Thread: Hafco W318 dust extractor.

Gotto go will post more photos later.

OK - I see what you have done now, you have mated the old impeller to the cyclone.

But

Hhas the cyclone been resized to suit the impeller?

Remember BPs cyclone is designed for a 15 or 16" impeller and your impeller is 12"?
Somewhat counterintuitively the cyclone has to be made with a larger diameter to suit a smaller impeller.
That impeller only produces about 8" of WC and it will lose 6.5" of WC to the impeller meaning their won't be much levant over for air flow.

BobL, I used Bill Pentz excel spreadsheet BUT I have to make it calculated for a 4hp cyclone instead for 3hp because 3hp cyclone would poke though the roof
It almost touch the it with 4hp cyclone in my case using the w310 dust bin.

Took some readings at table saw and drop saw

Those types of anemometers are not the right sort instrument to use for narrow ducts and pipes - they are designed for very large cross sections like doors or windows, or large AC ducts with cross sectional area 10 times or more larger than the entire anemometer head.
My experience with them is that when used with narrow ducting they over estimate the flow by between 20 and 40%.
Have a read of the sticky in the dust forum about measuring air flow.
DRAFT: FAQ - Dust Extraction (Practical Aspects)

Even using the correct measuring anemometer you can't just poke it in front of a duct or tube opening like that - read the sticky and it will explain how to measure air flow correctly.

I need helps on deciding where to put the vent, through brick wall and down or the tin roof and over rain gutter ducting down???
some photos for visual.

This one let us setup the ft² of the duct opening, don't know if it accurate enough, this is for 6" pipe.

RE: Vent location.
If you or your neighbours don't care about noise I'd go out through the roof. Don't use a Whirly-bird the will provide too much back pressure when the wind is not blowing. You could use a witch had chimney but make sure it's at least 9" or 12" diameter
If noise is going to be an issue you will need a muffler - I'd add an 8+" diameter vertical muffler down to near the floor and then go out through the brick wall near the floor.
Do you know what is involved with a muffler?

Originally Posted by Hoey

This one let us setup the ft² of the duct opening, don't know if it accurate enough, this is for 6" pipe.

Sure I understand how they work, I have used that type at work.
Read the sticky and that that will explain why they are not accurate on 6" ducting.
Like I said above, they over estimate the flow by between 20 and 40% they are also not that good at relative measurements so you cannot use them to make decisions - eg is this better than this?

Don't no if this will works, my intention is to use 50x200 sleeper to make box/duct over the roof then box/duct down the wall using pocket hole to joint then i can line the box/duct with cheap sound proof

Pipe should not be used inside a muffler as it stops the sound from getting absorbed and just carries the sound forward . Just some rock wool inside the box held in place with some chicken wire or similar is all that is needed.

Not sure how unobtrusive a "roof exit and boxed over duct" you can do in that situation given you have to clear the gutter

Also roof exit will require 3 right angle bends whereas an internal muffler only requires 2.
Internal muffler can be made out of 16 or even 12mm MDF.

Box is the duct. Mdf box on the inside joints sleeper box over roof, motor/impeller to keep them cool then joints the wall box down. The start of the gutter will be removed about 500mm for wall box. The corner of the garage is alot less than 90° that is why the gutter is there otherwise not needed.

Maybe a few dollars into the fence first...

Originally Posted by woodPixel

Maybe a few dollars into the fence first...

Nah, it's all good and still standing plus the wifey hasn't said anything yet

If you were to rotate the outlet 90 degrees to cut a hole in the brick would it hit the welded truss? if it clears the truss the air would enter straight into the muffler box on the outside and cause the least resistance to the exhausting air. If the truss is in the way then my suggestion is out.

Is putting the entire cyclone outside in a lean to enclosure possible? Get a little extra floorspace that way too.

Pete