Build a Laser Cutter Fume Extractor

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I run a small design consultancy specializing in custom electronic prototypes and one-off builds

Intro: Build a Laser Cutter Fume Extractor

I built my first laser cutter in 1996 and learned right away that laser cutters "stink". Well, at least the fumes from cutting smell awful and are quite harmful to breath. After trying several fume extraction options, back in 2002 I found the ElectroCorp RSU filter. It was a bit expensive, I think I paid $1500, but it did a great job extracting even the worst fumes from cutting acrylic. Fast forward to 2013, I called up ElectroCorp to buy replacement filters for my unit and found out that the original company was sold and is now being run by another company. This new company claimed to supply the same replacement filters, but after almost three months of going back and forth with them, it turns out that their filters are no longer the same, cost way more and look to be much less robust. Going through this challenging and frustrating process with them got me thinking. After taking a close look at how my old unit worked, it was pretty clear that I could build a similar unit quite easily that would allow me to use off-the-shelf and readily available parts. I figured I would document the process so other people with laser cutters could try their hand at doing the same. Depending on the supplies you have laying around your workshop, you should be able to build one of these for somewhere between $400 and $450. Here's how...


Step 1: Gather Major Components and Supplies

Parts:

Tools:
  • Plunge router with a straight plunge bit
  • Electric staple gun
  • Drill (with Phillips tip and 3/8" drill bit)
  • Jig saw
  • Hot glue gun
  • Hearing protection
  • Face mask
  • Dust mask
  • Rubber gloves

Step 2: Cutting Disks and Rings

I started out making a jig for my router. If you have a circle cutting jig you can obviously skip this step. We need to cut two inner and two outer rings plus the top and bottom plate (note that the bottom plate doesn't have the 6inch hole in the center). I used the jig saw to cut out the top and bottom plate.

Remember to wear all your safety gear!

Step 3: Install the Casters

Figured it would be easiest to do this now. Just screw them to the base plate (the one without the hole).

Step 4: Staple the Screen and Mesh Into Place

iThe goal is to end up making two cylinders with the sets of inner and outer rings that are just a little taller than the hepa filter, which is 12" tall. I started by cutting strips of the 1/4" wire cloth 12" wide. I stapled this to the outside of the smaller inner rings and the inside of the larger outer rings so that the total height of each cylinder is 12-1/8". Then I lined the wire cloth with the fine window screen. I used a ton of staples since I wanted to be sure it didn't come apart and that there was no gaps between the wood and the mesh.

Step 5: Glue the Mesh Cylinders Down to the Base With Silicone

I drew a circle on the bottom plate so I would know where to position the inner cylinder. Then I ran a bead of caulking around the circle and squished the cylinder into place. I did the same with the outer cylinder.

Step 6: Filler' Up With Carbon

The carbon comes in something like a potato sack. I recommend you leave it in the box it's shipped in as there is fine carbon dust that seeps through the bag. I just used a cup and filled up the space between the two meshes. It is a bit messy so I would do it outside on a surface that you don't mind spilling a little carbon.

Wearing a dust mask and gloves is a great idea for this step.


Step 7: Clean Up and Add Some Weather Stripping

Clean all the carbon dust off of the top edges of the inner and outer rings. Vacuum out the center area. Apply weather stripping to both the inner and outer rings. I also added some weather stripping to the underside of the top plate.

Step 8: Cut the Bottom Gasket

I cut a circle out of the shelving liner that was approximately the same size as the outer diameter of the hepa filter. I then placed it in center area so the hepa filter would sit on top of it and no fumes would leak under it.

Step 9: Build the Pre-filter

To save you from replacing your hepa filter as often, there is a pre-filter that filters the "big" particles. To make it, I cut a 11-3/4" x 25" piece of the 1/4" wire cloth and rolled it into a cylinder overlapping the ends by about 2". Then I used some gaffers tape wrapped around the top and bottom edges to hold it together. I cut the 1/4" Duck Brand foam to fit inside the cylinder and both layers of the 3M Filtrete filters to fit on the outside of the cylinder. A piece of gaffers tape holds the 3M filters together.

Step 10: Build the Mat Board Air Baffle

Having a laser makes cutting cardboard a breeze, but you could probably do the same by hand. Take a look at the attached DXF file.The baffle needs to fit snugly inside the pre-filter. It should be pretty easy to tell how it goes together. I used a fair bit of hot-glue to make sure there were no leaks. You might need to adjust the dimensions a little if your pre-filter cylinder is slightly different dimensions.

Step 11: Bolt It All Together

I cut the threaded rods to 15" and bolted everything together. You will want to tighten all the bolts evenly to compress the weather stripping straight down.





Step 12: Wire Up the Fan

I cut the male end off an old extension cord and wired it into the fan's junction box. I used a Romex clamp to provide strain relief. Then I plugged the extension cord into the variable speed router controller (which is just a high current rheostat). You could just add an on/off switch, but I like to be able to turn the fan down when cutting thin material like paper, so that it doesn't get blown around.

Step 13: (Update!) Post Filter

My old unit had this blue fuzzy filter on the outside of the carbon filter (see the picture at the beginning of this Instructible). I never could figure out why it was there since the carbon did such a good job removing the fumes. What could be left to filter out? Fortunately, Soundgod06 posted a comment asking if I saw carbon dust blow out when I turned on the filter. The answer was no, I didn't see any dust, but it got me thinking... Just because I couldn't see it, doesn't mean it wasn't there. Ah ha! THAT'S why the blue fuzzy filter was there. It's there to grab any carbon dust pushed out by the blower. It was simple enough to add, I just ordered a roll from McMaster for $19, cut it to fit in between the top and bottom plates and pressed it into place. I just overlapped the filter material at the end, and tucked the free end behind one of the threaded rods. It holds there quite nicely.

Step 14: Test It Out!

Plug it and flip the switch! It should draw quite nicely when on high. Hard to say what the final CFM rating would be, but it seems to be plenty to evacuate my laser.

There is no guarantee that this filter is filtering out 100% of the bad fumes, so use it at your own risk. So far, it has worked pretty well for me.

4 People Made This Project!

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52 Discussions

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gtennefoss

Tip 5 months ago

The Honeywell 29500 filters now come a 4 individual "cleanable" filters. They each come with a foam gasket that is used in some applications. There are aftermarket single filters on ebay and amazon. Prices are similar for both the single and stacked filters. I was concerned about loss of air flow because of the loss 3"of filter because of the stack seams but Honeywell must of compensated by adding more folds because their cleaners use pressure switches to test for if a filter needs replacing. They claim these are lifetime filters that never need replacing under normal use. There seems that there is no reduction do the this.

I put a bead of silicon between the filters just to be sure there is a good seal and to keep the stack straight. 2 of the foam gaskets can replace the weather stripping on the top and bottom and may provide a better seal.

I also painted my top and bottom with a couple of coats of gloss to seal the plywood itself to make a better seal and prevent leakage into the plywood itself. This should take care any issues with voids in the plywood layers.

Lastly, if you want a 90 degree inlet, just go to the hardware store and get a 6" adustable elbow in the ventilation section for a few dollars. You can acheive a bend from 0 to 90 degrees just by twisting. You will more than likely need to use silicon or duct tape on the connection points to prevent suction leaks.

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TimJ94

Tip 7 months ago

Activated carbon holds static electricity quite well which means they will try to repel each other. Get it damp to prevent a static charge and thus avoiding a loose carbon bed when packing the filter to make sure the carbon isnt repelling each other while it has a charge. Yes I know its a redundant way of phrasing I just want to make it super clear about the electrostatic repulsion and the easiest way to deal with it.

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patternmusic

1 year ago

I built this laser cutter ventilation filter and wrote up this Instructable for it.

https://www.instructables.com/id/Fume-Coffin-Laser...

It's based on some of the ideas in this Instructable, but it is intended to filter exhaust air for ventilation outside rather than act as an air scrubber filter like this project.

Thanks for the inspiration and great ideas.

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SebastianG142

1 year ago

Hi all

Its great project and I'm planing to build one for my self as well.

As this is 3 years old project all of you have tested it well already hence I have a question regarding the activated carbon.

How long it lasts? How often are you replacing it?

Thanks

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Gerges2001

1 year ago

dear is it prevent smoking that come out while cutting wood ??

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1stage

2 years ago

Great build! I'm going to be building one for the small Chinese K40 laser cutter/engraver I just bought. I got this metal cart from Harbor Freight (http://www.harborfreight.com/24-inch-x-36-inch-steel-service-cart-5770.html), assembled with the top "shelf" upside down, and now I'm going to try to incorporate a fume extractor build into the bottom area of it.

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jack ruby

2 years ago

Hows the smell? Seems like you made this filter a while ago, have you noticed any improvement/degradation over time? Does this filter take care of even stinky acrylic cutting fumes?

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mahsa301

2 years ago

I wanted to know is your filter worked for fume and smell of wood laser cutting?

and

I wanted to know what is the kind of carbon you use to made the filter?

This is an awesome build! If anyone out there doesn't want to go through the trouble of building one, you can check out hydroponics stores; they sell duct fans and carbon filter cylinders for pretty cheap. You can probably find one for cheaper than you could build one, unless you have a lot of the materials already laying around.

2 replies

Those are made to filter smell only - the particulates from the smoke will still get through the carbon only filters.

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There are a ton of filtration options out there, but I knew the configuration used by my old ElectroCorp did the job of filtering acrylic fumes. I did a little searching in the hydroponics realm, but didn't find something that would allow me to do the same pre-filter->HEPA->activated carbon with similar surface area. If you know of a source that does, please post a link.

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ryanstone143

4 years ago on Step 14

Great work, really, but there are so many carbon filtered exhaust kits out there why spend the money or time to build this?
The VenTech IF6CF620 is one (of many) example(s): http://www.amazon.com/VenTech-IF6CF620-Inline-Virgin-Charcoal/dp/B0052ZPMAG
(The cost is $134.75 and it moves 440 CFM.)

3 replies
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Zachryanstone143

Reply 4 years ago on Introduction

I actually looked at that unit, but concluded that there was nowhere near enough filtration with it to remove odors from cutting acrylic.

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ryanstone143Zach

Reply 4 years ago on Introduction

I figured you probably had a good reason not to use a off-the-shelf product! (I'll keep a lookout for any HEPA based units you might be interested in.)

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DaveA12ryanstone143

Reply 3 years ago on Introduction

Those are made to filter smell only - the particulates from the smoke will still get through the carbon only filters.

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prandall1

3 years ago

I really would like to make this for a laser I'm putting on my printer. But I don't have too much money to spend. For now, instead of the fantech fan, could I just hook up my shop vac? Also, for my cnc I have an Oneida Dust Deputy (http://www.amazon.com/gp/aw/d/B002JP315K/ref=mp_s_a_1_1?qid=1439076961&sr=1-1&pi=AC_SX110_SY165_QL70&keywords=dust+deputy); could I hook this system up to that and remove the shop vac? Would this have enough suction?

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JonW3

3 years ago on Introduction

Would you consider posting the vector files for the wood cutouts? I have a big enough laser to cut that.

Also, in an effort to contribute to the thread it looks like Fantech may have upgraded their unit as the CFM rating is now considerably higher than the one from Amazon. I also talked to a FanTech rep and they said not to order them through Amazon as they are not an authorized dealer and they will not support the warranty. That could just be hot air because they are sold through Amazon by distributers. Regardless here is the link to the FanTech FG6XL... http://www.supplyhouse.com/Fantech-FG6XL-FG-Series-Round-Inline-Exhaust-Fan-6-Duct-483-CFM

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makermentor89

3 years ago

Could you please get in contact with me I would like you to services lasercutting devices

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superbenny

3 years ago on Introduction

Hi,
May I ask what wattage your laser cutter is? I'm looking to build this, or tweak the design a little for a DIY laser cutter that I hope to make this year for my final year project and am wondering if it could be made smaller for a say, 25-40W laser cutter. Or how large of a filtering system you might recommend for my requirements.

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Zach

3 years ago on Introduction

With acrylic it really only takes a tiny leak to let the fumes out. I found my motor housing leaked a little as well as between the top two pieces of wood. For me a combination of caulking and some extra foam tape sealed it.