Fume Extraction

[Soren Christensen]

The fans are designed to pull air, not push it. You're better off putting them closer to the vent.

Good point.
So that settles it. It goes closest to the vent hole.

But I will still need to get a small flex duct from the fan to the vent hole.

Update:

have been looking at this one:

https://www.amazon.com/AC-Infinity-C.../dp/B07FPFVZTZ

Just not sure about the blades, seeing as one of the answers on the posting, says plastic. Would that change anything regarding to the smoke?

[Steve Utick]

Good point.
So that settles it. It goes closest to the vent hole.

But I will still need to get a small flex duct from the fan to the vent hole.

Update:

have been looking at this one:

https://www.amazon.com/AC-Infinity-C.../dp/B07FPFVZTZ

Just not sure about the blades, seeing as one of the answers on the posting, says plastic. Would that change anything regarding to the smoke?

I'm running that exact same fan on my Epilog machine here. The AC-Infinity fans have become quite popular in the laser engraving world, a lot of guys using them.

[Soren Christensen]

I'm running that exact same fan on my Epilog machine here. The AC-Infinity fans have become quite popular in the laser engraving world, a lot of guys using them.

Then that settles it
Also I will order one of those flex ducts that is listed as a bundle deal on that page Should be sufficient length with some spare, that I can use from the fan to the vent hole

[Bill George]

Fans can pull or push air. There may be specialized fans designed just for exhaust use but your making this much more complicated than it needs to be. Unless your designing a new system from scratch, duct work and the rest just get a fan rated for the cfm you need and get it done. I worked in the HVAC field for 30 years and taught it for 12 years.

[Soren Christensen]

Fans can pull or push air. There may be specialized fans designed just for exhaust use but your making this much more complicated than it needs to be. Unless your designing a new system from scratch, duct work and the rest just get a fan rated for the cfm you need and get it done. I worked in the HVAC field for 30 years and taught it for 12 years.

I picked this one and some 25' flex ducting.

Just wanted other peoples input on it

[Kev Williams]

late last night (this morning actually ) I was test-cutting some stenciling on paper. To not bother the neighbors I turned on the blower then immediately turned it off. As the blower slowed, I noticed that when the blower was turning very, very slowly, couldn't have been more than 200rpm, it was STILL sucking smoke. Not very fast, but enough it kept the smoke out of the room with the lid open!

[Soren Christensen]

late last night (this morning actually ) I was test-cutting some stenciling on paper. To not bother the neighbors I turned on the blower then immediately turned it off. As the blower slowed, I noticed that when the blower was turning very, very slowly, couldn't have been more than 200rpm, it was STILL sucking smoke. Not very fast, but enough it kept the smoke out of the room with the lid open!

Hehe dosnt most lasers turn off, when lid is open? :O

[Kev Williams]

Most do, yes. All mine will run open or closed...

[Bill George]

I picked this one and some 25' flex ducting.

Just wanted other peoples input on it

Flex duct runs should be as short as possible 6 foot or so, lots of loss. Run hard pipe and then connect the flex where needed.

[Soren Christensen]

Flex duct runs should be as short as possible 6 foot or so, lots of loss. Run hard pipe and then connect the flex where needed.

I know, but running hard pipe isn't gonna help me much, since it will create too many 90 degree bends. From my calculations, it will be atleast 3 bends, where as the flex duct will create smoother than 90 degree bends, hopefully minimizing the effect loss

[Bill George]

I know, but running hard pipe isn't gonna help me much, since it will create too many 90 degree bends. From my calculations, it will be atleast 3 bends, where as the flex duct will create smoother than 90 degree bends, hopefully minimizing the effect loss

Do what you want but flex duct has friction loss from those little ridges inside. Do some online research on Friction Loss in duct work, its all in my ACCA books somewhere.

[Kev Williams]

Sorry but I gotta call BS on all this 'air loss' talk. Yes there's going to be some loss, but it's totally insignificant when it comes to sucking smoke from a laser cabinet. I have an 80 foot run of 4" duct from a big HF blower in a plastic shed outside, across the entire basement ceiling in this place...
this is the end, at my ebay1 fiber, it's 3"
from the blast gate to the laser-
DSC08887.jpg

the blast gate steers some of the suction
to the BIL's C2000 to suck engraving chips-
DSC08888.jpg

From there onward... the reason the vent is just danglingis because at night I have to disconnect from the blast gate
to my LS100 laser to keep a neighbor happy. Look above/left of the paper towels, you'll find another T,
this goes to one of my XT machines, and that black shopvac hose has a hole in it to accomodate the 1-1/2"
PVC pipe you see running parallel to the light fixture, that PVC pipe T's off all over the place to supply suction for
three more engaving machines--
DSC08889.jpg

look close you can see PVC pipe running everywhere-
DSC08890.JPG

--and finally to the other end of the house. Note the shop vac hose...
DSC08891.jpg

The blower and all that hose got put in during 2006, and I've never replaced any of it, just added to it.
And with all that hose and leaky halfassed tees and connections, that blower is still able to suck the
smoke out an LS100, the fiber, and engraving chips from 5 machines, all at the same time.
Yeah, it might suck better with 4" pvc, but other than it's prettier, is it worth it?

And- as fantastically messy as this place appears, if you look close you see that 90% of it is exhaust vent,
computer cables and compressed air lines, peppered with a few zip ties and rubber bands. When it's time to turn this place
back into a house, all that crap can be removed in a few hours with nothing more than tin snips

--and, you've seen the garage, plenty more cheap dryer vent doing it's job just fine...

[Soren Christensen]

Sorry but I gotta call BS on all this 'air loss' talk. Yes there's going to be some loss, but it's totally insignificant when it comes to sucking smoke from a laser cabinet. I have an 80 foot run of 4" duct from a big HF blower in a plastic shed outside, across the entire basement ceiling in this place...
this is the end, at my ebay1 fiber, it's 3"
from the blast gate to the laser-
DSC08887.jpg

the blast gate steers some of the suction
to the BIL's C2000 to suck engraving chips-
DSC08888.jpg

From there onward... the reason the vent is just danglingis because at night I have to disconnect from the blast gate
to my LS100 laser to keep a neighbor happy. Look above/left of the paper towels, you'll find another T,
this goes to one of my XT machines, and that black shopvac hose has a hole in it to accomodate the 1-1/2"
PVC pipe you see running parallel to the light fixture, that PVC pipe T's off all over the place to supply suction for
three more engaving machines--
DSC08889.jpg

look close you can see PVC pipe running everywhere-
DSC08890.JPG

--and finally to the other end of the house. Note the shop vac hose...
DSC08891.jpg

The blower and all that hose got put in during 2006, and I've never replaced any of it, just added to it.
And with all that hose and leaky halfassed tees and connections, that blower is still able to suck the
smoke out an LS100, the fiber, and engraving chips from 5 machines, all at the same time.
Yeah, it might suck better with 4" pvc, but other than it's prettier, is it worth it?

And- as fantastically messy as this place appears, if you look close you see that 90% of it is exhaust vent,
computer cables and compressed air lines, peppered with a few zip ties and rubber bands. When it's time to turn this place
back into a house, all that crap can be removed in a few hours with nothing more than tin snips

--and, you've seen the garage, plenty more cheap dryer vent doing it's job just fine...

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[Bill George]

When ductwork and air flow is done for our customers we started with this > https://www.acca.org/standards/technical-manuals
Of course its all in the computer software today as> https://www.engineeringtoolbox.com/d...ss-d_1122.html



Just because you hang a piece of flex duct and you get air movement does not guarantee the proper cfm or velocity at the machine. Hard pipe has so much less restriction or Friction Loss, plus its not just hanging off the rafters. Hard pipe, balancing dampers and fan sizing is the way its done.

[Kev Williams]

We're not talking about supplying oxygen to the IC unit of a hospital or ventilating a 30 story apartment complex. We're simply sucking smoke out of a laser engraver cabinet, yes?

Just because you hang a piece of flex duct and you get air movement does not guarantee the proper cfm or velocity at the machine...

Yet 10 posts ago you told the OP:

Fans can pull or push air [...] but your making this much more complicated than it needs to be...

But for some reason my version of uncomplicated won't work?

As usual, guess I'm doing it wrong...