[joshpit2003]

Hey Guys,
Long time lurker here.

Indistrial Designer,
Worked with laser machines in and out of school,
I'm about to pull the trigger on a Thunder Laser Mars 90 100W machine.
(it has an ~36" x ~24" work area) and here is the pdf of specs: http://image.thunderlaser.com/images...log/Mars90.pdf

I'm just awaiting approval from my building manager to cut the 6" hole in the ceiling for exhausting fumes.

I plan on blowing air up 20 feet (through ~25' of 6" diameter metal duct) to exit 3 feet above the roof.
I plan on cutting a lot of Acrylic/wood.

My two concerns:

Noise:
I know blowers can be very loud, and I know the noise-level varies from blower-to-blower.
Putting the blower on the roof seems like an ideal solution, but isn't really something I'm interested in doing.

Smell:
I'm not sure if the smell exhausting onto the roof will be a problem (i doubt it), but if it is I may be able to capture it in-line w/ some of the filtering options I'd seen.
I'm more concerned about smell inside my live/work loft where the machine will be located.


My pondered solutions:

Noise:
It seems there are quite a few "low noise" blowers thanks to grow-ups being popular. Here's an example:
Amazon.com : CFM PRO Premium 6" Inline Air Blower Fan - Suitable for Hydroponics Ducting or other Exhaust System : Built In Household Ventilation Fans : Patio, Lawn & Garden
I figured I could either:
1. Buy a low-noise blower (if I can find one adequate enough)
2. Insulate a loud blower inside of a box (if that doesn't over-heat the thing)

Smell:
The machine has vents that allow room-air to feed into the machine for the exhaust.
I was thinking that I could design carbon filters that would be held over these vents, and run tape along the machines door-seams to prevent smells from escaping.


Thoughts?

Thanks.

[agrasyuk]

noise: anything with universal motor (i.e. the harbor fright little red blower) will scream. induction motors however will be very quiet , with my household HVAC blower i hear the sound of air whooshing through the ducts and filter media more then anything.
smell: your machine will have negative air pressure inside, all the ventilation holes in it are for air to get in. why block inflow of air into machine with filters?
you will have smell, acrylic for example will continue to outgass for some time lafter cutting / engraving. to minimize the smell i tend to have the fume extractor work non stop thorough entire worksession and i leave the lid closed for at least 10 seconds after each job is done to evacuate as much fumes as possible from the enclosure.

as far as exhausting through the roof, i tried it(pick of first attempt ).. with the amount of air blown out the replacement air was drawn in via garage suffits and i was getting some unfiltered fumes back - really bad. running unfiltered you are risking neighbors complaining, that stuff can smell quite far. so i would definitely plan on some sort of fume scrubbing.

[joshpit2003]

Thanks for the response.
And thanks for the motor tip. I figured the stock motor would be a screamer, so I plan on ordering an alternative.

I noticed you put your blower right up near the ceiling to pull air up the ducts.
I was planning on putting the blower almost immediately after the machine, to push air up the ducts.
Not sure if that makes much of a difference.

Regarding fumes:
I'm looking at something like this:
http://www.amazon.com/iPower-GLFILT6..._bxgy_lg_img_z
and I figured I could build a box to fully enclose it and mount it on the floor or wall in-line with the ducts.

Not sure how often I'd need to replace the carbon, but the item seems relatively in-expensive, so even 2X a year would be fine with me.

How are you running your exhaust, and how are you scrubbing fumes?

-Josh!

noise: anything with universal motor (i.e. the harbor fright little red blower) will scream. induction motors however will be very quiet , with my household HVAC blower i hear the sound of air whooshing through the ducts and filter media more then anything.
smell: your machine will have negative air pressure inside, all the ventilation holes in it are for air to get in. why block inflow of air into machine with filters?
you will have smell, acrylic for example will continue to outgass for some time lafter cutting / engraving. to minimize the smell i tend to have the fume extractor work non stop thorough entire worksession and i leave the lid closed for at least 10 seconds after each job is done to evacuate as much fumes as possible from the enclosure.

as far as exhausting through the roof, i tried it(pick of first attempt ).. with the amount of air blown out the replacement air was drawn in via garage suffits and i was getting some unfiltered fumes back - really bad. running unfiltered you are risking neighbors complaining, that stuff can smell quite far. so i would definitely plan on some sort of fume scrubbing.

[agrasyuk]

I noticed you put your blower right up near the ceiling to pull air up the ducts.
I was planning on putting the blower almost immediately after the machine, to push air up the ducts.
Not sure if that makes much of a difference.

it makes lots of difference. on the low pressure side (before the fan) any tiny leak in your duct-work will just suck air in. any leak on the high pressure side of the fan will push the fumes contaminated air back into room you are in. so you will want the fan to be as close to exhaust as possible


Below is picure of my DIY filter setup with front panel removed (air assist compressor in bottom compartment). that same household HVAC blower exhausts the air outside through square port in wall (guarded by louvers on the other side). fumes are drawn through regular household airfilter first to clean any solid debrisand then through box with 6" layer of activated carbon . carbon restricts the flow quite a bit, so its good to start with a very capable fan. as i said it is very quiet solution
Attachment 271980

closeup of carbon box (empty)

Attachment 271982
ADD:
i changed the laser machine since

[joshpit2003]

Thanks for the pic.
I'm not sure I'll be running a pre-filter (like your household filter) before the carbon, I just don't really see any harm in particles making it to the carbon filter.
I'd also be a little concerned that a household filter like the one shown would be waiting to catch fire the instant the smallest flame touches it. But that may be an irrational fear.

I guess my remaining Q's:
- How much stuff are you collecting w/ the houshold filter and do you really think it's worth the added flow-reduction?
- What CFM is your blower?

Thanks again.

fumes are drawn through regular household airfilter first to clean any solid debrisand

[agrasyuk]

Not going to argue on whether its possible, but i never heard of filters burning up.

The paper prefilter collects dust and there will be plenty of it in the air. With time that dust will plug the carbon reducing flow and efficiency considerably. Its much easier and cheaper to replace a simple paper then carbon. I actually missing a layer , there should be a HEPA filter between the paper and carbon that supposed to catch finer particles.

That blower is rated 1500 CFM I think, to be safe I'll say 1200. I never measured the airflow with all the restrictions, but after stock fan and then non-filtered bathroom fan attempt(silly me ) I find it very adequate.

Good luck with your project. Lasers are very fun )

[amders]

it makes lots of difference. on the low pressure side (before the fan) any tiny leak in your duct-work will just suck air in. any leak on the high pressure side of the fan will push the fumes contaminated air back into room you are in. so you will want the fan to be as close to exhaust as possible


Below is picure of my DIY filter setup with front panel removed (air assist compressor in bottom compartment). that same household HVAC blower exhausts the air outside through square port in wall (guarded by louvers on the other side). fumes are drawn through regular household airfilter first to clean any solid debrisand then through box with 6" layer of activated carbon . carbon restricts the flow quite a bit, so its good to start with a very capable fan. as i said it is very quiet solution
Attachment 271980

closeup of carbon box (empty)

Attachment 271982
ADD:
i changed the laser machine since

see your attachment... can you share on how to make it?

thanks..

[agrasyuk]

i sure can share, but i think the pictures are quite self explanatory, no?
sizes were driven by my workshop space limitations - wider would have been better . after the pics were taken the only addition was vertical plank on right sidewall for vertical panel to rest on and weather-proofing foam strips to help seal. when the blower is working the front panel is sucked in due to lower pressure inside resulting in a very good seal.
and this design is not really the most correct, as i said i'm missing a layer of HEPA filtering between the paper and carbon (if anyone has a beat on reasonably prised 14"wide HEPA i will really appreciate it)

what would you like me to elaborate on?

regards.
Anton

[bratan]

That's great filter! I think I'm going to build something like this. I have a bunch of questions if you done mind
So you have your motor on the bottom, it takes air from the front intake, and just blows it back or you have 90-degree elbow?
Do you have any leaks, smell coming out when working? Does it take exhaust outside or blows it back into the room? Any reason you made it this tall?

[agrasyuk]

i don't mind answering.
the blower motor is actually at the very top and indeed exhausts outside. on the bottom i have a dedicated shelf for my tankless air assist compressor - that compartment is isolated and does not participate in anything filtration related. the air inlet is via 4" blastgate (visible on first picture at about table height level) so i can use the ordinary shop dust collector tubing to connect to exhaust port of the laser.
the reason for the motor being so high up there is :
1. the air output on the other side to be protected from rain (its under roof suffit),
2. all of my sloppy construction is on low pressure side of the blower , meaning that any imprefections are not going to leak fumes back into the room.
3. in future i plan to have another air inlet blast / gate above the carbon box for colapsible spraybooth and sawdust evacuation from my circular saw (i don't care for whatever particles that manage to escape centrifugal dust separator to get scattered outside).

no smell when i'm working, it does however smell when opening the lid of the machine (acrylic will outgass for some time after cutting). to minimize the smel i tend to leave the lid closed for at least 10 seconds after job is finished, longer if I feel patient at the moment, or if i'm cutting thick material (6mm acrylic smells much stronger).


I guess i'll make another picture of the entire thing from a different angle when i'm home to make things clearer

regards,
Anton