A Strategy for Obtaining Great Prints

Like all new endeavors, there IS a learning curve with 3D printing. This is still the pioneering era for desktop printing and we are very fortunate to have such a great community here as well as other resources on the web. But the challenge with all the information out there is finding it when YOU need it and deciphering the many different opinions and practices - some of which are good and some of which are, well, let’s just say “poppycock”.

Another part of the challenge is there are many different means to the same end, but I assert that those who have developed a workable (AND reproducible) technique most likely took a disciplined approach rather than the shotgun approach of trying one thing after another. So, I thought it would be helpful to describe a method that you can use to 1) develop a reproducible approach to successfully printing the things you want and 2) improving the quality of your prints to meet your (realistic) expectations. Don’t hesitate to join in or ask questions. As required, I’ll consolidate any interesting information from follow-on posts into this initial post to help make everything easy to find.

Ready to go? Before we do, here is a little suggestion.

TIP: When you are starting a new print session, give the printer a little warm up exercise! Much like an athlete needs to warm up before a game, so does your printer! Don’t just turn the printer on and start to print, turn it on and let the hot end get up to equilibrium, let the heated bed get up to temperature. I even like to print a quick part to make sure everything is up to temp, in equilibrium and working properly. It’s quick and easy to do and can help eliminate a lot of problems.

#1 Get Experience. Start with the printer. This is more difficult than it seems because without experience, it is hard to know if you have a mechanical or electrical issue, slicing issue or if something else is going on. So, to that end, keep things simple until you have some experience. By “simple” I mean, don’t print the Eiffel Tower model for your first print, print a simple, reproducible and small item many, Many, MANY times until you nail it. For me, I used the calibration cube. In retrospect, I should have picked something much simpler (see strategy #2).

#2 Start Simple. We have a tendency to want to jump ahead to more complicated prints, faster printing, and bigger prints as quickly as possible. But a few hours spent working on a simple object or two will pay dividends. There are many aspects to successful 3D printing, everything from the printer (which in itself has a mechanical system, electronics system, hot end, extruder, heated bed, firmware), to the slicer (and all of the parameters available to control the slicing), to the filament itself, to the actual item being printed. With so many variables (100s, maybe 1000s of them) it is really important to pin down as many of them as you can. One very easy place to do this is with the model itself. Develop your experience printing the same model over and over until you nail it. Even with a simple model, you can (and should) approach printing it with a methodical approach from the ground up. That’s the next strategy.

#3 Practice in Measures. I play guitar and was basically self taught. When I found new music to learn, I did what many untrained folks do and practiced the piece over and over again from beginning to end. If I made a mistake, I started over. Then, I took lessons from a trained musician. My very first lesson was worth every penny! My instructor watched me learn a piece and then said “you should Practice in Measures”. What he meant by this was to learn the first measure (music is divided into small blocks of notes called measures which are small and relatively simple). Practice it until it is perfect. Then, practice the second measure until it’s perfect. Next, combine the first and second measures until that is perfect. Continue in this way until you’ve learned all the measures and combinations of them. In complex pieces, there will be a few measures or sequences of measures where you need to put in a lot more practice.

The advantage of this approach, my instructor said, is that you are not wasting lots of time playing measures you already know. The practice of playing from the start until you reach a difficult spot and make a mistake is that you play, say, 30 seconds (or more) of music you already know to hit a 1 second spot you need to practice. So in a 30 minute practice session you are really only practicing what you need to practice for 1 minute! This completely changed my approach to practicing everything from guitar to 3D printing to machining to learning CAD, to …

How does this apply to 3D printing? Easily! Start with a simple object to print and practice nailing the first layer. Too often folks will print a poor first layer and allow the print to continue. Why print on a bad foundation? You might be able to salvage the part but more times than not, it will peel from the bed or warp badly. Instead, nail that first layer. Once you have that perfected, move on to print the rest of the object. Once you have the entire object printed successfully, change slicing parameters to print faster, or at higher resolution and start over (nail the first layer, …). Practice in measures.

I can’t say enough about getting that first layer right, the subject of the next strategy.

#4 Nail the First Layer. I don’t believe folks spend enough time learning to print a perfect first layer reliably. If there are defects in the first layer, they will invariably come back later to bite you later - the part separating form the build plate, warping, or a defect in the part. Print a good (or great) first layer is probably one of the most frustrating experiences for most, it is also the most critical. Here’s where strategy #3 comes to play, don’t continue a print on an inferior first layer! Abort the print and restart that first layer again and again until you nail it. Why waste time on a part that will most likely fail or not be useful? Each time you print a first layer, measure it! If you configure your slicer to print a 0.20mm first layer, then it should be pretty darn close to 0.20mm. If it isn’t, you’ve identified a variable that you can easily fix and nail down (Z height). 0.20mm is not a lot and unless you have highly calibrated eyes, you can’t tell the difference between 0.20 and 0.15mm, but your printer sure can. At 0.15mm the first layer is going to squish onto the print surface. It may even seem like you are getting a great first layer and great sticking (which you are) but later, you’ll discover the part is nearly impossible to remove or your extruder will start making that all too familiar TICK, TICK, TICK sound from missing steps. A perfect first layer will go down smooth and consistently time after time.

TIP: polish the tip of your nozzle! Chared filament and scratches on the very tip of the nozzle are dragged over the layer as it moves around. Best case, these leave a visible mark on the print; worse case, they rip the first (or higher) layer off the build plate.

#5 Slow Down. Back to my guitar lesson example… The other thing my instructor taught me in that first lesson was to practice slowly (using a metronome) until I nailed the measure(s) at a slow tempo. Then, gradually and consistently, increase the speed. The same applies to 3D printing, print slowly at first. This gives you time to observe what’s going on (strategy #6) and just simplifies everything. I like to start new folks at 20 to 25mm/s print speeds. What’s the hurry? If you print 10 aborted prints at 50mm/s what have you gained (or lost)? Printing slow helps all parts of the printer, from the mechanics to the extruder to the plastic filament coming out the nozzle, stay in balance or equilibrium. Fast movements can highlight mechanical issues, extrusion issues, etc. But when you are first starting out, you don’t know how to identify and isolate these issues. In fact, even with all of my experience, if something starts to go wrong, I slow down. That removes a lot of variables and gives me a chance to see what’s happening. I’ve identified everything from loose pulleys, to a stretch belt, to a worn joint on a delta printer arm! And, I’ve helped a lot of folks identify other issues simply by slowing down.

#6 Watch What’s Happening. Especially in the early stages of learning, watch all aspects of the printer. Combined with strategy #5 you’ll start to develop an appreciation for how the slicer does its magic, how the printer does its magic, and it is just simply fun to watch! I highly recommend putting a flag of some type on your extruder motor shaft so you can actually watch retracts and advances and watch the steady push of the filament. A piece of masking tape stuck to the shaft is fine or print one of the pointer models. Watch that first layer print, that’s how you’ll see if there is a problem and maybe even figure out why. For example, I noticed that the first layer wasn’t sticking in the same spot on my build plate. Turns out that I had some potato chip grease there (don’t ask)! A little wipe with isopropyl alcohol and I was back in business. Watch what happens when the layer fan comes on. Is it coming on too early and causing the part to peal from the print surface? Pay attention to the details of what’s going on and then…

#7 Keep Notes. I can’t stress how important it is to keep notes. I have a word processor file I add notes to as I go. In particular, I keep a section on the filaments I use and the detailed printing parameters for them (strategy #9). Perhaps I’m becoming forgetful in my advanced age but I don’t like solving the same problem over and over again. If I keep a note about a problem and my solution, I can usually find it again pretty quickly. Once comment on notes, don’t be afraid to purge! After a few years of doing this, my file got quite big. Recently I archived all of my H1 and H1-1 notes. I don’t refer to them any longer so why keep them in my working notes?

#8 Be Consistent. A CEO friend I worked with many years ago was fond of saying “Consistency is the hobgoblin of small minds!”. I understood what he was trying to say but it has to be taken into context. When you are first learning any new activity, it is critical to be consistent. If too many things are changing at once, you have no idea what contributed to a good or bad result. Don’t change too many things at once. In fact, if you can isolate and change just ONE thing, you will have a much better chance of success and understanding. This isn’t always possible so lock down as many things as you can. If after a run of successful printing you run into a problem, go back to a known good state (see #7 - you did keep notes on what this state was didn’t you?) and start there. Many times we try to change too many things in our frustration and that almost always makes things worse. Step back and think about how to isolate the problem areas with as few changes as possible.

#9 Know Your Filament. This strategy is a little lower level than the previous eight but important and often overlooked. I see a lot of folks just assume that they should print filament X at temperature Z - for instance, print PLA at 200°C. This might get you in the ball park but if you really want to get consistent and GREAT results, profile your filament. It’s easy and if you write it down (see #7) you’ll never second guess how best to print that filament again. It’s important to realize that higher temperatures are not always better, they can actually lead to issues - parts that are just a little too large, parts that stick to the bed too well and can’t be removed, blobs on the print, stringing, and a host of other problems. In general, I like to print at the lowest temperature possible for PLA and ABS. Then, as I ramp up print speed, I also need to ramp up the hot end temp a little since the filament is not resident in the hot zone for as much time. I suspect little details like this cause people more problems than they might anticipate.

Here’s how I profile a new filament:

  • Start with a reasonable target temperature - 200°C for PLA and 225°C for ABS (one quick note, it is ideal to have a calibrated hot end, so when I say 200°C I mean 200°C. One easy way to do this is to make a little table with the hot end set temperature (what you see on the temp display) and the measured temperature (with a thermocouple). Do this in 5°C increments from 160° to 240° C (or so). Keep this chart in your notes (#7) and you will always know what the actual temperature is.)
  • Now, use the manual controls of your host to extrude 50mm at 50mm/s and watch and listen.
  • If the filament extrudes nicely, reduce the temperature by 5°C and wait for the temperature to stabilize.
  • Test again by extruding 50mm at 50mm/s
  • Repeat until you reach a temperature where the filament does not extrude well. At 5°C to that temperature and note this as the “low extrusion temperature” for that filament. Use this low temperature whenever you are printing slowly (20-30mm/s). You might find some filament need to be bumped up a bit more than 5° so don’t hesitate to experiment and find that lowest reliable extrusion temperature.

If you want to get really serious about profiling your filaments, do the melt-flow test at higher extrusion rates - 60 mm/s, then 70mm/s, etc.

Don’t forget to measure the diameter of your filament too! Not all filaments are created equally. Measure in several locations to get a sense of variability. Most of the slicers let you enter filament diameter and they will calculate a reasonable flow for you.

Finally, once you’ve completed the filament profile, print the Simple Single Layer Test object in the Layer Tuning section at the end of this post.

#10 Know Your Bedfellows. Probably one of the greatest mysteries in 3D printing is “the bed”. Metaphorically, this is where the rubber (filament) meets the road (bed) and getting “it” right is absolutely critical to successful fused filament 3D printing. All sorts of folklore on bed materials, coatings, coverings, concoctions, and juju exists here and elsewhere on the internet. It is also one of the areas that there is no one right way to do it. If you have discovered a special incantation and bed preparation that works, by all means stick with it! But, for those of you struggling, here are some strategies you can use to make improvements. One comment before I begin…

I am VERY persnickety about the aesthetics of my 3D prints. My 3D printed fly fishing reel is seen from all sides and so it is important that the first layer is flawless and visually appealing. The photo below is the bottom surface (first layer) in both the outer teal ring and the inner white spool plate (you can see more of my work here). A perfect first layer finish is not required for all objects - consider the base of a Yoda or vase - but if you practice getting a great first layer on these non-critical pieces you’ll be prepared when you need a visually perfect first layer on another project.

A number of factors affect adherence of the first printed layer to the bed. These include:

  • surface material
  • surface texture
  • surface treatment/coating
  • bed temperature and uniformity of temperature
  • air temperature
  • chemical bonding or cohesion
  • print speed (see #5)
  • filament temperature (see #9)
  • first layer height (see #4)
  • cleanliness (of bed and filament)

This isn’t an exhaustive list but it does include the big hitters and, as you can see, there are a few of them so it is very important to take a methodical (#2 and #8) and documented (#7) approach when solving bed-related problems. This is also a place where careful observation (#6) can play an important part.

I’m not going to go through all of these in detail now but did want to comment about the last one - cleanliness. Whatever you do, make sure everything near and on your printer is clean and grease free. Silicone greases and lubricants are especially problematic since they are invisible and very difficult to remove. Keep them away from your machine.

Your fingers are a prime source of contaminants. Every time you touch the filament or bed, you risk leaving a greasy print (see my observation in #6) and these can (and will) cause issues. I try not to handle filament with my bare fingers, I use cotton gloves. If you use a plastic or rubber glove, make sure it isn’t coated or powdered - we’re trying to eliminate sources of contamination, not introduce them. On the occasions that I do handle filament with my bare hands I wash and dry them thoroughly first. This is one area that I think affects a lot of user’s and is completely overlooked. How many times have you loaded filament right after eating chips? It introduces a big variable that can be difficult to track down, so develop good habits and eliminate contamination as a variable.

Your fingers can also leave contaminants on the bed when you remove a part or brush off stray filament strands. Don’t touch the bed surface if at all possible. If you do, clean/degrease it with an appropriate cleaner. For uncoated surfaces like borosilicate glass, PEI, the various 3d party surfaces (PrintInZ and BuildTak), and films (window tint, Kapton) you can use isopropyl alcohol. I like to use the little packages of wipes as they are convenient and safe. You can also do a quick wipe of your fingers before tossing it in the trash. It is more difficult to deal with coatings like PVA glue, glue stick, and hairspray since these can’t be cleaned. If you suspect a contaminated coating, your only recourse is to remove and reapply it.

Finally, don’t overlook filament storage, keep it clean too. I store mine in large zip lock bags to keep off dust. You can put packets of desiccant to help remove moisture in the bag too.

#11 Learn to Diagnose.

Patient: “Dr. it hurts when I move my arm like this.”
Doctor: “Then don’t move your arm like that!”

The first point of this joke is, many people do the same thing over and over again without making any changes or stopping to think about what to change (see #8: remember, change one thing at a time) - as if just repeating the same print with the same parameters will magically solve the problem. It won’t (see my footnote below).

The second point of the joke is that the doctor didn’t attempt to actually determine why the patient’s arm hurt, he just had him avoid the problem. I see that a lot too. Usually it takes the form of “I tried printing it with my red PLA and it failed but everything was fine with my blue PLA”. There are many other variations on this (changing slicers for example).

Learn how to diagnose problems. This requires careful observation (#6). Once you’ve identified where the problem occurs (let’s say getting the first layer to stick) then PRACTICE that piece (see #3) until you sort it out. No need to run through the entire process over and over. Isolate the problem, formulate a hypothesis on what you think might be happening and design a test to prove or disprove your hypothesis. If you see a problem and can’t formulate a hypothesis THEN seek help! Or, pre-test your hypothesis here to get some experienced feedback. But, whatever you do, try to work through the diagnostic process yourself first, that’s how you learn.

Footnote: Many years ago (20) my company had an annual laboratory safety week (I worked in a corporate R&D lab with lots of nasty stuff). One of the annual favorites was a gentleman from OSHA who talked about electrical safety. He started his presentation with a black and white video from the 1940s (I think) of a speaker walking up to a microphone on stage. The presentation was being filmed. The speaker reached up and grabbed the mic and was immediately thrown back and fell to the stage unconscious. Members of the audience rushed up to help him. This was all on video. As 4 or 5 people worked to help the victim, you see a gentleman casually walk up to the mic, reach out his hand and touch the mic. He was immediately thrown back and collapsed on the stage next to victim #1. Literally 30 seconds later a THIRD audience member walked up to the mic (now there are 2 victims on the stage and a hoard of people working to revive them) and carefully reached out his finger (looked like the scene from ET) and very, very gently touched the mic with just the tip of his finger. He was immediately thrown to the stage as the third victim. All of this was caught on video. No one died (we were told). Neither of the second two victims stopped to think about the problem, consequences or solutions.

#12 Be a Fanboy. I am probably going to lose some fans for this post about cooling fans!

Don’t think of a part cooling fan as an object, instead, think about “air flow”. If you need cooling on a PLA (or other material) part, then you need to understand air flow. Not all cooling fans are created equally. Consider this, some folks use a 40mm, some a 25mm, some (like me) a 25mm squirrel cage fan. Some are mounted to blow the full fan width stream at the nozzle area, some have a duct or some (like mine) have a very focused soda straw duct). So comments like “run your fan at 1/2 speed” are not specific enough to be useful information. Instead, you need to understand how your particular fan, it’s arrangement, your material, etc, all relate to the air flow.

Using the previous strategies, try to minimize or eliminate the need for any sort of air cooling. Slowing a print down (#5) is one great way to do this. It also gives you a chance to see (#6) where any problem areas on a print might be. You can use this information to focus the right amount of air flow on the problematic areas. The tendency for many is to use as much air as possible. It is much better, more consistent, and more reliable to use as little air flow as necessary. This puts less thermal stress on the printed part.

When you do determine you have a problem that only a fan can solve, start conservatively. I also recommend using a duct of some sort to focus the air flow where you need it. Ideally, the fan would have the ability to follow the print nozzle and direct a small stream of air to the filament right after it is laid down. That is a difficult problem to solve, so most of us direct the air to area around and under the nozzle. But, by directing the air (duct) you can reduce the air flow significantly since it is now focused where you need it.

I suggest doing your own experiments and observations but start conservatively. I don’t use a fan during the entire part. If you find you need to turn the fan on at full blast from no air flow, do it in stages so the hot end can equilibrate properly. You can do this manually, some slicers can support it, or it is easy enough to learn the simple “fan mcodes” to manually insert them where you need them in the gcode file (this is what I do for tricky parts).

M107 is fan off
M106 S50 turns the fan on at 50% - the S parameter is the speed from 0 to 100

Using a focused air flow, lower air flow and the step up technique I just described, you won’t see a significant drop in hot end temperature. PLA has an interesting property that if you change the extrusion temp at the hot end, it has a visible effect on surface sheen of the part from matte to gloss as you raise the temperature. RichRap has written an excellent post about how he uses this phenomenon when printing decorative vases. Although he was varying the hotend temperature, a similar effect can occur with improper air cooling.

I’m also an advocate of using off-platform cooling. By this I mean strategically placed (ducted) fans that direct air to problematic areas of a print. These can be mounted to your vertical columns or simply sat on the bed if it is not too hot. With ducting, you can reduce the air flow considerably and keep the cooling right on a “hot spot”. This technique does require manual adjustment, repositioning, etc. But, it you are trying to print a really tricky part, it might be the only way to do it. Frankly, the part cooling capabilities of desktop 3D printers is extremely primitive at this point. It’s fine for the majority of objects you might print but as we push the envelope on what’s possible, part cooling is one area that needs some more work to automate it.

Consider this, the way I maintain very tight tolerances on the rotating spindle and hub assemblies on my fly fishing reels is to use a low beam of air cooling on the spindle as it’s printed. This “locks” the filament in place in a very predictable way. Once I printed a few parts and measured them to make sure there was little variation, I incorporated that into the design to get exactly the tolerance these parts required.


Calibration objects and other stuff

This first set is a 20mm diameter cylinder .6mm tall. There are 3 variations and the nozzle width is the first part of the STL file name. Start with the pt4mmx20mm-cylinder.stl if you have .4mm nozzle orifice. You can use these to:

  1. get first layer adhesion to the bed
  2. first layer thickness (stop the print after first layer and measure it)
  3. total print height (should be about .6mm)
  4. X-Y calibration (should be 20mm diameter)
  5. eliminate blobbing and other surface artifacts - follow the guide above, print slow, adjust retracts, etc. KEEP NOTES!

pt3mmx20mm-cylinder.stl

pt4mmx20mm-cylinder.stl

pt5mmx20mm-cylinder.stl

pt6mmx20mm-cylinder.stl

Layer Tuning

Here are a few things you can use in a number of ways - everything from testing calibration results to exploring slicer options to breaking in a new filament. These are designed for a .2mm layer height.

The first cylinder (pt2mm tall) I call the Simple Single Layer Test and is my workhorse calibration object for tuning first layer adhesion issues, profiling new filaments and host of other uses. It is one layer high and can be used to test adhesion to the bed and first layer thickness (measure it with a micrometer or calipers and compare to what the first layer height was supposed to be). You can use this to tune your printer and slicing parameters to get perfect infill and explore the effects of speed on infill quality without wasting a lot of time and filament printing larger parts poorly. I also use it when I am testing a new filament to dial it in. It’s a really versatile tool and I use it every day.

75mmDisk-pt2mmtall.stl

This cylinder is .4mm tall, or two layers. It can also be used similar to the first cylinder but the second layer will show issues in orthogonal movements to the first layer. It also provides a little more thickness to measure to verify layer height. It can also help tune the top capping layer.

75mmDisk-pt4mmtall.stl

The last cylinder is .6mm tall, or three layers. Again, it can be used like the first two. I don’t use it as often.

75mmDisk-pt6mmtall.stl

Great Printing!
Michael

note: I originally published a version of this guide on the SeeMeCNC printer forum. Once I have my TAZ and get some experience under my belt, I’ll augment this with more TAZ-specific examples and information.

1 Like

Wow. Nicely done.

great guide! thank you for sharing! :slight_smile:

I am glad you decided to post this onto this forum as well. I just finished ready your version of this here (http://forum.seemecnc.com/viewtopic.php?f=36&t=7361) and I must say it includes some great tips and general knowledge. I recommend everyone to read this, both experienced and beginners.

Thank you for this information!

Great guide! Stickied!

Thanks everyone. I’m working on a more focused “how to” type of guide to accompany this for the delta printers. Once I have my TAZ and get some experience, I’ll be able to do the same for it. I do have Cartesian experience though, having cut my teeth on a Huxley and several SeeMeCNC H1’s. I’m sure it’s like riding a bike…

Cheers,
Michael

Good guide. Good read for people starting out.

Thanks and bump!

Im trying to follow your guide and printing the .2mm disk it is coming out to about .3mm. What would cause that? I am new to this and still have a lot to learn I know so any advice is appreciated. Thank you!

nbart38345 - a .1mm difference could simply be an incorrect Z height setting. Lower your Z height by .1mm and print again.

Printing a single layer (like this object) is not going to help diagnose a Z calibration issue. We’ll assume that your Z calibration is in the ballpark (you don’t mention what printer you are using but if it’s a TAZ 4, 5 or KITTAZ the firmware has good steps/mm values for X, Y and Z. So that tells me you are most likely looking at a simple Z height adjustment.

cheers,
Michael

PS and good for you to start systematically like this! It will pay dividends very shortly!

Ok thank you, and yeah sorry I have a Taz 5.

You touched briefly on filament storage. From what I have learned so far (which pales in comparison to your knowledge), filament storage is fairly important to get right as well. Moisture in filament can and does affect print quality. I did a fair amount of research on this and I think I have hit the best price point and convenience for storage.

Here are some of the containers I worked through:
Open Storage: Bad. Simply leaving it laying about. Collects dust. Collects moisture.
Storage Bins: Fair. Yes, fair! Unless you get reasonably expensive ones they are NOT air tight! If you are buying ones from Walmart for $5, you are wasting money.
Plastic bags: Decent. While they do work, are prone to failure (holes, failed to seal). Ends of filament tend to poke through them (well, obviously not NinjaFlex :slight_smile: ) Their downfall is that each and every bag must be sealed tight and must have a desiccant pack in it. They are the cheapest solution
Plastic Buckets: Excellent. They seal air tight. They are reasonably priced. One desiccant pack per bucket. They are convenient in that they easily stack. Downfall is PITA lids, but thats fixable for a little more money!

My choice…5gal buckets.

Home Depot buckets are $2.50. The expensive part is convenience, the screw lid. You can get black ones for $7.25 at Home Depot too. If black is not your thing…
http://www.ebay.com/itm/GAMMA-SEAL-SCREW-ON-5-GALLON-BUCKET-LIDS-AIR-WATER-TIGHT-FOOD-STORAGE-ETC-/171094497687

So, basic bucket and lid combo is $9.75 plus tax.

Desiccant packs are stupid EXPENSIVE most places. Yes. I said expensive! From Uline, 10g sized bags in a 600 pack container (6000g or roughly 13#) costs $130. That works out to $10 per pound! Off Amazon, 20 1g packages are $5.50 which works out to $124 per pound. Cheapest I could find at Grainger was 1.7# refill bags for $35 ea working out to $20 per pound. In-Freaking-Sane!

How about I let you in on how to score the exact same desiccant material, silica gel, for a mere $1.05 per pound? Here you go: http://www.walmart.com/ip/Mimi-Litter-Cat-Litter-4-lb-Cats/12018928 and if you can’t find that one, then here it is for $1.81 per pound: http://www.walmart.com/ip/Fresh-Step-Crystals-8lb-Cats/10313505 Yep. Cat litter. But don’t go and get just any cat litter, you have to make sure its pure silica gel and contains no clay (clumping).

I learned that secret from a guy at the gun range for use in gun safes a couple years ago. I get the huge coffee filters from a local restaurant supply store and make up 2 cup pouches for the gun safes and I throw in the pouches (instructions below) in individual gun cases.

For our need here, you need this: http://www.walmart.com/ip/FILTER-DRIP-COFFEE-250PK/32559272 or if your work gets a coffee service, yall probably have stacks of them laying around the break room. See if you can score a few for free. I did. Our boxes of coffee come in 100 coffee packs. Yet there are 250 coffee filters in each box. Hot dogs and buns take two.

And you will need a stapler or hot glue gun. I use the stapler as its less mess and cheaper. And I don’t have to worry about the staples in the oven when I recharge them. Brain says the hot glue is ok at the 180f recharge temp but I don’t want it opening up in the oven. Gut says go with staples.

So for a 5gal bucket (1155in3), I go with 1/2 cup. I am ok with putting 2x what I need in a 5 gallon bucket since 8 pounds of it only ran me $15. You are going to make a pita bread type pouch. Take two coffee filters, lay one on top of the other flat on the counter/table. Fold a little of an edge over and staple, only need 1/8" fold. Rotate, fold, staple. Keep doing that until you only got a couple inches left. Measure out 1/4c of cat litter and pour in your coffee filter pouch. Measure and add another 1/4c and add it. Doing 1/2c at once, I can’t manage without spilling it. YMMV. Finish stapling it closed. You will probably use about a dozen staples on the large 12c coffee filters.

Repeat about 100 times until you have used up the cat litter :slight_smile: No, really. Go ahead and make up a bunch of pouches while you got your stuff out. Also, make up some pirogi pouches too (single filter folded in half with just 1/4c). And make up a few 1/8c. And make up some smaller ones by cutting the filters up into rectangles and putting a tablespoon in each.

Once you got them all made up, heat your oven up to 150-180F. Spread the packs out on cookie sheets or aluminum foil. Bake overnight with the door cracked open slightly to let moisture out. Next morning shut the oven off and allow to cool to the point you can handle them. You can also use a dehydrator if you have one and the packs fit in it.

Grab your cooking scale and weigh each packet in grams. Take that figure and multiply it by 1.3. Using a sharpie, write that figure on the packet somewhere. Each will weigh slightly different unless you were extremely fastidious as to measuring the cat litter and counting staples. I was not.

Why? Knowing when to recharge it! Silica gel can absorb up to 40% its weight in water. So I cut it off at 30% as its effectiveness declines after that. So multiplying the weight times 1.3 (or 130%) gives you a target weight to recharge at. That way you don’t have to do the math later, you did it now :slight_smile: Simply check them once a month or so and if they weigh more than their target weight, time to recharge.

Remember all those extras? Seal them up in ziplock bags or if you have a foodsaver, vacuum pack em. When you need them they will be made and ready. Those half sized ones are good for boxes and pistol cases. The tiny ones I had you make with a tablespoon, those are perfect for spools in ziplock bags. Or if you got a filament spool thats not very happy with its moisture content and you are not in a hurry for it, you can throw one of the 1/4c bags and the spool in a ziplock bag for a week.

Any leftover cat litter, yea, I know you didn’t process all 8# did you? Load gallon ziplock bags to about 75% full, seal. Drop that into another gallon bag and seal. Throw all those (mine equated to about 3 leftovers) back in the resealable cat litter bag (Fresh Step bag) and seal it back up. Leave a cup or so scraps in the bottom of the cat litter bag to clean up moisture in the bag before it gets to the ziplock bags.

The 8# bag will be enough for about 36 of the larger packets. Give or take. Just about $0.40 per packet. Even if you go overboard and put 2 in a bucket, you are still under a buck per bucket!

Want to monitor your buckets?
http://www.ebay.com/itm/231416652242?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

There is a recess in the center of the Gamma lid that these will fit perfectly in. I used my laser cutter to whip out 2.24" holes in the center of all the lids in just a couple minutes. Then put a bead of hot glue on the back of the hygrometer and drop it in the hole. Now you got a bucket with built in meter :slight_smile:

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Thanks Wolfie, I am about to finally have the problem of too many started filament spools. Sounds like I will be packing and drying cat litter this weekend. Good Stuff.


Questions:

  1. Do the Lulzbot 1 kg spools fit in the 5 lb buckets? I use PLA if that matters.
  2. If the Lulzbot spools fit, can you store multiple spools in a bucket? (seems like you could stack 2-3 in one? If so would I add a dessicant packet per spool?


    Thanks again.

To answer my own questions:
Lulzbot spools fit great, and you can fit up to 5 in one 5 gal bucket!

Thanks Wolfie for a great idea on filament storage. I hadn’t thought about the 5gal buckets but they are ideal. Too bad they don’t come in clear! But a tip: snip off 3" of each filament you put in the bucket and tape that to a card on the top with the filament brand/type. That way you know the color and contents of the bucket without opening.

cheers,
Michael

Wow, great info about storing filament, thanks! :slight_smile:

If you have a laser cutter…may I direct your attention to my first “thing”.
http://www.thingiverse.com/thing:693093
I bent a piece of coat hangar wire and wrapped it around the bucket handle near where it attaches to the bucket. I hang these on that improv hook.

Then when I pull a spool, I take it to the printer with me as it has the temps and extruder calibration numbers written on it.

Great instructions on the cat litter… and nice find on the screw on lids.

I’ve been meaning to convert to cat litter from for my stash of filament which is already in the paint buckets. But I’m using the cheap press on lids… might need to look for the screw on type.

Found this from Taulman’s site a few months ago… but haven’t been able to find the source again:

You’ve been active on thingiverse too… need to post some of your great projects here. :slight_smile:

The screw on type are available in the paint dept at Home Depot. SOOO worth the money over the PITA standard lids.

Keep in mind, all the spools I have seen from Taulman are not 1kg. They are about half the diameter and a bit thinner width wise than the mostly standard 1kg spools. You might get 3 taulman spools across in the bucket but I doubt you will get any more than two across of the standard 1kg. Also, you will have to move the shaft down away from the lid to account for the larger diameter 1kg spools.

Yeah… The screw in lids have got to be so much easier than the snap on lids. :slight_smile:

And you’re right the taulman spools are smaller than normal spools. Multiple dowel rods in that taulman desin, might get a few more normal spools in a bucket.

Hefty’s 18qt container fits 4 or 5 eSUN ABS spools (200mmx70mm) side by side nicely. Need some weather seal to make it airtight, though.