Can't get 100% of smoke/smell to exhaust out

[Todd Mueller]

i have a 600mmx400mm chinese laser cutter, with a lid

I cant keep all the smell going out, I have both a 273 cu feet a minute squirrel/furnace style fan and the fan that came with it which is similar style just a little smaller, and both of them running together and it still doesnt seem to be enough, which I absolutely cant have.
I have tried opening the top which visibly makes it look like all the smoke is rushing out,
keeping it half open,
putting tape around the seems of most of the doors,
taping the vents that are factory cut into the door and removing a long thin rectangular panel right below the top cover/door to try and draw air from a little below the table and keep smoke from being right by the vents in the door/top.
both fans have their own 4" duct that I mounted to a board in a window in that room and then closed the window against it and taped around the edge.

any tips, I have seen people online with a laser cutter in their office room in a house, and surely they are getting all of the smoke/smell out?

[Tony Lenkic]

Todd,

Smoke and debris is what blower must remove. Smell is another matter.
Once you cut your substrate the pieces are still in laser cabinet that will produce smell for extended period and if left indoor you will produce that smell.
If you have place to remove end store them out of working area you will minimize lingering smell.

Note: Do not mask cabinet openings as they serve the purpose (intake air) .

[Scott Marquez]

I would suggest opening a window on the other side of the room for new air to come in, which will allow your fans to work their best.
I vent my exhaust out the window in a similar fashion as you have described, you will also need to fill the small gap between the window panes that you created when you opened the window. I have a long slender piece of foam that I use to seal the gap.
Let me know if doing both of those things helps.
thanks, Scott

[Al Launier]

You might consider this http://shop.naturalmagic.com/All-Pro...shed-Cotton-14. I don't have a laser cutter, but have found this product to effectively absorb/eliminate odors from painting, etc. I prefer the "Brushed Cotton" as it leaves a nice clean scent, not perfumey. For more severe odors I use it in conjunction with an air filtration system to help remove "scented" air particles.

[Bill George]

The smoke smell is telling you your system is not working. To remove air you need to bring in air in the front of the cabinet, and then out the rear port to a sealed opening in a outside wall or window. If the outside wall or window is not sealed you may get smell back inside. . Or you may have a negative in the room caused by another exhaust system running. If you put a lighted candle inside the cabinet with your exhaust fan on and close the lid the flame should bend toward the exhaust slot or port..

[Todd Mueller]

Todd,

Smoke and debris is what blower must remove. Smell is another matter.
Once you cut your substrate the pieces are still in laser cabinet that will produce smell for extended period and if left indoor you will produce that smell.
If you have place to remove end store them out of working area you will minimize lingering smell.

Note: Do not mask cabinet openings as they serve the purpose (intake air) .

I have masked just some of the seems of doors on the sides of the cabinet as a test, there are many. But while i do this I am finding leaving the top/hood door open or cracked helps a ton, you can visually see the smoke rushing back and downward. i believe though that when the machine is making cuts near the very front of the machine, nearest the door, is when probably little bits are escaping. I have just under 500 cu ft/min of air, and am starting to think that somewhere around 800 cu ft/min would be much better. Could help to clear the front edge while cutting better

[Todd Mueller]

I would suggest opening a window on the other side of the room for new air to come in, which will allow your fans to work their best.
I vent my exhaust out the window in a similar fashion as you have described, you will also need to fill the small gap between the window panes that you created when you opened the window. I have a long slender piece of foam that I use to seal the gap.
Let me know if doing both of those things helps.
thanks, Scott

I have actually worked with this today. this is in an unfinished basement, and the room with the laser is on the opposite side of the basement from a walkout slider door. i have opened the slider door and then also taped around the board and the area where the two windows meet but are partially open, effectively sealing all of the areas around the window, it has helped a ton, so i dont believe anything is coming in through the window area, during this time i also shut off the furnace/blower for the house so that nothing from that system was pulling anywhere... just one slider door open and the two exhaust hoses going out the board in the window.

the room still gets smelly, a fair amount, and just really am starting to think i need more like 800 cu feet/min of fan power

[Todd Mueller]

The smoke smell is telling you your system is not working. To remove air you need to bring in air in the front of the cabinet, and then out the rear port to a sealed opening in a outside wall or window. If the outside wall or window is not sealed you may get smell back inside. . Or you may have a negative in the room caused by another exhaust system running. If you put a lighted candle inside the cabinet with your exhaust fan on and close the lid the flame should bend toward the exhaust slot or port..

yes, i havent put a candle in the machine but no doubt the flame would get pulled back, when i watch the thing, it appears that all of the smoke is quickly rushing down and back, but the smell is still there, i do understand about the residual smell, but that is not what im talking about, the smell increases pretty drastically while cutting. I suspect the smoke/smell is escaping from the top/hood and mostly only when cutting near the front.

[Todd Mueller]

Lots of great tips/advice so far, here is what i am thinking for my next test since I am so bent on thinking the smell only escapes during cutting near the front of the machine

i will program some cuts that only happen near the rear, and see if the smell enters the room, that would at least confirm whether or not my theory is right, if it stays smelling clean, then i will know that i have no leaks from the exhaust or around the window area, which I really don't think that i do but anything is possible.

If i find that it works perfect for rear cuts but not for front cuts, it would seem to me that i probably near more exhaust power

any thoughts on this approach?

[David Somers]

Todd,

An additional thought. Is your blower near the start of the hose/pip run pushing the air out through a length of hose that is in your room? Or is it at the far end of the run of hose/pipe pulling the air through that length? If you are pushing you are probably pushing air out through all the seams and imperfections in the hose/pipe. If you are pulling it you will have negative pressure in all those lengths and reduce the amount of seepage into the room. I rarely have problems with odors in my garage until i actually open the laser. My blower is outside of the room pulling air for all but about 2 feet of length of hose. It works very well.

[Keith Winter]

That's not enough cfm. Chinese machines sold as a set tend to under power their chillers and exhaust fans. Do yourself a favor and buy a $100 Hf dust collector. Toss the bags and use it as your exhaust fan instead. Cheap solution and will help the issue dramatically. Also seal seams/Windows near the exhaust point outside. Seal all joints alomg your duct work with metal duct tape. Make sure you have no big kinks in your duct lines.

After all that is done. As others have said many materials produce a smell after being cut. All you can do is store them outside or elsewhere for a few days if the smell bothers you. One thing to consider if the smell bothers you, how close are your neighbors, and will smell coming out of your house bother them? What material in particular are you cutting that the smell is bothersome?

i have a 600mmx400mm chinese laser cutter, with a lid

I cant keep all the smell going out, I have both a 273 cu feet a minute squirrel/furnace style fan and the fan that came with it which is similar style just a little smaller, and both of them running together and it still doesnt seem to be enough, which I absolutely cant have.
I have tried opening the top which visibly makes it look like all the smoke is rushing out,
keeping it half open,
putting tape around the seems of most of the doors,
taping the vents that are factory cut into the door and removing a long thin rectangular panel right below the top cover/door to try and draw air from a little below the table and keep smoke from being right by the vents in the door/top.
both fans have their own 4" duct that I mounted to a board in a window in that room and then closed the window against it and taped around the edge.

any tips, I have seen people online with a laser cutter in their office room in a house, and surely they are getting all of the smoke/smell out?

[Todd Mueller]

Todd,

An additional thought. Is your blower near the start of the hose/pip run pushing the air out through a length of hose that is in your room? Or is it at the far end of the run of hose/pipe pulling the air through that length? If you are pushing you are probably pushing air out through all the seams and imperfections in the hose/pipe. If you are pulling it you will have negative pressure in all those lengths and reduce the amount of seepage into the room. I rarely have problems with odors in my garage until i actually open the laser. My blower is outside of the room pulling air for all but about 2 feet of length of hose. It works very well.

the fans are at the far end of the hoses not at the machine end, they are literally mounted on the board that sits in the window, so they pull air the whole run, no pushing at all.

[David Somers]

Thanks Todd! In that case I agree with others, you are likely not getting enough CFM. Keith mentioned the Hf dust collector a few messages above? By Hf he means Harbor Freight. Just FYI.

[Todd Mueller]

That's not enough cfm. Chinese machines sold as a set tend to under power their chillers and exhaust fans. Do yourself a favor and buy a $100 Hf dust collector. Toss the bags and use it as your exhaust fan instead. Cheap solution and will help the issue dramatically. Also seal seams/Windows near the exhaust point outside. Seal all joints alomg your duct work with metal duct tape. Make sure you have no big kinks in your duct lines.

After all that is done. As others have said many materials produce a smell after being cut. All you can do is store them outside or elsewhere for a few days if the smell bothers you. One thing to consider if the smell bothers you, how close are your neighbors, and will smell coming out of your house bother them? What material in particular are you cutting that the smell is bothersome?

Great tip on fans, i just looked at harbor freights website and they have 2, for $149 which is 660 cfm, and one for $229 which is 1550 cfm,
I have 2 fans right now, and would guess i have somewhere between 425 cfm and 500 cfm max. The one fan i have been thinking about, if I determine that is the best route is this one
http://www.amazon.com/Dayton-Model-1...=dayton+blower
Daytons are great fans, and this one is a 2 speed with the max speed handling 800 cfm for $208.00, which to me if i used 6" exhaust seems like it would handle anything i threw at it, but not sure. that one from harbor freight that does 1550 cfm would be a ton of air movement but I am thinking about if that might be overkill and also the amount of conditioned air it would remove from the house, but whatever the case i need to make sure all of the smell/odors are removed, whatever the solution... I would use short straight pipe 6" exhaust tube with whatever option i chose to go with.

[Keith Winter]

Elaborate on the you have two fans comment. Do you have two lasers or what is the other hooked up to?

Great tip on fans, i just looked at harbor freights website and they have 2, for $149 which is 660 cfm, and one for $229 which is 1550 cfm,
I have 2 fans right now, and would guess i have somewhere between 425 cfm and 500 cfm max. The one fan i have been thinking about, if I determine that is the best route is this one
http://www.amazon.com/Dayton-Model-1...=dayton+blower
Daytons are great fans, and this one is a 2 speed with the max speed handling 800 cfm for $208.00, which to me if i used 6" exhaust seems like it would handle anything i threw at it, but not sure. that one from harbor freight that does 1550 cfm would be a ton of air movement but I am thinking about if that might be overkill and also the amount of conditioned air it would remove from the house, but whatever the case i need to make sure all of the smell/odors are removed, whatever the solution... I would use short straight pipe 6" exhaust tube with whatever option i chose to go with.