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  1. #1

    Another "Which Filament" thread.

    I did read through many filament posts, here and elsewhere, but im still not exactly sure which to use for my purposes. I have spent days studying properties of filaments and have read about or watched different reviews and such. So my new CR-10 S5 arrives today and im ready to purchase some filament. I have designed several parts for my hobby which is RC Sailboats (racers). Not much interested in printing Vases, Action Figures, or some artistic accomplishment. Dont need too much advice on how to set-up or improve my printer quality with engineered addons. I pretty much have those bases covered.My parts have several requirements, which leads me to questions.
    Requirements: 1. Parts will be subject to water imersion and salt water from time to time as well. 2. Parts will be subject to heat/sunlight while the boat is sitting, waiting to be used. We do try to use shade or a towel to cover. Many of our boat hulls and appendages are Carbon Fiber laminates. 3. Parts need to be light, stiff and strong, 4. For some parts I will need to do a split on the slicer and then bond. Most all parts used will have a purpose involving stress.I can engineer the right balance of lightness, strength, and to a degree, stiffness into the parts, but with the choice of materials available, it becomes a jungle as to choice, not so much brand, but type. It would be nice to use just one material for everything and I think I can, depending on the input I receive. I understand that my abilities and accomplishments will be limited by my printer type (FDM) and my printer quality. Its not a 5K or a 65K printer. So just to open up on filament, my sailing buddies are saying to use ABS and of course it seems a good base material to start with. I would definitely want to take advantage of using the Carbon mix on any material I use, so lets just say CARBON (insert filament type here). I am in the process of shopping the high performance heated bed option, so that should be considered. I will also add one of the all metal hot ends so i can use something close to 300c if necessary. And an enclosure for quality of print. My main concern is trying to print a "keel fin" It would either have to be a vertical print which would place the layering of the filament in the wrong direction for strength, and present a tenuous build for the printers abilities, or do a vertical split and lay the piece down on the bed. This would give me both the best filament alignment and provide a huge flat base to work from. Since the keel is dimensionally thin on the chord of the profile, this wold result in a rather flat finished piece. Yes, it is designed with a NACA profile, hence the split, and a good advantage for a very good print. The problem now becomes one of bonding. The keel would be approx 18 inches vertical height with the top 4 inches inserted into a Trunk inside the boat. The other 14 inches will extend down into the water with a maximum weight, torpedo shaped, lead ballast bulb, of 4 pounds on the bottom end. That keel has to be "STIFF". The less deflection the better. Now, there isnt any real point in placing the keel at a 90 degree angle with the weight hanging off the end to see how much deflection is involved. If the boat is sailing in the water and the healing angle goes more than something around 60 to 65 degrees it doesnt matter anyway as the boats performance is already degraded by the inefficiencies of the rest of the dynamics involved. Now, I need advice on what filament(s). Please.
    Last edited by Just Harry; 08-15-2018 at 01:30 PM.

  2. #2
    eSun PETG will give you better than ABS Strength with more flexibility and no need for an enclosure to print it. MakerGeek PETG is more rigid than eSUN and FDA approved for food contact.. Just started using it and seems less sticky that esun. Also prints ate 255 rather than the 245 of Esun.
    Sounds like you are about 6 months ahead of yourself.. Unless I read this wrong you don't have a printer or the slicing software? There is a bit of learning to do and probably should do that with PLA, you can develop your parts in PLA then print them in the more expensive more difficult material after you are on your feet.

  3. #3
    @Airscapes,, Thank you for your input. Yeah, well, printer arrives today. I dont need/want flexibility in any way shape or form. PETG would be a good choice I understand, but I also understand that is has poor bonding characteristics. Dont need/want FDA approval for anything. I can read thru software at an amazing rate. If it takes me six months, I will kill myself. I will use either freeware or $150 dollar version for Slicer. Im retired. I have hours and hours of time to slam thru this. I have a new boat mold arriving in a few weeks and I want to make the hardware and appendages I 3D designed for the boat, get it in the water for testing and sail off to a national championship. This 3D printing arena of life is not my main focus, merely a tool amongst other tools for my real Hobby and passion. Thanks for your suggestions. I will reconsider them deeper.

  4. #4
    Ok man you enjoy.. you know more than we do!

  5. #5
    Did you really have to say that? Im not enjoying anything. You gave your opinion. I am considering PETG. Your comments about my level of aptitude are instigating. Just leave it. By the way the WE do at the end should be singular. You have no right to include the people who frequent this forum other than yourself. Really, Just get lost.

  6. #6
    Super Moderator curious aardvark's Avatar
    Join Date
    Jul 2014
    pet-g has fabulous layer bonding.
    It can be tricky to get the settings right - but once you do layers are not a problem.

    The LAST material you want to use is 3d printed abs.
    It's sucks in outdoor applications is broken down readily by sunlight and fdm abs is one of the weakest materails you can use.
    I have no idea why abnyone still uses it. bog standard pla - fdm printed - is superior in every way.

    Pla would actually suit your purposes quite well. Certainly for prototyping purposes
    Carbon fibre infused filaments are weaker than those without, slightly stiffer - but the stiffness is offset by increased brittleness.
    They eat nozzles and aren't even conductive enough to be of any real use.
    It's a gimmick that doesn't deliver on any aspect.

    But spend some money and you can start using serious filaments.

    ninjatek's Armadillo is probably exactly what you want. It's a rigid polyurethane. Tough as nylon, stiff as pla with more strength than pet-g and excellent layer bonding. Also as easy as pla to print as well as light.

    And children - play nice :-)
    Last edited by curious aardvark; 08-16-2018 at 09:43 AM.

  7. #7
    @Aardvark,,, Thanks for the input. I am not adverse to any material if it can provide what I need. This rigid polyurethane sounds like a winner, but I have a question. The Data Sheet at Ninja doesnt give any flexural test data, but Im thinking that it would work and certainly worth a try. If you will look at the attachment you will see a long, thin, piece. 18 " long, 3.25" at its widest point below the trunk, and just under 2" at the bottom. Those are profile dimensions. The thickness profile starts at approximately .215" at the top and tappers down to .180" at the bottom. It has a NACA chord profile. For all FDM printers can do, this would be a tough assignment. It would need a split on the vertical, with a resulting left and right side profile. That is now highly doable and would be aligning the print grain in the best way to resist deflection. The problem then becomes how to bond the two pieces together. Is this product even friendly to bonding to itself? Let me give you an idea of the stress involved. The top portion of this keel, 4", will fit inside a trunk in the boat. The remaining 14 inches will extend down into the water. On the bottom end of this piece, will a keel bulb in the general shape of a torpedo. It will weigh approx. 4 pounds or a bit less. IT has to be resistant to deflection when the boat heals over. These are sailboat racers, not motorized. Its not necessary to bench this piece and clamp at a 90 degree angle to perpendicular and put 4 pounds on the end to test deflection. The most angle that efficiency will be needed to around 65 degrees from perp. After that, all the sailing dynamics are seriously degraded and a flexing keel wont make much difference. I can buy a laminated carbon fiber/epoxy keel fin that is actually overbuilt for the job but its cost is around $200 and its not a commercial purchase. You may or may not get one in a decent amount of time. Its for a different boat and is definitely not optimal for the development boat class I am building for and competing in. If I can find the right build for this piece with material, design, and 3D printing,, I will sell dozens of them. This one piece is just part of a collection of Hardware I have designed in 3D (for 3D printing) for the boats, but it is the most important piece to succeed with. The rest are a piece of cake. Any further assist will be greatly appreciated. Thanks Again.
    Attached Files Attached Files

  8. #8
    Super Moderator curious aardvark's Avatar
    Join Date
    Jul 2014
    first off a couple of things. Can you try and do paragraphs, just makes it a LOT easier to read :-)
    And you'll find that you need to be using millimetres for all measurements. Inches just confuse matters and most slicers just look at them go: burble burble burble :-)

    that file would print as it is - don't see any issues.
    You'd need a fairly high resolution, but you've got a nice flat base to start with.
    Hell you could always use supports - I pretty much always design a print so that I never use supports, but that takes practice and without a printer. Any designs you make will NOT be optimised for supportless 3d printing.

    But as long as you expect to do some post print filing and sanding, it shouldn't be an issue.
    Only real issue is length.
    If you split it in half lengthwise you'd need to dogleg the cut so you have overlapping section to glue.

    Strength on fdm prints is largely dependant on print orientation.

    Print that peice flat and pla would be absolutely fine.
    But the armadillo would be almost as strong as the carbon fibre one.

    Bound to be pu glue/solvent around.
    For pla i use uhu all purpose. I get a partial dissolve so very strong bond.

  9. #9
    . Hello Aardvark,Ok I will run millimeters as its not really important to get it perfect in the discussion anyway. I thought I might have not explained myself completely thoroughly, and I was right. The split will be lengthwise, but not on the surface you are thinking of. I am talking about splitting from the front to make two flat halves and an easy build for the printer. Since the last post I did some research on the Armadillo filament Thermoplastic Polyurethane. Its very easy to chemically bond(glue) this product. No problems at all. Its looking like I will definately buy a pound and test it out. I appreciate your contribution, thanks man.

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