Fume Extraction

[Soren Christensen]

Hi guys,

I know there are a few posts around (along with tons of YT vids regarding this) but I need another solution, that the DIY fume extractor.

So heres the background:

I have been searching high and low for a decent place to setup shop, but no luck. So I thought that i would keep it at home. However, I live in a flat, so at the time I was thinking about getting a fume extractor. But the more I looked into it, the more $$$ it seemed to cost.

So today I actually had a epiphany and noticed a hole in my kitchen (we arent able to have an extractor hood in the kitchen, something to do with the building being old) which usually "vents" out smoke and stuff after cooking. So I thought to my self. "That would be the optimal place to vent out from the laser".

To give you an idea about the layout of the kitchen ( i have attached a picture of the layout)

440420

NB: the height of the room is 8.43 ft.

So what I was thinking, was to run ducting from the laser and opwards to the cealing, along side the wall and then plug the duct into the "vent" hole, thus venting out above the apartment (above the roof) and not out of the windows. :)

Only thing is. I need to figure out how I actually should pull it off and which kind fan, I would need to make sure the air gets pulled well enough from the laser and pushed through the system and out the hole.

Is there anyone that could give me a few pointers or atleast let me know if this is even possible to accomplish? :confused:


Any ideas or tips would be greatly appreciated

[Nick Marchesani]

I was looking at fume extractors today. I checked home depot and saw these. At the bottom of the page there are many more.

https://www.homedepot.com/p/VENTS-225-CFM-Power-6-in-Mixed-Flow-In-Line-Duct-Fan-TT-150/204629634

[Soren Christensen]

I was looking at fume extractors today. I checked home depot and saw these. At the bottom of the page there are many more.

https://www.homedepot.com/p/VENTS-225-CFM-Power-6-in-Mixed-Flow-In-Line-Duct-Fan-TT-150/204629634


unfortunately, im not in the US :( But it gives me an idea about, what I need :)

Also, im guessing i would need some kind of insulated ducting, to prevent the air noise through the ducting :)

[Steve Utick]

If you have access to Amazon deliveries, they sell a line of inline duct fans under the name of AC-INFINITY that a lot of guys are moving to. They are VERY quiet and move quite a bit of air. Might be something to look into.

[Joe Adams]

unfortunately, im not in the US :( But it gives me an idea about, what I need :)

Also, im guessing i would need some kind of insulated ducting, to prevent the air noise through the ducting :)

I just went through this setting up my Trotec Speedy 300 80w.

It turns out that there's a lot of science involved with understanding air movement dynamics. Unfortunately, neither the laser makers nor the ducting and fan manufacturers were able to offer very much help in figuring out a properly sized system.

Trotec was able to give me the minimum airflow rating at the exhaust port of the machine expressed as a certain amount per minute at a specified pressure. My interpretation was that inline fans did not operate at a high enough pressure to meet this requirement so I went with a radial blade centrifugal fan. That being said, there are a number of members here who use inline fans.

The size, length, and number of bends in the ducting make a big difference. You also want smooth walled ducting for less resistance.

I didn't want to hire an engineer to design my system so I followed the consensus that it's better to have too much airflow rather than too little. This is tricky in an air conditioned or heated space as the treated air will be removed and is replaced by outside air seeping in.

It also depends on what you are cutting or engraving. I was told by multiple people that rubber is the worst in terms of odor.

[Kev Williams]

Just a note on airflow and lasers... Not sure about Trotec but Gravograph's draw air from directly behind the table, thru a 3/4-ish inch wide slot, with the 4" duct exit directly behind that. Works great, in that it draws air across the table. However, fast-moving smoke-filled air being moved across the part(s) your engraving can get covered with the particulates in the smoke. This is bad when engraving any Rowmark signage with a white core, among other things. At night, I started using a quieter blower with only about half the suction on my LS machines to keep a neighbor happy. I found a benefit, in that all my engraving and the entire work surface was cleaner. The lower velocity of air moving lets much of the smoke drift upwards away from the work. The only downside is it takes a few seconds longer to clear all the smoke. Lens doesn't need more cleaning...

Conversely, on lasers like my Triumph, where smoke evacuates UNDER the table, by all means get all the air movement you can afford! You need as much velocity to keep smoke from drifting around above the work for long periods of time, which can collect on the mirrors and lens, which can lead to this-
440475

The nice thing about too much airflow, you can always temper it down with a blast gate. But there's nothing you can to do make a low flow blower move MORE air :)

[Soren Christensen]

I just went through this setting up my Trotec Speedy 300 80w.

It turns out that there's a lot of science involved with understanding air movement dynamics. Unfortunately, neither the laser makers nor the ducting and fan manufacturers were able to offer very much help in figuring out a properly sized system.

Trotec was able to give me the minimum airflow rating at the exhaust port of the machine expressed as a certain amount per minute at a specified pressure. My interpretation was that inline fans did not operate at a high enough pressure to meet this requirement so I went with a radial blade centrifugal fan. That being said, there are a number of members here who use inline fans.

The size, length, and number of bends in the ducting make a big difference. You also want smooth walled ducting for less resistance.

I didn't want to hire an engineer to design my system so I followed the consensus that it's better to have too much airflow rather than too little. This is tricky in an air conditioned or heated space as the treated air will be removed and is replaced by outside air seeping in.

It also depends on what you are cutting or engraving. I was told by multiple people that rubber is the worst in terms of odor.

I see your point. :)

So rather something, like this:

https://res.cloudinary.com/evoleska/images/f_auto,q_auto/v1524360493/product/1588181/ventilationsrr-125-mm-1500.png

And not something like this:

https://res.cloudinary.com/evoleska/images/f_auto,q_auto/v1524338464/product/1581243/pe-isoleret-flexslange-152-mm.png


What about the air noise? Is that considerable or tolerable?

Also regarding the fan, i would be setting up a control for it, to be able to adjust speed, so that I can experiment with the smoke clearing :) I've asked my manufactor to list the min required CFM needed at the exhaust. :)

[Soren Christensen]

If you have access to Amazon deliveries, they sell a line of inline duct fans under the name of AC-INFINITY that a lot of guys are moving to. They are VERY quiet and move quite a bit of air. Might be something to look into.

Only thing is, that I would have to prevent the fan from becoming cluddered with all sorts of debris from the laser.

Or would i simple, just clean it once in a while? :)

But I have looked at the inline fans and they do offer a pretty good CFM and a very reduced sound lvl :)

[Steve Utick]

Only thing is, that I would have to prevent the fan from becoming cluddered with all sorts of debris from the laser.

Or would i simple, just clean it once in a while? :)

But I have looked at the inline fans and they do offer a pretty good CFM and a very reduced sound lvl :)

Any fan that you're using will need to be cleaned once in a while. How often will depend on what you are cutting. If you're cutting a lot of wood, you will get residue on the blades that necessitates cleaning more often. Any screen or anything you put inline to try and prevent that will clog up sooner, reducing your airflow and compounding problems. The AC-Infinity fans come apart very easily for cleaning as well.

[Kev Williams]

Just want to mention that I'm not much of an 'overthinker', and I really don't care about 'pretty'...
...All I care about is that my stuff works.

That said, just wanted to show off MY fume extraction 'system' (lol) --the garage version--
440599
I took this pic standing at door to my garage shop, my 2nd ebay fiber is directly to my right out of view,
and my rotary tool cylinder engraver is to my left. On the back wall of the garage hangs
a cluster*&$! of vent hoses from bulk red wiretie and bent welding rod. Just plain old
dryer vent, 3, 4 and 6", one splits between my GCC Explorer and the fiber you can't see, the other line
splits between the big Triumph laser and my Triumph fiber right in the middle of the pic.
Each duct line has a gate, and 2 HF blowers sitting outside under the plex garage window
inside a plastic patio storage box do all the extracting...
440601
I can generate a ton of smoke and ash at times, and it all gets sucked away just fine :)

[Soren Christensen]

Just want to mention that I'm not much of an 'overthinker', and I really don't care about 'pretty'...
...All I care about is that my stuff works.

That said, just wanted to show off MY fume extraction 'system' (lol) --the garage version--
440599
I took this pic standing at door to my garage shop, my 2nd ebay fiber is directly to my right out of view,
and my rotary tool cylinder engraver is to my left. On the back wall of the garage hangs
a cluster*&$! of vent hoses from bulk red wiretie and bent welding rod. Just plain old
dryer vent, 3, 4 and 6", one splits between my GCC Explorer and the fiber you can't see, the other line
splits between the big Triumph laser and my Triumph fiber right in the middle of the pic.
Each duct line has a gate, and 2 HF blowers sitting outside under the plex garage window
inside a plastic patio storage box do all the extracting...
440601
I can generate a ton of smoke and ash at times, and it all gets sucked away just fine :)

I love your little maker space :D To hell with the clutter :D

Btw, do you have any problems with the flex hoses? I mean some people say that the ducting should be with the most smoothes surface?

[Soren Christensen]

Any fan that you're using will need to be cleaned once in a while. How often will depend on what you are cutting. If you're cutting a lot of wood, you will get residue on the blades that necessitates cleaning more often. Any screen or anything you put inline to try and prevent that will clog up sooner, reducing your airflow and compounding problems. The AC-Infinity fans come apart very easily for cleaning as well.

Only thing left, is really at which end do I need to put the fan? Close to the machine or at the exhaust venting out? Pros and cons?

[Kev Williams]

I love your little maker space :D To hell with the clutter :D

That's just the garage, you haven't seen the basement :)

Btw, do you have any problems with the flex hoses? I mean some people say that the ducting should be with the most smoothes surface?

Speaking of the basement:
440701
this pic, which was laser engraved by my LS900 onto 1/8" thick NON-laserable New Hermes black/white '2-plex', I did about 7 years ago. All of the silver ductwork sprawled all over the ceiling is still there, and was about 8 years old when I took the pic! I'm sure it doesn't move as much air as smooth PVC would, but seriously, since it's just moving smoke, the improvement wouldn't be all that noticeable...

[Soren Christensen]

Speaking of the basement:
440701
this pic, which was laser engraved by my LS900 onto 1/8" thick NON-laserable New Hermes black/white '2-plex', I did about 7 years ago. All of the silver ductwork sprawled all over the ceiling is still there, and was about 8 years old when I took the pic! I'm sure it doesn't move as much air as smooth PVC would, but seriously, since it's just moving smoke, the improvement wouldn't be all that noticeable...

How about air noise? Is it noticeable or not? :)

[Steve Utick]

Only thing left, is really at which end do I need to put the fan? Close to the machine or at the exhaust venting out? Pros and cons?

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

[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. :eek:

Update:

have been looking at this one:

https://www.amazon.com/AC-Infinity-C.../dp/B07FPFVZTZ (https://www.amazon.com/AC-Infinity-CLOUDLINE-S6-Controller/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. :eek:

Update:

have been looking at this one:

https://www.amazon.com/AC-Infinity-C.../dp/B07FPFVZTZ (https://www.amazon.com/AC-Infinity-CLOUDLINE-S6-Controller/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 :D

[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-
441031

the blast gate steers some of the suction
to the BIL's C2000 to suck engraving chips-
441033

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--
441034

look close you can see PVC pipe running everywhere-
441035

--and finally to the other end of the house. Note the shop vac hose...
441036

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 :D

--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-
441031

the blast gate steers some of the suction
to the BIL's C2000 to suck engraving chips-
441033

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--
441034

look close you can see PVC pipe running everywhere-
441035

--and finally to the other end of the house. Note the shop vac hose...
441036

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 :D

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

Check your inbox :D
Sent you a message :)

[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/ductwork-friction-loss-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...

[Bill George]

Long runs of flex vs hard pipe, the hard pipe has less restriction to air flow = more flow for less fan HP. Equals less power consumed. Kev if what you run works for you that's all you need. You certainly are very good at the laser business and so knowledgeable.

I worked with engineers and they wanted it done so when the customer turned the system on it did move the specified amount of air at the lowest energy cost.

My own system. Inline fan, short 3 ft intake to fan, 6 feet to outside exhaust vent and yes its flex.