since these ribs are not smooth and will set up significant turbulence that penetrates well into the passing air stream and impacts the flow rate. The more fluid that is pushed through rough pipes the worse the flow rate gets. There is a big difference on the effect of turbulence between moving a compressed fluid inside a pipe and pushing a solid object through an uncompressed fluid. For this and all sorts of other reasons hydraulic engineers will do anything to minimize turbulence inside pipes.

Only the other day I was watching a simulation of a fluid moving under pressure through a pipe with a small dent on the surface of the inside wall. As the fluid pressure increased the flow increased and the dint started generating turbulence so that eventually the fluid flow was clearly no longer increasing in proportion to the increase in pressure.

Ironically scientists have discovered a way to reduce turbulence by injecting intermittent puffs of turbulence along the pipe but it's still best to not to have the turbulence to begin with.

hi every body, many thanks for all the replys to my post and i apolagise for not replying to them all this is the first time since the 1st sept i have been on have been extremely busy and computer was giving me a hard time also. i will get time to look at the possibility of using 5inch pvc pipe incorporating a 45degree bend but will have to see if it works out cheaper i just hate getting ripped off and i feel the prices wanted was just that, carba-tech even went as far to inform me they were the only ones who sold it and basically the best of luck getting the pipe elswhere. where there is a will there is a way. i am very good at improvising and adapting and of course you only have to ask like i did here on this forum and there is nothing i believe you can not get an answer for or a solution to a problem. kind regards and again thanks (grandad) peter

PVC could be a bit dangerous because of static charge build up. You should make sure you use an antistatic hose. call Eximo on 1300 number and mention the forum. They sell in per metre lengths.

Originally Posted by BigMel

PVC could be a bit dangerous because of static charge build up. You should make sure you use an antistatic hose. call Eximo on 1300 number and mention the forum. They sell in per metre lengths.

I see this is your first post so I will go gentle on you.

This has been discussed many time on this and other forums.

One of the best is this.
PVC