I don’t think that is practical for any laser cutter and filter system.
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Hi jason.fuller0,
I agree, not much you can do about the material itself.
What I would be worried about is the material that might give off a less than desirable smoke (toxic) . I work with some rather nasty chemicals and of course we use them in a fumed hood hooked to a scrubber system. It would be nice to get some more specifics from Glowforge on the filter specs.
-D
Well, the point of the filter is to cover you for that stuff, provided it is offgassing from 
. They, naturally, cannot guarantee every possible material, including stuff that isn’t laser safe. At the end, it is let the buyer beware. I throw a LOT of non-proofgrade in my laser, and I’m comfortable with venting or filtering as a rule. Anytime I was in doubt, I’d go full vent over filter. If I’m running proofgrade, no doubts. They may even include a list of materials or substances that are covered by the filter when it is released, don’t know. Either way, if you decide to burn PVC, you are on your own.
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Hi caribis2,
I think it depends on the system and its use. If you run the fan after the job is complete it can remove residual smoke and or particles in the air like jason.fuller0 mentioned the smell gets stuck to the material itself. I think there are several approaches to filtration each solution has advantages and disadvantages. It likely that some systems will do better than others with smoke into the room.
-D
HI jason.fuller0,
That’s an interesting question regarding material.
PVC is a bad material to try and use inside a laser but I am not a laser expert so for me the question is about materials I can use in the laser that produce a toxic fume but are not off limits for the laser itself.
hopefully Glowforge can provide a list, but that’s a big task.
-D
Well, there are many resources other than just Glowforge for detailing what is safe and what isn’t. Even an MSDS, detailing burning hazards can tell you much. My hope with the filter, other than complete filtering of anything bad from Proofgrade, would be a rough list of what substances get filtered so I could compare an MSDS to the filter and say “That’s good”, " vent it", or “no laser”.
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The exhaust system pulls out the particulates, except the particulates that stick to the insides of the laser. I presume these particulates are going to have some odor. Then there is the odor from the material that has just been severely burned. That is why I said practical. A lot of the odor? Sure, but all would mean going to impractical lengths as I analyze it. It sure would be nice, but at the moment I can’t figure out how it would be accomplished.
MSDS is a good start but take them with a grain of salt. The material safety data sheet list hazards of the base material, but it won’t address processing safety for that you have to contact the manufacturer or conduct the testing. I have had many MSDS sheets tell me one thing regarding safety and after processing the MSDS was incomplete. The specific example I am thinking of was a soldering flux we were using in process. We had the manufacturers MSDS stating no bromine was present… which was true in its as delivered state. What we found after we did the processing was bromine all over the place (independent lab testing). The manufacturer provided the “best” MSDS to sell the material, and before you think this is some small manufacturer it wasn’t they were ISO certified etc. and one of the largest companies in there market. While I agree with you regarding the MSDS in my experience it pays to have a little skepticism, but understand the basis for the data being provided.
I am waiting for the specs from Glowforge on the filter. If they are not available by the end of November then I think I will bow out of the filter as I don’t think they will be able to manufacture in time for March deliveries. Right now they don’t have specifications available so they are designing, which given the small filter size they are dealing width is a challenge. They need to finish the design, build protos, and then tool up. They then need to ramp production and start delivery… This is quite the challenge. Which in my opinion means they need a complete design by the end of November. Hard tooling runs about 6 weeks or more so they are running out of time.
-D
Fume hoods do what you are talking about, basically its like operating inside a box that always draws air from the room the odors never get into the room because the negative air pressure drawing room air into it and the odors follow the air flow.
-D
edit: of course as soon as you remove the work piece its going to smell.I have tools inside the fume hoods as a way to clean items I am working on.
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I can say from using it that there is a smell that lingers with the material for a few hours. Like others I thought that was ventilation related, but it really is just attached to the cut material.
Also, I’m kind of limited in space, so this whole setup has to fit into an area not too much larger than what a second glowforge would be at most, preferably able to be put on a cart with it.
So I’ve been spending some time trying to learn what I need to make this work. From what I’ve been able to understand it needs to have a filter with a high enough particulate rating that essentially HEPA is the most cost effective and available option. Without it visible amounts of smoke are still going to come out of the vent. Adding a carbon filter will get rid of some of the nasty acrylic / leather smells that can come from cutting.
Generating enough pressure to get 200cfm through a HEPA filter isn’t easy, so at minimum a decent 6in vent van, possibly an 8in vent fan is required. Some fans like Can-Fan give a nice chart that gives the CFM at certain resistances,
but the problem is the filters easily available are all for home filter units and don’t give much information. The Honeywell round filter used on some of the Instructables for laser fume filters seems like it may be the best option available?
HI Samrcrawley,
Are you going to build a filter?
Keep in mind building pressure is not required for the filter, the carbon needs the air to go slowly over the surface as you are wanting it to adsorb the bad stuff it doesn’t absorb the bad stuff. The filter need stages larger particles removed going down to smaller and smaller. This keeps the filter operating longer.
The least expensive route is to build box on your cart below the Glowforge and use the box store filters to form a progression of filters that remove the particles. You can then use multiple carbon filters in the slots as well. The advantage of the box is you can change the filters from the box store easy, you just make it so they can be slide in and out.
-D
I’m not crazy enough to try and pack a filter with charcoal and hope it will work. Here is the full reference of what I’m currently thinking of. I’m basically following this instructable, but with at least a fan upgrade since it was only estimated at 100cfm.
Fan Options
https://www.amazon.com/VIVOSUN-Inline-Variable-Controller-Ventilation/dp/B01DXYMM2I/ref=sr_1_5?ie=UTF8&qid=1509629391&sr=8-5&keywords=8in+fan
https://www.amazon.com/Can-Fan-Pro-863-CFM/dp/B00GYG39UW/ref=sr_1_1?rps=1&ie=UTF8&qid=1509629596&sr=8-1&keywords=8in+can+fan&refinements=p_85%3A2470955011
Carbon
The filter seems like it should be enough given that the air purifier unit that uses it is rated somewhere around 200cfm. I’m probably going to start with a cheap carbon filter wrap for it since I’m venting it outside and it just has to not be overpowering. If it isn’t enough I’m working on a design that will allow a second box to be added for the upgraded filter.
As long as it will get rid of the huge cloud of smoke the currently results on wood cut jobs and not make quite as big of a stink with acrylic it will be a success.
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Well You are going much more elaborate than I will be. I am also venting outside, but I am just going to use a box like the instructable but I am going to use the existing fan from the unit. I can get large filter frames from Lowes or amazon that pull particles and the same frame can be charcoal based. I am not venting it indoors so it does not have to be perfect. The fan in the photo of the instructable is working with negative pressure, basically just trying to pull a vacuum inside the box (that’s less than 1 atm pressure) . The design I am looking at is setup to slow the air flow by providing a large surface area for the air to flow through, this reduces drag of the filter. The higher the air volume being pushed the more resistance you will see. Your setup will be much better than what I am doing. I guess I am more about just getting the air to be barely acceptable. When I get my shop re-setup I will be making something close to an air scrubber but before I do that I am waiting for Glowforge to come through with the design for there filter. The box with multiple frame filters will work for me for now…
-D
An update on this. First, I did a test run with the 190CFM fan + Charcoal from amazon, since a lot of people have been trying it. It will just result in smoke coming out the greenhouse canister filter. It was easy to return, so I’m glad I at least tried it so people know.
The semi-final solution I now have is the 14" round x 11" HEPA filter I linked above with a charcoal wrap (sold as an add-on for the same filter), the 8" Vivosun fan (~750CFM), and I put the entire thing inside a large plastic tote with holes cut to put vent pipes through.
The end result is pretty good. Smoke seems to be 100% removed, and the odor is manageable outside. I honestly find more problems with smell coming from where the vent hose attaches to the Glowforge (still trying to figure out how to improve that seal).
The solution is a bit of a kludge, but it works well and is very cheap.
Here is an image from it being put together:
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The problem with this is that of concentration. What do I call the stuff coming out of the fireplace - fire generated airborne contaminants? FGACs are bad so don’t have a fire in the house and don’t stand around a campfire outside. And never touch the ashes 
Oxygen is poisonous to humans.
Meanwhile, many of these guys waving the warning flags smoke 
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A filter or Fume Coffin is without doubt going to be contaminated with hazardous chemicals. ALL filters will be contaminated with elevated levels of chemicals. That’s just the nature of filters, they capture stuff.
If you were hoping it converted something dangerous into something benign, then you’re looking at a radical chemical process… a chemical converter. The difference being thousands of dollars worth of setup and operating costs.
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I think that my concern is more about disposal. If they toss lithium ion batteries right into the trash, then perhaps it’s not a concern for others.
Point taken
Ah, yes… I see your point. Depending what you’re doing with your laser, if it’s just natural materials like wood, leather that you’re lasing, then I’m pretty sure you could just bury the charcoal. (Edited to add: or hey, use it for starting a campfire or BBQ pit!)
But if you’re planning on doing lots of paints, plastics or chemical releasing items, then I would think you want to take the waste to an EcoStation for (likely) eventual incineration. High temperature incineration usually handles most things.
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