My hope was to get the updated 20BIN Gridfinity Case posted this week, and also maybe add some minor changes to the 25 bin and maybe (maybe) the 16 bin versions as well.  The changes are not a big deal really, but they need to get done, so I can set that project aside for a bit and get some other stuff done.  However I recently saw a video about CR filters and an idea popped into my mind.  I had seen that Costco has some MERV14 3M filters on sale (20x25x1), and I also found a deal on some 120mm case fans which have S-FDB bearings, which should run quiet... 

What started off as some CAD "doodling" ended up as another potential project, and it's a big one too.  The idea is to try a 5x120mm 12V fan design, with two filters, so I could either build another one, or keep the other two filters in the 4 pack as spares.  I don't know how many days this will take to print, since I have not completed the design yet, but it's gett'in close to being done.  I may just set this one aside if the filament cost is too high though, since prototyping large projects sucks when they don't work out (and is costly too).  The design is gonna require steel dowel pins to assemble the eight or so major components (a technique that I used on my enclosure, and has held up really well).  I should know in a week if this project will be attempted or not.

Update 5/29/2024: I did some more work on the design, pretty much just tying to have fun with it, and filled out a few of the more technical parts as well.  I'm leaning towards making this project, and ordered some of the hardware from AliExpress (which I can still use on other projects if this one falls through).  A hex pattern was added to the top, which I hope may help conceal some of the lines between the parts.  The renders always look better than real life though.

Update 5/31/2024:  It looks like this project's Rubicon has been crossed, since I put down the 40 bucks for some 3M filters.  I'm honestly not looking forward to printing the prototype for this, since if it fails I will be out a lot of material.  I'm gonna work on trimming the print time down though, and will need to cut out some sections to test them first.  I'm gonna wait for the steel dowel pins from AliExpress before I consider printing the whole deal, since those will be important to test before going all in on printing the design.  

Update 6/4/2024: I think I have all the bugs worked out, and have tested about 20 designs to make sure the 3mm steel dowel pins fit just right.  I'm starting to print this thing today, but it's gonna be a 16 plate print, so I expect it will take a week or so to get everything done.

Update 6/7/2024: I printed a few parts, specifically the lower front and middle (2nd row from the bottom, first and second parts from the left in the image above).  Unfortunately both will end up in a landfill, but I still feel lucky to have caught a couple problems before I went all in on printing this thing.  I did a significant amount of work to correct the issues, and I also to added a channel for a strip of felt around the filters, which will help to seal the filters from air leaks.  I'm gonna try some 22mm felt, but the channel should be able to hold 1 inch (25.4mm), between 2-3mm thick. 

I also added some quality of life improvements, which I think may make assembly a bit more straightforward.  I'm pretty sure I got the bugs worked out now (though that's what I thought last time LOL).  Still I'm gonna take this one slow, until I'm sure, so I don't waste material.

​Update 6/15/2024: My test prints ended up just as I had hoped they wouldn't.  I budgeted 4 spools (and change) for this and it will end up eating up 6-7.  Some of it was my fault, since I decided to thicken up parts of the design and add a groove for an optional screen which could protect the filters after I had printed a couple of test pieces.  Unfortunately I don't plan to buy the screens now, since the materials budget is blown on this project.  The other part of my filament woes are thanks to the PLA I am using (Duramic3D).  It has been one of my go-to brands, and it prints very well, however in this one project, I've had two tangle failures on two different spools of their white PLA.  Those failures cost me a half a spool in lost material, and a print defect on another large part.  I've not had tangles with even cheap $8 spools of no name stuff recently, so something must be up.  I won't write off Duramic3D completely yet though, since the last several spools of their Gray PLA have been flawless - I also need to buy at least one more spool of their white PLA to finish this project.  It sucks though, and just adds to the cost of an already expensive side project.

The pics below make it look a bit loose, but that's because it is just sort'a put together right now without glue, so the joints are not tight.  It looks like the filters fit though, and I have no big red flags currently to worry about, except that I'm out of PLA lol.

And just as I finish writing this, there was a 3rd tangle (2nd on this spool)...fortunately I can see the end of the spool, so maybe the next one will be better.

Update 6/17/2024: The parts are almost done printing, so I started the assembly using the 3mm steel dowel pins and some medium velocity superglue.  The dowels are an extra item, but they are cheap and add a lot of strength to the parts.  I used the down pins in my enclosure project (for the doors), and when used with a tight fitting joint and superglue, the glued up parts end up very strong.  Everything is fitting as planned for the major parts of this project, but I did hit one snag.  The fan controller which I purchased does not fully turn off the fan.  I should have guessed this, but oh well.   Fortunately I have a spare that will work, and shuts off the fans completely.  But using the new controller requires a minor change, which will only require reprinting a small part.  The change of controller also forced me to pick up a fan hub, since the new PWM board has only one port.  While I was buying stuff, I picked up some 4 wire fan extensions and some ramen. 

I also did some testing of the 12v LED ring light, which will backlight the control knob, and it works pretty well.  Using a 1k Ohm potentiometer, I found that 100 Ohm gave it just enough brightness, so I wired in a 100 Ohm resistor in series with the ground connection to the LED ring.  I plan to connect this to a spare fan header, so the LED will go off with the fans (though it is not PWM controlled).  So it's getting close, but still not done yet.

Update 6/18/2024: This project is in the home stretch, but damn it's had problem after problem.  I blew through almost 2 spools in failed parts due to tangles, or parts that I decided to re-work after they had been printed.  Then when I had everything together, and tried it for the first time... nothing.  I was able to get it working after reconnecting all the wires, but then I found that the LED was not working.  The LED turned out to be a broken solder joint, which was an easy fix.  The solder pads on the ring LED are tiny and fragile though, so I added some glue to the wires around it. 

After getting the prototype together, I found a few issues which I had to resolve in the final model.  The biggest problem was that I didn't plan to use a fan hub initially (the board I was going to use had fan headers on it), so there was no good place to mount a hub.  I think a fan hub is a good way to go in hindsight though, since it allows for using a cheap and compact PWM controller.  So I updated the model with a small enclosure for the fan hub, and a cover to conceal the wires, which in my prototype are just sort'a a mess.  I did my best to zip tie the heck out of the loose wires though, and there are none that could interfere with the fans, so it's really just cosmetic.  I'm printing the last two grills now, but overall I'm really happy with this filter.  It is super quiet and should only draw around 12W (though I have not measured it).  The 5 fans together put out a decent amount of air, and I can feel some flow through the filter, but I don't know how well it will work yet.  Time will tell.

Updated 6/19/2024: It's completed (finally).  I'm really liking how quiet this thing is.  It is not not the cheapest air filter, but I think it fits a niche, just like other CR filters.  The cost breakdown was as follows:

1. 3M 2500 Series Filtrete 1" Filter, 20x25x1 4-pack ($40 on sale at Costco - now back to $60)
2. Thermalright Fan HUB Controller REV. A ($6 at Amazon)
3. 0.87in Furniture Pads Roll, 6.56ft x 2 Rolls Self Adhesive Felt Strips ($9 at Amazon - and it needs one more roll for 3 total rolls)
4. (qty 2) Thermalright TL-C12C X3 CPU Fan 120mm Case Cooler Fan, 4pin PWM Silent Computer Fan with S-FDB Bearing ($24 at Amazon) - This is for 6 total fans, but I only need 5 for this project
5. Fan Splitter, 3 Pack 4 Pin ($8 at Amazon - though much cheaper on AliExpress)
6. PWM Fan Extension Cable 12.2 Inch ($7 at Amazon - though much cheaper on AliExpress)
7. 12V DC Manual 4 Wires PWM Fan Speed Controller with On Off Switch ($10 at Amazon - or about $4 at AliExpress)
8. I also used a DC power jack and a fuse holder (which I am using a 2A fuse with) which I have in my spares.  Those would be aroud $15 at Amazon or maybe $5 at AliExpress.
9. M3x30mm steel dowel pins (I paid $10 for 60 of them at AliExpress, similar at Amazon would run $15)
10. 28 Grams 750 CPS Super Glue ($7 at Amazon)

I did not use them, but the final design will have holes to mount some rubber feet such as these:

Cutting Board Feet, 8-Pack Non-Slip Soft Rubber Feet Bumpers Kit ($7 at Amazon)

The design can also use some screens to help protect the filters, though I did not use those.  They would add about $22 and would need to be cut to size.

Add to that all the filament (which I need to calculate), but I estimate probably 4 spools worth of the stuff in White (3 spools), Gray (1 Spool), Blue (maybe 100g) and clear (less than 100g).  In my case however, it was more than 6 spools since I had a big failure on one spool, and also reprinted a few pieces after design changes.

So my total cost was around $160, plus a few small parts I had on hand.  I could have trimmed off about $15 of that by just hard wiring the fans instead of using splitters and jumpers, but I don't enjoy soldering and still had to do some of that with this project.  It's probably better to just buy a filter for much less, since this is not HEPA (its MERV14), but it is super quiet, draws very low power, and I think will help clean the air in conjunction with a HEPA. I also think it looks cool.

Update 6/20/2024: I came across some high static pressure fans, which I think would be ideal for this design, if I make another one.  The Arctic P12 Max 120mm fan (corrected link) has a static pressure of 4.35 mm H₂O, which seems to be legit.  That is compared to the 1.53 mm H₂O static pressure of the fans I used (Thermalright TL-C12C X3).  The Thermalright fans are very quiet though, while the Arctic P12 Max fans will be louder, and about $20 more in cost overall.  I can feel air moving through the filters with the Thernalright fans, so I think they will do the job, but I'd still like to try the Arctic P12 Max fans (if I build another of these).

Update 7/10/2024: I've been waiting for the Arctic P12 Max 120mm 5 pack of fans to come back in stock, but so far it seems hit or miss (more miss).  There was a period where one Amazon reseller had the 5 pack, but I didn't pick them up since I didn't know at the time that the reseller was an authorized dealer (and I generally don't like to buy from 3rd party sellers on Amazon).  I planned to buy them from the Arctic store on Amazon, but they've not had them in stock for as long as I've been checking.  I'm gonna wait a bit longer, and see if the 5 pack comes back. 

I don't plan to post this project until I find (and test) some good fans to recommend with it, since the Thermalright TL-C12C X3 fans I'm using are just barely adequate (though they are very quiet).  With the CR type filters, it's probably more like a marathon than a sprint anyway, but I would like the ability to crank up the fans and move some air when necessary, even if a lower speed would be used normally.

Update 7/16/2024:  Well, I missed the boat on getting a 5 pack of the Arctic P12 Max fans, they seem to be gone.  The single P12 Max fans are also not an option, having increased in price quite a bit in the past couple weeks (they are now at $17 after hovering around $10 recently).  The P12 Max fans may have been shooting for the moon on a simple CR filter like this, where quiet operation is important, though it would have been nice to have tried them.

However, while I was looking at the Prime Day deals today, the be quiet! Pure Wings 3 120mm PWM High-Speed Case Fan (BL106) caught my eye at only $7.70 each (on sale).  It's a significantly less powerful fan than the Arctic P12 Max, but also should be quieter.  And they claim a lifetime of 80,000 hours (with good reviews as well).  The be quite! fans should have about twice the static pressure of the fans I am currently running (which do the job just OK), and the reviews say it really is quiet, so I am hopeful.

I will update when I get the fans swapped over, and test it out.  Shipping will be slow on these though, I expect them in about 2 weeks.

Update 7/31/2024:  The be quiet! Pure Wings 3 120mm PWM High-Speed Case Fan (BL106) arrived, but I have not had time to swap them in place of the Thermalright TL-C12C X3 fans I'm currently using.  I hope to get that done soon and will update here on how I perceive their performance.  Unfortunately I don't have the skills or equipment to really test the performance with the filters, so it will all be subjective.

Update 8/4/2024:  I installed all 5 of the new be quiet! Pure Wings 3 120mm PWM High-Speed Case Fan (BL106) and it really seems like a minor improvement over the Thermalright fans, if any.  I can tell the fans are pushing air through the filters, but I'm not sure how effective the filter is with only 5 120mm fans.  When I checked the filters after running for a month, they still look pretty new on the inside, but the air where the filter is located is pretty clean to begin with.  I did see a frosting of dust on the old Thermalright TL-C12C X3 fans though, which could mean the dust in the filters is not gonna be easily seen yet.  I suspect that the Arctic P12 Max fans would have been a better fit for this project, but I'm pretty tapped out with buying fans for this project, and the 5 packs for those fans appears to be gone from Amazon.  I'm gonna move it into a room where there may be more dust to see how the filters do, in case I did not give it a fair test.  I'm also considering doubling up the fans, however I need to google around a bit, to see if that is gonna negatively affect their performance or lifespans.  This project is likely not gonna be posted without a decent high pressure fan solution, which I can recommend for builders.

There were a few comments on the Gridfinity 1x2 Watch case, noting that it does not fit large watches well, specifically watches with a crown which sticks out at 3 o'clock.  To hopefully address this, I'm updating the watch case with a wider single 1x2, and a 3x2 version, which will both accommodate larger watches.  These cases are really only for pretty simple storage though, since there is nothing that secures the watch holders in the case, aside from magnets.  I'm considering making the inside top flat, since the grids on the lid don't do anything.  A flat area on the inside of the lid may be nice place to add some felt too, or maybe attach a TPU liner...  I hope to get these completed this week and uploaded.

Update 5/16/2024:  I cleared the grids from the lid of the case, and designed a TPU insert that can go into the top, to provide some protection for the watches.  The TPU liner has some notches which will hopefully lock it in place, so no glue should be needed.

Update 5/17/2024: I printed the base of the 3x case, and found that the watch holders are a bit loose.  To address that, I added some taller curbs in the base for the watch "bins", and added some taller walls to the watch "bins" as well.  The idea is to make a more stable base for the watch bins to sit in the base of the case.  I think magnets would also help, but I did not install those yet.  It's a bit hard to explain, but I will post some pics later.  The rest of the case is still printing, so I should have an update on it tomorrow.

Update 2 5/17/2024:  Unfortunately my printer has experienced three clogs on the same Polymaker PolyLite Galaxy Blue PLA, which has been printing fine previously (and looks great).  I'm using (and have been using) a 0.4mm nozzle, and have printed maybe 15% of the spool so far, and the results up till now have been great.  After clearing the first clog, I switched to a plain gray PLA and ran a 2 hour print with zero problems.  But when I switched back to the Galaxy Blue, it clogged after several dozen layers.  The 2nd clog resulted in having to swap the hot end (for another 0.4mm), since it was not clearing out using all the normal tricks.  After the 2nd 0.4mm nozzle clogged, I decided (after clearing that clog) to use the big hammer, and swapped in a 0.6mm nozzle.  The larger nozzle should have been my first move though, since it knocks a good chunk of printing time off these cases, and most of my stuff lately has been larger designs.

I went over the other changes I made, since I previously ran several successful large prints with the material.  One change was that I updated Bambu Studio to 1.9.1.66.  More significantly though, I noticed that the infill was set to 3D honeycomb, which I don't use normally, but possibly I forgot that I changed it.  I normally use rectilinear, which I use since it does not cross over itself, and also works well when combining infill to speed up print time.  IIRC, 3D honeycomb is a pattern which has to cross over itself, which may have contributed to the problems, but seems like a long shot.  In any case, I changed the infill back to rectilinear (12%), with infill combination, and swapped in a 0.6mm nozzle.  Hopefully that will solve the problems with this (really cool looking) Galaxy Blue PLA, since I would hate to have to write off the spool due to clogging.  

Update 5/18/2024: The changes worked, and the top is printed, so testing is back on track.

Update 5/19/2024: Everything is printed and the parts fit well.  The TPU insert in the lid snaps in place and keeps the watches from knocking around, even when I rolled the case around, but it does not interfere with opening or closing.  The only change from the prototype pictured, and the final design, is that the final will have taller bin separators in the base of the case (which can be seen in the last pic).  These separators work with the taller sides of the watch holder "bins", to help keep the watches and holders from moving side to side.  Even the shorter separators on the prototype base work to reduce the sideways movement. 

The 3MF profile is also completed, so this will be uploaded later today.

Update 2: The single and triple watch cases have been uploaded, along with the 1x2 Gridfinity Watch Stand:

MakerWorld (downloading here helps me out with points)
1x2 (Single) Watch Case
3x2 (Triple) Watch Case
1x2 Gridfinity Watch Stand (compatible with both designs)

Printables:
1x2 (Single) Watch Case
3x2 (Triple) Watch Case
1x2 Gridfinity Watch Stand (compatible with both designs)

​
I have been using the CC BY-NC-SA license for most of my models (aside from remixes which require other licenses), since I have been posting stuff (several years now).  However with this model, I'm trying out the "Standard Digital License".  The Standard Digital License has much tighter terms, and does not allow remixing, redistribution or commercial use.  I may move to this license for more designs in the future, since it avoids any question of having my stuff redistributed on other platforms, which I did not intend for and cannot maintain.  Whether it's OK to redistribute someone else's work on other platforms under the CC licenses, I'm not 100% certain of, though it does seem so, even though it's not ethical to do (and I think most reputable 3D model archives frown on taking from designers that way).  The Standard Digital License may also tighten up the CC commercial use restrictions, which have been ignored on some designs in the past by Amazon and AliExpress sellers (so it may not do much good changing anyway).  

The one thing that I don't like about the Standard Digital License, is that it has no provision for remixing.  I am a big fan of remixing, so that could be one reason I will opt instead for a CC license on some designs.  Remixing seems to be an all or nothing deal with my models though, with some designs getting dozens of remixes, and others with zero.  If I do use the more restrictive Standard Digital License more often, I will use it sparingly, for models which represent a considerable time investment, and where I want to maintain some control over the way the design is redistributed.    

I've been working on some small updates to current designs, as well as a fix to the 16 Bin (6U) Gridfinity Box For Stuff.  First, the fix was to repair a problem with a through hole that was not a through hole in the model of the 16Bin case.  This hole is where the handle screws into the base of the case, and is now fixed at both Printables and MakerWorld.  There was a glitch with the 3mf profile on MakerWorld, which did not get fixed until today.  Thanks to user_2916867828 (at MakerWorld) for letting me know about the problem. 

The other updates relate to the gaskets for the 1x2, 4x5 and 5x5 Gridfinity Boxes for Stuff.  When I was working on the 1x2 Gridfinity Watch case, I decided to make the gasket wider, since the stock gasket size seemed thin.  The wider gasket fit well and was easier to install, so I thought it would be worth updating the existing models to use it.  The pic below shows the difference, with the new wider gasket on the left and the thinner (current version) gasket on the right.  

I don't know if this will help with the water resistance, but I think it looks better and probably makes a better "seal" - though the gaskets are not water tight - since there are too many factors that go into that.

The gasket is also going to be a few mm thicker, since it was suggested on Reddit that possibly some hollow space would add some squish (and make for a better seal).  I think the only way to make the seal more water resistant, is to use a more compliant TPU, or cast it in silicone, but those are both expensive and messy options.  

The 1x2 gasket is the same as what I used on the watch case, so I don't need to test that one.  I plan to test print the 4x5 20 Bin version, before posting it, but I don't think I will test the 5x5 version, since I have no use currently for that size (if it is posted there will be a notice that it is untested).  The changes to the gasket design will not modify the outside dimensions of any of the boxes, and are pretty minor updates, however the current versions of the base and top will not be compatible with the newer versions with the larger seals.  I will post on this blog when the updated designs are uploaded.

Update 5/6/2024: The new larger TPU gasket design for the 20Bin (4x5) Box For Stuff is done now, but I still need to give it a test and then prep the files to be uploaded.  This design is identical to the existing version, aside from the new gasket design.  The improved gasket is also easier to install.  The middle pic shows the new version in white on the left, and the old version in black on the right.  When the models are updated on MakerWorld and Printables, I will post a link here.

Update 5/14/2024: Thanks to some really helpful feedback from a user over on Printables, who is making the 5x5 version of the case, using a large nozzle and large layers, I may make another small update to the design which I'm working on.  I've been printing these using a 0.4mm nozzle, and a baseline 0.2mm layer height, which is not fast for such a large project.  The upside of using that standard resolution, is that it allows for everything to fit well, and I have not had a problem yet with the many prototypes I've printed using those settings.  Using thicker layers and larger nozzles saves time, but consequently means lower resolution, and possible smaller clearances than designed, due to slicing tolerance.  There are other possible issues such as flow or k-value calibration, which can directly lead to problems with fit as well, but those are not something I can design around.  But I may be able to add some tiny extra amount of slop to the design, to help folks using large nozzles, so I'm gonna make a small change to the design.  Specifically, I'm gonna widen out the inside to give 0.75mm clearance around the bins, vs the approx 0.5mm clearance currently.  The pics below show the current design with 0.493mm of clearance at the bottom of the case, which tapers up to 0.75mm at the top.  I will probably just make it 0.75mm all the way to the bottom, and remove the taper.

I think that once that change is done, the updated cases will be ready to be uploaded.  I may release the 5x5 (25bin) first though, since I think somebody is waiting for the update and then I will probably run yet another 20bin to test and then upload that version later.  The changes are pretty minor, and include the following:

• Thicker and wider gasket which is also easier to install
• Adding an additional 0.25mm clearance around the outside perimeter of the bins on the inside of the case

Update 6/15/2024:  The 25Bin case has been updated to the new v2.3 design, and the 20Bin case should be posted very soon (I only have to test one more part).  The only significant change is to the gasket, which is much thicker now.  I also plan to provide a mold for making a silicone gasket, however I have not been able to test that idea yet.

20 Bin Gridfinity Box For Stuff v2.3 on MakerWorld and Printables (uploaded 6/29/2024)

25 Bin Gridfinity Box For Stuff v2.3 at Printables