Embedded Files
FDM uses rolls of filament in different kinds of plastics. The different material properties will affect the outcome of your printed piece. Knowing the difference is crucial, whether you are commissioning a piece or making it at home. FDM printing has the widest range of usefulness to Cosplay compared to Resin Printing.
The most common kinds of filament available commercially are ABS, PLA, PETG, and TPU. There are, of course, tons more, but these will be the most commonly used for Cosplay by beginner to intermediate printers.
What Material to Use
What Material to Use
Depending on what you are creating, different materials will have different benefits and drawbacks. Choosing the right base material will be the make-or-break between a finished piece that looks amazing, or a sad, broken hunk of plastic.
Extremely high quality final product options available at cost of using somewhat caustic and stinky materials. Use of PPE and ample ventilation makes it only a moderate challenge under appropriate conditions.
Pros:
Pros:
Strong and Durable
Impact Resistant
Temperature Resistant
Acetone-smoothing and welding
Can be sanded glassy smooth
Lightweight compared to other similar thermal-plastics
Cons:
Cons:
Releases toxic and stinky off-gas.
Only print in well ventilated areas or with appropriate filtered enclosure.
Prone to warping during printing without enclosed, heated chamber
Distorts / Brittle when exposed to UV light.
Not recommended for extended outdoor use without UV resistant coating.
PLA
Absolute best for beginners for 3D printing and prop-work. Lowest challenge for printing, but least structurally sound final products. Excellent for testing and prototyping self-drafted designs before committing to ABS for final product.PLA
Pros:
Pros:
Available in HUGE variety of colors and styles.
Different inclusions available for translucent, sparkle, glow in the dark, and other special effects.
Easy to print with
Extremely beginner friendly
No stinky / toxic off-gas
Cons:
Cons:
Not temperature resistant
Absolutely WILL deform if left in a car or even in direct sunlight too long.
Somewhat brittle.
Very UV sensitive, will warp or become brittle after prolonged UV exposure.
No chemical smoothing
Does not sand well
Pros:
Pros:
Strong and Durable
Chemically Resistant
High Impact Resistant
Temperature Resistant
Somewhat easy to print with.
Prone to warping if temperature in area is inconsistent.
High quality finish
With the right settings, you can use PETG to replicate glass or gemstones.
UV resistant
Good for prolonged outdoor use in moderate temperatures.
Cons:
Cons:
No chemical smoothing
Difficult to store
Hygroscopic - absorbs ambient moisture before printing which can ruin a print if not kept dehydrated prior to printing.
Sticks too well to print bed, can cause damage to bed if not prepared correctly ahead of printing.
Hard to paint and post-process
Caution: High challenge level, requires specific print configuration and A LOT of attention to settings and material quality when setting up the print.
Pros:
Pros:
Flexible
Soft and elastic, perfect for joints, compression, or flexible parts.
Different "stiffness" qualities available.
"Harder" TPU prints easier than "soft" TPU
Chemically resistant
Temperature resistant
Impact resistant
High Friction - great for grip or purposeful impact protection.
Cons:
Cons:
Prone to failure and clogging due to flexibility in filament.
Softer filament can stretch or compress in drive motor or hot-end and clog.
Much more likely to succeed with a Direct Drive printer.
Hygroscopic
Requires airtight storage or frequent dehydration before printing.
Requires very specific print settings to ensure success.
Tips for Printing Props and Armor
Tips for Printing Props and Armor
FDM Prints benefit from the right settings applied. Here are some general tips for setting up a functional print for most props and armor.
If commissioning a piece, you should be able to request specification on settings being used and compare the information given against the guides here to judge if the commission will suit your needs, and help guide you to the right solutions for the next stage of your project.
- More Walls, Less Infill
Infill is the mesh-shapes that fill the "solid space" inside a print. It's purpose is to protect against crushing, and support the top-most layers.
The default setting on most slicers is between 10% - 15%. This means that 85% - 90% of the interior of a print is air. This creates flexible, light-weight prints and reduces the amount of filament necessary for a functional piece.
Increasing or reducing this quantity can affect the strength and weight of a piece. For most props, unless they are under tensile stress, you can get away with 5% - 10% infill.
10% infill and 1mm walls can handle around 50lbs (22kg) of force before failing. 20% can handle over 100lbs (46kg). A good estimate is that each 10% increase will double the previous weight ability, so unless you expect to need to support nearly 400lbs (181kg) of sustained crushing pressure, you don't need to ever go higher than 40%.
DO NOT PRINT AT 100% Infill unless you are CERTAIN you need the tensile strength. (Spoiler: You don't unless you are creating something intended to support torque AND pulling on an industrial scale.) You will create a more brittle part because any kind of stress will cause the layers to separate across the entire piece instead of flexing slightly into the air layers.
The infill pattern you pick DOES affect the strength of a print and the amount of time and filament spent on the interior. Cytron Technologies has a comprehensive breakdown of which infill patterns work best for which print needs.
Walls (or Shells) are the solid outer rings of a print.
Most slicers default to 1mm thick for most print profiles.
Bumping that number to between 2mm and 5mm or more will make stronger props without using too much more filament. This still allows the print to flex slightly to protect it from impacts or shattering along the layer lines.
This also helps with hiding infill shapes from showing through translucent filaments, improving LED diffusion or prevent light escaping through the body entirely, and creating depth to sand a part without breaking through to the infill by accident.
Infill Percentage Examples - Cytron Technologies
2.
2.
Use the right material for the job
Use the right material for the job
Use the guide above to choose which material will suit your project better.
Make sure you are using the right GLUE and PAINT for the kind of materials you're using. Some plastics are chemically resistant or reactive and the wrong paint or adhesive will either not work at all, or cause the part to melt or deform.
Assembly
Assembly
Some prints are only possible to make in several parts, whether it's due to size, or because of print orientation needs to achieve best results. Depending on the design of the print, there are multiple ways to assemble and secure a print.
Some designers create large scale props with twist-locks for things like long staffs, but don't count on it.
Depending on the material used, you will need specific types of assembly techniques to keep the parts together.
Glue
Glue
Glue depends on the chemical bonds between the adhesive and the plastic surface. Plastic is difficult to glue in general due to smooth surfaces giving very little for the adhesives to bond to, so things like using rough-grit sandpaper to score the joining surfaces to create more grip surface may improve your joins when using the proper material.
Always glue BEFORE painting, including primer and spot-fill. These layers can tear free and cause prints to fall apart. Plastic-to-plastic will always be the strongest bond. Consider setting down painters tape before finishing to reserve a glue surface if finishing parts separately.
ABS:
ABS:
Acetone Joining - "Solvent Welding"
Melts the ABS together for a chemical fusion rather than adhesion
Uses acetone (nail polish remover) so use in well ventilated area and put a protective layer on your work surface.
Plastic Weld
Contact Cement
PLA:
PLA:
Super Glue - "cyanoacrylate"
works for small parts that are not structural or under tension.
Best for peg-and-hole joins and small surfaces.
Not great for large surfaces or face-to face bonds.
Designed for PLA, chemically welds the plastic together.
PETG:
PETG:
J-B Weld Epoxy / Plastic Weld
E6000
Super Glue
TPU:
TPU:
Polyurethane Glue
Gorilla Glue or Loctite PL
PVC Cement
ShoeGlue
Mechanical Bonding
Mechanical Bonding
Mechanical bonds refer to things like twist locks, welding, screws, nails, and other more traditional joining techniques like you would see in other manufacturing settings. Depending on the finish you are trying to achieve, your joins may need additional post-processing to hide, disguise, or repair the appearance of the join.
Plastic Welding
Plastic Welding
Using additional filament as the "solder" and either a rotary tool or soldering iron to melt the plastic into the print.
Good for filling cracks, join-seams, or missing material.
Can press jewelry wire into seam to "staple" segments together and cover over with plastic.
Good for creating organic burn or pocked surface textures.
Creates a very rough and raw area that would require more post-processing to smooth out or disguise.
Press Threads
Press Threads
Uses a soldering iron to press brass tubes with screw-threads into pre-modeled holes in the print to grip small screws.
Good for assembling pieces that need to separate for storage or travel, or to access internal structures such as battery compartments
Does not support a lot of torsion and can tear loose if under tension.
Pre-modeled holes may not be included in original print and needs to be added after the fact with a drill or as modification to the print profile in the slicer program.
Some prints can use the friction hold of the plastic with things like wood screws instead but these are less structurally sound and can destroy a print if dropped or weighted incorrectly.
"Spackle"
"Spackle"
Uses mesh or fabric and glue or bond putty to create a grip surface and build up material around the join area.
Good for repairing holes, reinforcing joins that must not flex, and preventing separating and cracking.
Creates large layers of materials and requires a lot of post processing to disguise or smooth.
Post-Processing and Finishing
Post-Processing and Finishing
Taking your prints from looking like cheap plastic (which, to be fair, it technically is) to something high quality takes a decent amount of post-processing and finishing techniques. You can use any quantity and combination of the following techniques and tools to achieve the end result you are looking for with the tools and skills available to you.
Remember, pay attention to your PPE and follow all safety advice when using any finishing techniques.
Depending on the material you printed with, there are a few different ways to smooth the print and remove visible layer lines.
If you are the one printing, you can start by setting up your print profile to reduce the visibility of the layer lines. Using techniques and settings in the print profile can create a foundation that requires much less post processing to achieve a quality result. You can also choose to print in Resin over FDM to create very finely detailed prints with nearly invisible layer lines.
Depending on the material you're using, you have many different options to use in different combinations.
Sand
Melt - Chemical Smoothing or Heat
Use caution. Chemical smoothing uses caustic solvents to chemically melt the outermost layer of a print into a semi-liquid state. Improper use can be dangerous and carries a risk of melting your print into a blob. This method removes and obscures sharp details into more soft, organic shapes.
Heat treating uses a heat gun on the lowest setting and slowly heating the surface of the print evenly to soften the layer lines.
Low infill or thin walls have a serious risk of buckling, and fine details may droop or warp.
Cover - Spot-fill putty, primer, resin, or glue.
For solid, opaque parts, the best method by far is a combination of Cover and Sand repeated until you achieve the desired result.
Start by sanding off extra edges with a medium grit sand paper.
Hand sand low-temperature plastics to avoid melting them. PLA should not be sanded using a mouse sander or pen sander without careful attention as the friction heat can melt the part into a sad blob.
Spray over with a Sand and Fill primer.
This is like a thick spray paint that will settle into the cracks and grooves of a print.
Be careful not to over-spray. Deep primer puddles will crack as they dry and undo the whole point of it.
Alternatively, you can paint over with a mixture of wood-glue or fill putty and acetone (use caution).
Sand again with a finer grit sand paper. - WEAR YOUR PPE; you don't want that in your eyes or lungs
Look for high-spots where the plastic shows through to make sure the print is still smooth
Spray or paint fill putty over the piece again if necessary to fill in any deep cracks or exposed spots.
Repeat sand with finer and finer grits until you get the smoothness you want.
Spray paint or lacquers can achieve the last level of smoothness instead of sanding more.
DO NOT SAND AFTER PAINTING - many paints contain lead and other harmful chemicals that should not be breathed in.
See our PAINTING TIPS for more information on painting props.
For translucent or transparent parts that need to remain so, use your print settings to your advantage to reduce the need as much as possible. Print orientation, smaller layer lines, and tweaks to other print settings can get very close to glassy, but not perfect unless you are using a resin printer.
If the FDM print can be milky or smoky, lightly sanding the surface with progressively finer grit sand paper can allow light to pass through while creating a soft, smooth surface, though it will not be glossy unless you spray over it with a glossy lacquer.
If the print must be glassy, you can coat over it with a clear UV resin and cure it or a clear spray fill.
be aware, close inspection may still show layer lines.
Ideally, you would print using a "Glass" ABS which can be smoothed with Acetone to melt the filament lines together to appear more glassy.
Ultimately, you should be prepared that all smoothing processes will be time consuming and require more than a little effort for highest quality results.
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