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


  • 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.
<p>Fantastic guide. Exactly what I wanted to build. Works great! Thank you.</p>
<p>dear is it prevent smoking that come out while cutting wood ??</p>
<p>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 &quot;shelf&quot; upside down, and now I'm going to try to incorporate a fume extractor build into the bottom area of it.</p>
<p>Finding this design was the initial step that led me to design my own. I like this system but for my application (vector cutting 1/4&quot; ply wood), I needed something more significant.</p><p>I tested my system with a cigarette and I get ZERO traces of smell. Mine is twice the price in terms of materials to build but I needed a more robust system that will be able to filter smoke / particulates for days on end for our business.</p><p>You can see our free plans at <a href="http://www.gear-nut.com" rel="nofollow"> www.gear-nut.com</a></p><p>You will need to download a free copy of Sketchup to view the file.</p>
<p>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? </p>
<p> I wanted to know is your filter worked for fume and smell of wood laser cutting?</p><p>and </p><p>I wanted to know what is the kind of carbon you use to made the filter?</p>
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.
<p>Those are made to filter smell only - the particulates from the smoke will still get through the carbon only filters. </p>
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-&gt;HEPA-&gt;activated carbon with similar surface area. If you know of a source that does, please post a link.
Great work, really, but there are so many carbon filtered exhaust kits out there why spend the money or time to build this? <br>The VenTech IF6CF620 is one (of many) example(s): http://www.amazon.com/VenTech-IF6CF620-Inline-Virgin-Charcoal/dp/B0052ZPMAG <br>(The cost is $134.75 and it moves 440 CFM.)
I actually looked at that unit, but concluded that there was nowhere near enough filtration with it to remove odors from cutting acrylic. <br> <br>
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.)
<p>Those are made to filter smell only - the particulates from the smoke will still get through the carbon only filters.</p>
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&amp;sr=1-1&amp;pi=AC_SX110_SY165_QL70&amp;keywords=dust+deputy); could I hook this system up to that and remove the shop vac? Would this have enough suction?
<p>i just finished building a slightly modified one, and it works perfectly. i cut six 1&quot; dia circles in 1/4&quot; acrylic and the only &quot;smell&quot; is the freshly cut material itself. i have my extractor unit sitting outside and you can't smell anything. i live in an apartment complex and a neighbor complained about the odor coming from my laser cutter exhaust. this build not only saved me tons of cash (have you SEEN how much they want for a commercial extractor!?!), but my neighbors have one fewer thing to complain to the apartment manager about when it comes to my building/making behavior when it comes to noises and smells. oh, that's the other thing, this extractor unit has &quot;baffled&quot; the sound of my exhaust motor. before it was nearly as loud as the air conditioner, but now you can barely hear it. awesome tutorial.</p>
<p>Great job! I am having a hard time finding an affordable 29500 Honeywell filter. What did you use? I am buying the parts now to build this next week. I am so excited about the prospect of moving my 40w Epilog inside!</p>
<p>thank you :-)</p><p>i used this: </p><p><a href="http://www.amazon.com/Honeywell-24000-Replacement-HEPA-Filter/dp/B00007E7RW/ref=sr_1_1?s=home-garden&ie=UTF8&qid=1437862153&sr=1-1&keywords=honeywell+2400+HEPA+filter" rel="nofollow">http://www.amazon.com/Honeywell-24000-Replacement-...</a></p><p>the 29500 listed above is no longer available. i had to modify the design to accommodate the different dimensions of the filter. i also decided not to attach the fan motor to the extractor. there were a couple other little modifications along the way, but overall, this tutorial is excellent. total cost of this build was just over $300.</p>
<p>I would love any additional details you can give me. I have ordered everything now and will begin as soon as it all arrives. Since you have worked your way through this instructable, any input or advice would be very much appreciated. Why did you separate the fan motor? Can you share pics? How loud is it compared to some other common household item.</p><p>Thanks so much!</p>
<p>feel free to visit my dropbox folder where i uploaded all the images i took while building this. ( <a href="https://www.dropbox.com/sh/rkmygck5f4u4ymw/AADc6ebKm4qcWQeXPhNk7pKVa?dl=0" rel="nofollow"> https://www.dropbox.com/sh/rkmygck5f4u4ymw/AADc6e...</a> )</p><p>the fan doesn't care at what point it's located, beginning, middle, or end, air flow difference is negligible. i'm sure you can &quot;scientifically&quot; calculate differences and say i'm wrong, which i probably am, but in practical use, i haven't noticed enough of a difference to make it worth mentioning, and i've tried it in all three locations. the only reason the fan is where it is happens to be by accident when i discovered it attached nice and neat to the back of my laser cutter without duct tape or clamps. just a simple press-fit and it's nice and snug.</p><p>the sound of the fan was as loud as the air conditioner, but now it's much quieter, despite being inside and the extractor unit being outside. the multiple layers in the filtering have also &quot;baffled&quot; the sound. an added bonus.</p><p>as for advice, i would only say to wait until you have ALL the necessary ingredients and resist the temptation to get a head start. i started with the HEPA filter and traced it out on the 3/4&quot; plywood, then drew circles out from that. the plywood i purchased, since they wouldn't sell me a half-sheet, was two smaller sheets 2ft x 4ft. the actual width is something like 23-1/5 or something, so i made my outer dimensions as large as i could and figured out the channel between the HEPA filter and that outer edge. adding an inch for the &quot;circles&quot; of plywood that hold the hardware cloth and window screen.</p><p>i used this instructable as a guide, i didn't follow it to the letter. another modification was the gasket material. it's a great idea to use the neoprene shelf liner stuff, but neither lowes or home dumper had any, so i used a bead of silicone on the bottom of the HEPA filter and let it dry. in the future when i want to change the filter it won't be adhered to the plywood on the bottom of the unit.</p><p>not really sure how to explain it any better than this tutorial other than to say, take your time, measure twice, cut once. dry-fit your parts to see how they all behave BEFORE gluing or using the silicone caulking. an awl works wonders for starting screws. and resist over tightening the screws into the wood. sometimes a power tool limits our sensation and doing things by hand is better only in that you can &quot;feel&quot; the torque you're applying to the hardware. power tools are faster, but this isn't something you're doing on a production line. speed is less important than accuracy.</p><p>let me know how else i can help :-)</p><p>dw</p>
<p>I got most of the parts and I am cutting today. I just wanted to ask you if feel like you wished you had vertical supports. How snug can you get those wingnuts before things start to crush - or is that not an issue at all?</p><p>Thanks again!</p>
<p>also, my fan goes full blast, no rheostat controller. just plug it in and let it go. it was an added detail i didn't feel this needed. but that's just me. (whispers: it's also cheaper without it)</p>
<p>Thank you so much for your added input. It is fully appreciated!</p>
<p>np.. freely i have received, it's only fair to freely share. good luck and lemme know if you need anything else ;-)</p>
<p>Would you consider posting the vector files for the wood cutouts? I have a big enough laser to cut that.</p><p>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 </p>
Could you please get in contact with me I would like you to services lasercutting devices
<p>Hi,<br>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.</p>
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.
<p>Thanks, that's useful piece of information! I'm off to Lowes to get some 1/4&quot; ply, going to laser cut brand new top (as per &quot;bar2&quot; comment) with tighter motor housing hole. Having thinner top will help motor housing to go deeper into the pre-filter (I might even add small piece of pipe on the inside). And definitely more weather stripping, thanks for the suggestion! Another idea I had is to add some gaffer tape on top 2-3 inches of the outer ring. Carbon seems to settle which leaves empty gap there... Not ready to give up on my $570 investment just yet :)</p>
<p>Just wanted to post an update. Duct tape on top of the inside of the outer ring stopped most of the leaks. I suspect it might have leaked thru holes in the plywood (layers had some gaps) as well as thru less dens layers of carbon. I get just hint of the smell now, so it's not totally gone, but lights years better :) I now realize the circular is probably not the best design idea mainly because carbon compacts toward the bottom, and layers do not saturate evenly... Once I use up HEPA filter I'm going to try and make a box type filter.</p><p>P.S. I measured wind speed generated by the filter, and it's pretty good 210 CFM inside the laser cutter! </p>
<p>Something else worth mentioning. There are apparently different compositions of acrylic which affect smell. I was blaming it on the filter, but last night I tried cutting some 1/8&quot; white acrylic, and to my shock there was NO smell at all in the room! Even freshly cut piece had only faint odor when I smelled it directly! </p>
<p>Great ide,</p><p>Unfortunelly for me we cant get that HEPA filter in sweden, they wont ship it here!</p><p>Do you have any flow data on that HEPA filter and are you running the fan at 392 CFM, can the filter handle that and still be working correctly.</p><p>Anyway great instructable using it for inspiration over here just need to design a solution from the materials I can get over here!</p><p>I have found a pre filter F9 class and HEPA H13 that has capability of 2000 CFM, for a good pricing, and then I will make the carbon filter part my self!</p>
<p>Just finished building one, and it seems to work great! What a great instructable! </p><p>It was hard (especially since I lacked some tools and experience) and took me almost a month to do (weekends mostly). As I mentioned earlier you going to need more than 5 feet of metal wire cloth (just get two packages) and blue post filter is really a must. Also interestingly enough my carbon came in 2 buckets instead of sack (cost shipped was $165). <br>I couldn't figure out a good way to make small 6&quot; hole on top (router jig doesn't work for such small diameter) so I drilled it out and then used router to cut it freehand. It came out pretty bad, so I had to use a lot of calk to seal gaps near the fan base. Also since I didn't have plunge router, I managed to do all cuts with fixed router, it just took longer (do it outside if you can, and watch out for wood dust getting set on fire! I almost started one). At first I didn't think I need casters (since it will be placed on carpet) but I glad I did add them, as this extractor is EXTREMELY heavy.</p>
<p>Awesome! Looks great. </p>
<p>It seems that I jumped the gun when I said it works great. Now that I finally had a chance to cut acrylic I must say, it maybe filters out 50% of the smell, rest goes straight thru all the filters and carbon and it stinks, really stinks :( I checked and double-checked, there are no leaks. Smell is coming near top layer of carbon. I opened top cover, topped off carbon, shook it added some more until it was even with all sides, closed tightly and... nope fumes are still getting thru :(</p>
<p>I'm 98% done with the build! :)</p><p>It probably depends on screen mesh size, but I'll tell you folks, that post filter is NOT OPTIONAL as I found out the hard way ... As soon as I switched fan on, it started to snow fine carbon particles :O</p>
<p>Quick question. In the supplies you list both two 3M foam filters and Duck brand filter. But it's unclear if Duck Brand one is every used for anything?</p>
<p>bratan - In step 9 I used both... Duck filter on the inside of the mesh cylinder and both 3M filters on the outside.</p>
<p>Thanks I see that you added description of filter now! :) </p><p>I'm in final stage of the build, it's coming out great. </p><p>One more thing I wanted to mention is that one roll of wire cloth is simply not enough. I was about 5 inch short on the outer ring, but fortunately I had just enough size piece left from inner ring so I patched it up. However I had none left for the pre-filter. If you did manage to construct all 3 pieces from same 5 foot roll of wire cloth, you must have got an extra length in the package somehow...</p><p>Once again this instructable is simply EPIC, I can't wait to finish up my build and post some pictures.</p>
<p>Very very impressive! I'm going to make one after I get laser cutter. Thank you so much for instructions!</p><p>I'm curious have you considered an external enclosure for it? Maybe some kind metal with lots of holes rolled into a cylinder... :)</p>
<p>I haven't needed that, but if you build one, please post a picture of it </p>
<p>How many times can you replace the carbon with a 55lb bag?</p><p>I am planning on building one of these. Great project, I live with neighbors close by and still plan to exhaust outside by adding another other container which would then duct outside.</p>
<p>You can fill it twice with a 55lb bag.</p>
<p>This is awesome. I have been looking for a fume filtration for my laser, and this fits the bill perfectly. I definitely plan on making one. I do have a question.</p><p>How is the blower attached to the filtration system? Is it just set there? Or is there something securing it in place?</p><p>- Ton</p>
<p>Hi Ton - I cut the hole so that it would basically be a press fit. I've fixed the few minor leaks with silicone caulking. Guess that could also hold the blower in place if your hole was a little large.</p>
<p>Perfect. It seemed like it was just a pressure fit, but wanted to confirm. Out of curiosity, how far a run are you making with the hose? Are you using a reducer when it reaches the laser cutter (unless you have a 6&quot; exhaust on your laser). Also, did you use the entire 55 pound of charcoal in the unit?</p><p>I also have a small airbrushing booth, where I spray water based paint. I think I will make a manifold, so I can also extract fumes from there. </p><p>This is a great tutorial, cant wait to build it.</p>
<p>Made one and it works great! </p><p>You can use your laser cutter to make the top and bottom pieces if you split them into multiple sections. I've attached the .DXF file, they are intended to be cut from 1/4 inch wood, then stacked two layers thick to make 1/2 inch. The top and bottom layers should be rotated or flipped so that the joints do not line up.</p><p>Thanks for the project!</p>
<p>thanks. today start construction. good luck for me and amazing work friend Zach</p>
<p>tanks </p>
With the carbon being the final step, what prevents the fine carbon dust from blowing all over your shop? Also I'm surprised you didn't pirate some parts off your old extractor, namely the blower and speed control.
Ha! I had the same thought, which is why I turned it on the first time outside. I imagined a cloud of black dust, however, there just wasn't much dust at all. However, adding a final layer of filter mesh on the outside to catch any stray dust is probably not a bad idea. The original ElectroCorp had this.

About This Instructable




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