Thread: CV - 1800 vs Max

There are more knowledgable people than me on the forum but my take on it was that my workshop is fairly small at 3.7 x 5.8 so the duct runs are quite short. Therefor, the losses should not be great. It is unlikely that I will ever have a larger workshop so no need for a Max. This is the sort of thinking needed to firm up a decision. My CV is definitely quieter when running at 50hz so I would think that the Max at 50hz would not be much, if any, noisier because most of the noise is on the exhaust side which I and others have found can be muffled down quite effectively.

A good feature of the Max is that it possible to run a 6" pipe to the saw cabinet and a 4" to an overhead guard AND also have a 6" overhead open pipe scrubbing the air at the same time.

safari,

thanks for your thoughts and reasoning. My new shed is 9 x 6m and I plan to have the CV in one corner so I could end up with reasonable size runs but plan to keep my most used (and dirtiest) tools as close as I can.

cheers

Mick

Hi Mick,

Given the size of your workshop and John's idea that he should have bought the Max I think it would be worth an extra $300 in your case. I am very happy with the 1800 in my situation when I compare the performance with other types of DE's I have seen in operation.

Good luck with your decision making.

David

Originally Posted by mick59wests

Setup
- The Max has a 200mm inlet and outlet so there is some 'mucking about' to get it to attach to a single 225mm or two 150mm PVC pipes
- The 1800 inlet and outlet from the cyclone are 150mm so (as best as I understand it) this basically means standard 150mm PVC will fit directly onto these

As I understand matters, both have 8" outlets.

Originally Posted by mick59wests

Sucking Power
- The Max is rated at 1935 cfm compared to 1442 for the 1800. This (probably of course) is the main reason I favour the Max. It allows me to lose more static pressure and still get 1000cfm. If I am only running 150mm ducting I should therefore always be able to get 4000fpm as well. The Max also gives me some options with my lathe where I could run a single 225mm PVC to it (which I think would be the best, but more expensive option) or 2 x 150mm PVCs or just leave a single 150mm ducting which will be sucking harder

There is nothing wrong with an 1800, but the Max does a better job of future proofing your system (running two machines at once). It also gives you the option to leave a 6" port open to scrub the air. However, I reckon the bigger benefit is the ability to run either an 8" or two 6" lines to a particularly difficult machine ... like a lathe ... but I have no expertise here.

It really is a personal decision. If you go for the 1800, you are buying a very good system. The Max is bigger, badder and better, but are you willing to pay the additional loot for the machine and the ducting?

Over to you, Red Leader.

John,

thanks for the input. For me, a day or two more of navel contemplation / crystal ball gazing / seeing if I get some further feedback and another chat to shedman and I will be ready to decide.

cheers

Mick

Hi Mick,
I am also tossing up between the CV1800 and the max, I was looking at the Corrimal Men's Shed site and at their CV max install and saw that they were using 9" storm water pipe for the main line instead of 8" sewer pipe. This might be a cheaper option but I don't know if running the max at 50 Hz to keep the noise down would have enough air moving through it to keep the 9" pipe clean. Some one else might be able to answer that.

Bazza

Bazza,

thanks for the reply. After looking at the cost even of 225mm sewer piping and all of the bends, etc (a previous post, not so far back), my first cut got me to near $2k in ducting. However, I also believe to run through 9" it would need to run at 60hz.

My thinking now is to run 150mm sewer pipe everywhere and run it at 50hz in general if I go for the Max.

For my lathe, I would either run a second 150mm that I will open up and run at 60hz while sanding. In general, it seems it would be better to run a single 225mm to the lathe but then I expect I would always need to run at 60hz to get the 4000fpm airflow with the accompanying noise and power consumption.

I know I'd also be interested in other opinions.....

cheers

Mick

Originally Posted by mick59wests

. . . After looking at the cost even of 225mm sewer piping and all of the bends, etc (a previous post, not so far back), my first cut got me to near $2k in ducting. However, I also believe to run through 9" it would need to run at 60hz.

It's not necessary to run the 225 mm ducting to everywhere in the shed to benefit from the large Max Inlet. All that is needed is to connect ~1.5m or so of 225 mm to the max and install a 225 mm Y junction onto the other end of the 225 mm ducting.
Install 225=>150mm reducers on the ends of the Y and duct one of these to the rest of the shed and leave a blast gate on the other ( I'll call this BG1).
You can then leave BG1 open all the time to scavenge any escaped dust from the shed or close it to direct a greater press to the other duct.

Originally Posted by BobL

It's not necessary to run the 225 mm ducting to everywhere in the shed to benefit from the large Max Inlet. All that is needed is to connect ~1.5m or so of 225 mm to the max and install a 225 mm Y junction onto the other end of the 225 mm ducting.
Install 225=>150mm reducers on the ends of the Y and duct one of these to the rest of the shed and leave a blast gate on the other ( I'll call this BG1).
You can then leave BG1 open all the time to scavenge any escaped dust from the shed or close it to direct a greater press to the other duct.

Bob,

thanks for above. I have seen the posts about getting a reasonable size straight length directly from the inlet to avoid turbulence. Also, I have seen write ups on having a second port open to scrub the air for the Max but this generally seems overkill to me as I should be putting more effort into capturing at source. My main concern is whether I can only have a single blast gate open and run at 50hz (or somewhat less than 60) to reduce noise and even power consumption. My question (and I am not sure if anyone knows the answer) is having the 1.5m of 225mm ducting and then only running 150mm after that going to allow me to run the Max at 50hz (or what would be the minimum I need to run it at) to still get the 4000fpm through the 225mm ducting?

Perhaps I should go for the 1800 but I do like the additional options the Max offers.

thanks

Mick

Originally Posted by mick59wests

My question (and I am not sure if anyone knows the answer) is having the 1.5m of 225mm ducting and then only running 150mm after that going to allow me to run the Max at 50hz (or what would be the minimum I need to run it at) to still get the 4000fpm through the 225mm ducting?

That's another reason to have the second 150 mm connection to the 225.

The 4000 fpm is not a black and white figure but more of a guide and problems arise when the airspeed always stays below that speed.

At 1935 cfm using 225 mm ducting will have an air speed of ~4400 fpm. If you close the second of of the 2 x 150 mm ports only about 1250 cfm will flow through the system since that is the limit of 150 mm ducting.
This means the air speed is the 225 mm section will now be 2800 fpm which is not good but if the other port is then opened up the air speed in the 225mm section will go back up over 4000 fpm and should pick up any dust that may have settled out. The first metre or so of the 225 mm duct is unlikely to cause a problem because there will always be some back turbulence from the impeller.

To reduce the problem and save $ you could always replace the 225mm duct with a wooden 8" square duct that is about 1.5m long and glue two 150 mm connectors, one straight through and one at an angle directly into the square duct.

Originally Posted by mick59wests

My question (and I am not sure if anyone knows the answer) is having the 1.5m of 225mm ducting and then only running 150mm after that going to allow me to run the Max at 50hz (or what would be the minimum I need to run it at) to still get the 4000fpm through the 225mm ducting?

Further to Bob's comment ... if you want to run the Max at 50 Hz to keep noise down, you will get the CFM and velocity you want at the machine provided only one 6 inch duct is open; but as Bob says, you won't get good velocity in the 225 mm length of pipe. Bob's figures are for a Max running at 60 Hz.

If you are primarily concerned about noise, get a Max and run it at 50 Hz ... that will give you the same airflow as an 1800 running at 60 Hz (both with 6 inch ducts).

If you want really good airflow (see post here for some real data https://www.woodworkforums.com/f200/m...6/#post1723892) get a Max and run it at 60 Hz with 225 mm duct as Bob described.

If you want to get both the high airflow of a Max with minimum noise (running a Max at 50 Hz sometimes and at 60 Hz when you really need the extra airflow), make sure the 225 duct has an inspection port or similar so you can clear it if it blocks.

Why not get a Max, rig it with 6 inch pipe everywhere and run it at 50 Hz? If later on you decide you want to be able to run two machines/ports simultaneously, it would be neither difficult nor expensive to drop in a short length of 225 mm pipe with an inspection opening.

EDIT: Another option would be to do a first-class soundproofing job on the cyclone (perhaps combine two layers of HVAC insulated duct for the exhaust with a soundproofed cupboard) and to always run it at 60 Hz.

Originally Posted by BobL

That's another reason to have the second 150 mm connection to the 225.

The 4000 fpm is not a black and white figure but more of a guide and problems arise when the airspeed always stays below that speed.

At 1935 cfm using 225 mm ducting will have an air speed of ~4400 fpm. If you close the second of of the 2 x 150 mm ports only about 1250 cfm will flow through the system since that is the limit of 150 mm ducting.
This means the air speed is the 225 mm section will now be 2800 fpm which is not good but if the other port is then opened up the air speed in the 225mm section will go back up over 4000 fpm and should pick up any dust that may have settled out. The first metre or so of the 225 mm duct is unlikely to cause a problem because there will always be some back turbulence from the impeller.

To reduce the problem and save $ you could always replace the 225mm duct with a wooden 8" square duct that is about 1.5m long and glue two 150 mm connectors, one straight through and one at an angle directly into the square duct.

BobL,

as always (and this time especially so ) very much appreciated. This is exactly what I was looking for - and also what I suspected in regards to fpm which is why everything says to keep 2 x 150mm ducts open. I also like your 8" square ducting idea. What has taken me a 'little' while to understand is that even having two x 150mm ducts open at the same time, they basically need to be in the same 'zone' (really connected to the same bit of 225mm PVC) to ensure you get enough fpm through the whole length - just another part of the learning curve....

It also sounds like if I ran with one gate open most of the time but opened the second one 'for a while' at the end of a 'session' I should pickup any settled fine dust. Of course if I was turning green wood I would expect this could more easily stick. Does this sound right?

I also like your idea of making my own 8" square duct - even I should be able to manage that one . Being square, I expect I should double the area of a 150mm round pipe so it would be better to be a little less than 200mm (closer to 188mm for a 150mm internal round diameter) if I am understanding principles.

cheers

Mick

Originally Posted by John Samuel

If you want to get both the high airflow of a Max with minimum noise (running a Max at 50 Hz sometimes and at 60 Hz when you really need the extra airflow), make sure the 225 duct has an inspection port or similar so you can clear it if it blocks.

John,

some great things for me to think about. Now to research inspection ports for PVC and how to clear blocked ducts If I work out how to easily check (and clear if needed) this is probably the best option

Originally Posted by John Samuel

Why not get a Max, rig it with 6 inch pipe everywhere and run it at 50 Hz? If later on you decide you want to be able to run two machines/ports simultaneously, it would be neither difficult nor expensive to drop in a short length of 225 mm pipe with an inspection opening.

Another very good suggestion

Originally Posted by John Samuel

EDIT: Another option would be to do a first-class soundproofing job on the cyclone (perhaps combine two layers of HVAC insulated duct for the exhaust with a soundproofed cupboard) and to always run it at 60 Hz.

To me, this is an added suggestion to either of the ones above. If I get the noise down well enough I will run at 60hz when it makes sense.

I think I know enough (very dangerous statement ) to go for the Max, knowing that I have a bit more 'fiddling' to do but it is much more future proof. Still a bit more navel contemplation to decide on setup but as long as I have understood the principles I can at least make informed decisions

Thanks to all of the helpers out there - especially John, BobL and Ron

cheers

Mick

cheers

Originally Posted by mick59wests

some great things for me to think about. Now to research inspection ports for PVC and how to clear blocked ducts If I work out how to easily check (and clear if needed) this is probably the best option
cheers

BobL responded to a similar query recently and talked about creating a lance with air being provided through it by a compressor.

If the installation were mine and I decided to put in a shortish 8" duct, I likely would do what Bob suggested, make my own 8 inch square duct, but make one side (or the bottom) from 3 mm clear PVC sheet, held in place with self tapper screws and some sealant (or even better a strip of foam door seal). That way you could see if build up was occurring in the duct and the clear PVC could be pulled off in a flash if necessary to do a clean out.