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View Full Version : What do you do to minimize the stink / smell in your house?



Doug Fisher
11-10-2016, 11:00 PM
Laser cutting odor is a real issue for me and I wonder how others cope with this problem. I have searched the archives and read a number of threads but most of them seem to deal with exhaust venting system issues (blowers/piping/DIY charcoal filter systems).

My primary use for the laser at this time is vector cutting acrylic which might be more problematic than etching or engraving. My machine is set up in my home down in the unfinished section of the basement. I have a relatively powerful exhaust fan that sucks the air+smoke through my laser cabinet, then sucks/blows it through 6” tubing and finally out a dryer vent installed in a board that fits into a window. I believe the venting system is sealed well although the Chinese vent fan is always suspect (unfortunately it is not practical to mount the fan outside of the window). The laser cabinet has a vent grille in the lid/door of the cabinet and thus gets a good draw. I don't think the immediate burning/smoke is the primary issue due to adequate exhaust venting, so I don’t think a $$$ commercial or DIY activated charcoal filtering system is going to help.

I think the main issue is the smell from just-burned material as well as deposit buildup on the honeycomb table that is a result of the downdraft which sucks the cutting smoke out from the cut and down through the honeycomb table. There is the classic buildup of darkness on/in the honeycomb table in the shape of the parts I cut.

I try to put the newly cut parts outside for a while to air-out after cutting but winter is coming and I don't know how practical that will be as it get colder. Besides, it can take days for the smell to die down.

I can partially disassemble the laser to take the honeycomb table out and clean it with Krud Cutter but that is not easy on my machine, especially since I found I have to shim my table in its brackets to get the table flat. That is a lot of work, time and won't be easy/practical/fun when it is real cold.

On a related note, I am wondering if the cutting/burning of the protective contact paper isn’t as much of the problem as the cutting of the acrylic itself. Stripping the paper off the cut parts as soon as possible after cutting and then getting that paper outside of the house helps.

I know others here use their machines in their homes, shops and places of business so I wonder what you all do to deal with the odor problem. Any suggestions would be appreciated. About the only additional thing I was considering was creating some sort of cover/wrap that would cover the cabinet when the laser is not used and thus minimize any airflow going in and out of the cabinet.

Since my furnace is located in the basement, when the furnace fires up it draws in some of this smell and distributes it throughout the house. Thanks in advance for any tips you can share.

Glen Monaghan
11-10-2016, 11:33 PM
Run the exhaust for at least 30-60 seconds after a job finishes before shutting off the air flow and opening the cutter lid, so as to make sure you are venting all the free exhaust rather than letting it escape into the room. Where are you getting your acrylic? Do you know whether it is cast or extruded? Most acrylic smells bad when cut, but I think cast smells less than extruded. What I cut certainly doesn't give off smells for anywhere near as long as you describe.

Doug Fisher
11-10-2016, 11:53 PM
Thanks for your reply, Glen. I have been doing that but unfortunately it hasn't been a solution.

My acrylic is extruded. I get it from Calsak which is a big sheet material supplier in the US. Some of the thinner .060" is US made and the thicker 1/8" and 3/16" is from China or Mexico.

I may try stripping off the paper for some of my parts that I cut. Unfortunately, the cosmetics of my parts do matter so taking off the paper before cutting may not be practical (I have had hazing/clouding of the acrylic around the cuts in the past).

Kev Williams
11-10-2016, 11:59 PM
You say it's not practical to place the fan outside the window-- unfortunately, this is the only sure-fire way to get rid of the smell..

With the fan inside, you're pushing fumes into the room thru every crevice in the blower itself and whereever the ductwork is connected. No matter how well the duct is taped or clamped, it leaks. And even if it doesn't, the blower certainly does.

But with the fan outside, every last inch of plumbing inside the house is in a vacuum condition, meaning it's impossible for the ductwork to let fumes escape as it's working hard to suck IN fumes. Your only source of fumes would be what may escape the laser itself...

I have 2 laser blowers and an 80 gallon air compressor outside my house. One blower is in a basement stairwell, the other and the compressor are in an insulated plastic 6'x6' shed. From 50' away, the noise is barely audible from any of them, and they're all in operation 18 hours a day.

In 15 years (over 20 with the compressor) I've only had one neighbor complaint, and that was a few months ago, and it was because my 13 year old HF blower finally had a bearing start to go, and it made a high-pitched squeal the one neighbor told me about. Changed the blower, no more problems :)

Doug Fisher
11-11-2016, 12:07 AM
Thanks, Kev. Yeah, the only window in that part of the basement is near the laser cutter but my house is on a hillside so that basement window is unfortunately about 14 feet off the ground.

I can open doors and the window to vent after cutting. If I get the smell aired out but then close everything back up the smell is soon powerful again so that makes me think my biggest problem is the inside of the machine, recently cut parts stacked waiting for processing and/or any left over acrylic stems/branches or stripped-off protective paper left laying around or in the trash can.

Doug Fisher
11-11-2016, 12:36 AM
Does anyone ever use/put down a layer of Coroplast corrugated plastic sheet material and cut off of that? That would be disposable and my understanding is that corrugated material really weakens a laser's travel. My thought was that material would stop the buildup of yuck inside the honeycomb. I guess the downside is that you wouldn't get the downdraft to pull the smoke downward through the cut and directly to the exhaust port.

Scott Marquez
11-11-2016, 2:28 AM
Here are a few tips.
In the window that you vent out of, ensure you seal the gap that you just created between the sliding and stationary windows.
Open a window across the room to provide makeup air for the air that you are venting out through the laser.
Make a gasket for the output side of your blower fan, it made a big difference on the amount of smell that was being pumped into the room.
When your machine is not in use cover the end of the exhaust tube with a plastic bag and rubber band, also cover the top of your cutting table with a waterproof type of material, I use a piece of truck tarp.
I also run a Hepa filter in the room for about an hour after I finish a large cut job.
Enjoy, Scott

Glen Monaghan
11-11-2016, 8:29 AM
With the window 14 feet above grade, you have at least three choices: 1) run duct from window down to ground level where you put the fan. 2) fasten a shelf to the wall outside the window and mount the fan there. 3) make an in-window mount for the fan (similar to the way a window air conditioner is done). I used a piece of plywood to do option 3 with a Harbor Freight red screamer when I was running the laser in a spare 2nd story bedroom before I built a dedicated studio office and it worked fine plus it made it easy to install and even easier to remove when no longer needed.

Bruce Volden
11-11-2016, 9:18 AM
I use an inexpensive ($80) ozone generator as I hate acrylic cutting. I turn it on after running the plastics and it really works well! I tend to "feel" it in my throat if I'm running it while cutting so I wait til I'm finished!? It doesn't need to run too long to clear the air~maybe 1/2 hour.
Also works for horn/antlers and other obnoxious smells.

Bruce

Gary Hair
11-11-2016, 9:41 AM
You have many things contributing to the smell that you can reduce or eliminate.
1. Get the blower outside. As Kev stated, it's the only way to eliminate the leaks that 100% of blowers have. I mounted mine on a 22' ceiling, a 14' window would have been nice...
2. Clean your laser! The residue left on the honeycomb will smell for quite a while after you cut.
3. Clean your parts or get them outside. Same as the honeycomb, the smell will linger.
4. Get a charcoal filter for the room. It won't really do much good unless you do the first three, they can only filter out so much.

Joseph Shawa
11-11-2016, 10:21 AM
On the outside of the house at the dryer vent I assume there is a flapper valve.
I would try propping the flapper open to allow continuous flow even when the fan is not operating. A passive venting like in modern outhouses. Thank you whoever thought of that. Old school top vented outhouses were miserable!

Maybe even add a 6" riser on the side of the house to increase the flow.

If that isn't enough, run power through the vent hole and mount a computer fan to the flapper and leave it running at all times for active venting.It will open further when your big fan comes on. Should be enough to just keep the smell going the right way. You could also put it on a timer.

Glen Monaghan
11-11-2016, 2:42 PM
Given that ozone reactions don't actually or necessarily produce non-toxic by-products, and breathing free ozone is not particularly good for your lungs, I'd opt for running an air handler with a substantial activated carbon filter (the 1" thick furnace filters marketed as activated carbon filters are totally inadequate) and HEPA filter, much like or even the same as the filtration stack on the laser exhaust. On a number of occasions, I've just left the laser's lid up and left the filtration system running for that very reason. It may not have the best circulation pattern, but it does work in my studio. The AC adsorbs the offensive molecules, trapping them in the carbon pores, whereas the ozone reacts with the same molecules and breaks them into unspecified new molecules, many of which can themselves be unpleasant VOCs.

Doug Fisher
11-12-2016, 10:27 PM
Thanks to everyone for their replies. I appreciate you taking the time.

Tim Bateson
11-14-2016, 9:15 AM
I haven't seen anyone ask - What are you using for your exhaust tubing/pipe? I use to have this problem with the flexible aluminum tubing. I switched to PVC piping and it resolved this issue as well as produces better air flow.