File:Nice Fuckin Model.webp

2026-01-10T17:30:16Z

Theshittinator:

An infographic that shows people how to get added to the GunCAD Index

Choosing the Right Plastic

2026-01-04T02:09:58Z

Theshittinator:

When [[3D Printing|3D-printing]] a firearm, picking out the right plastic is important. Not all plastics are created equal, and some may fail in a way that could harm the user if used in the wrong application.

This guide will go over some considerations and commonly-used types of plastics that tend to meet the needs of firearm design.<blockquote>'''Note''': Be aware that '''this guide does not trump designer recommendations''', especially for tested designs. If the specification for a design dictates the use of a particular plastic, one should not deviate from that instruction without good reason.</blockquote>

== Common Plastics ==
Below are some tables of often-used plastics, categorized based on suitability for DIY firearms:
{| class="wikitable sortable"
|+Good Plastics
!Plastic
!Pros
!Cons
!Notes
|-
|PLA+
|
* Does not warp very often
* Cheap and accessible
* Does not emit noxious fumes
* Does not require CF/GF infill
* Yields instead of breaking
|
* Extremely low temperature resistance
* Can sometimes be confused with PLA-CF and Silks, which are not suitable
|The go-to basic plastic and what most DIY firearm novices cut their teeth on.
|-
|PA-6
|
* Very high temperature resistance
* Pleasing surface texture that hides layer artifacts
* High durability
|
* Expensive
* High print temperature required
* Most blends use CF/GF infill, which requires hardened steel nozzles
* Must be dried before and during printing
* Creeps if not [[Annealing Plastics|annealed]]
|A tried-and-true durable filament and oftentimes the plastic of choice for experts. Variants of PA-6 are often used in commercial plastic firearm parts
|-
|PA-12
|
* High temperature resistance
* Pleasing surface texture
* Cheaper than PA-6 with most of the same benefits
* Less hygroscopic than PA-6
|
* Lower temperature resistance than most other Nylons
* Must be dried before and during printing
* Creeps, albeit not as badly as PA-6, if not annealed
|PA-6's little brother shares a lot of its benefits with less headache
|-
|ASA
|
* Cheap and accessible
* Incredibly high bed adhesion
|
* Off-gasses styrene while printing and must be printed in a filtered enclosure
* Not very abrasion-resistant
* Mid layer adhesion
* Incredibly high bed adhesion -- use a release agent like gluestick
|Similar to ABS, ASA takes almost all of its benefits with fewer downsides, though it still doesn't make it suitable for all DIY firearm use cases.
|}
These plastics should be avoided. They've been tested and tend to produce undesirable results when used to produce high-stress parts:
{| class="wikitable sortable"
|+Bad Plastics
!Plastic
!Reasons to Avoid
!Notes and Exceptions
|-
|PETG
|
* Failure mode is breakage
* Low impact resistance
| rowspan="4" |In cases where risk is low, such as on furniture, weaker plastics may be acceptable for their UV resistance, heat resistance, or price point.
|-
|PLA
|
* Failure mode is breakage
* Low impact resistance
* Low temperature resistance
|-
|PLA-CF
|
* Typically does not contain PLA+ additives and is thus a weaker PLA
|-
|Any recycled filament
|
* Recycled filaments are never as good as a virgin plastic
|}
== Considerations ==
The following are key reasons one may choose any given plastic over another:

=== Impact Resistance ===
The ability for a plastic to withstand an impact without breaking or yielding is called its '''impact resistance''', and it's one of the most important characteristics for most parts of a firearm. Several functions rely on high impact resistance, most of them things that happen while the firearm cycles.

=== Heat Resistance ===
Each plastic has what's called a "glass transition temperature" (Tg) which is the temperature at which it starts to lose its crystalline structure and begins to flow and warp. If, say, your receiver hits Tg while firing, your gun may start to meltdown and malfunction. Some plastics have glass transition temperatures low enough that they cannot withstand the open sun in certain regions' summers.

In general: the higher the printing temperature, the higher the continuous round count.

=== Rigidity ===
Plastics are floppy, generally. The more plastic in one place, the more it can support itself, but some plastics are less floppy than others.

If a plastic is particularly flexible but has enough desirable qualities in other areas -- as is the case in most Nylons -- then carbon fiber/glass fiber infill may be added. This increases rigidity and oftentimes crystallinity, but at the cost of layer adhesion. How exactly these infills behave is dependent on the plastic at hand.

=== Hygroscopy ===
The tendency for a plastic to absorb water from its environment is referred to as its hygroscopy. It is a slow, gradual process that is never driven to completion but instead hits an equilibrium with the ambient humidity in the environment. Plastics that have absorbed water often exhibit lower rigidity and higher impact resistance.

Filaments that are particularly hygroscopic should be dried before printing and may even need to be printed from a specialized dry box so as to not reabsorb moisture over the duration of a print. When melting a plastic that has absorbed water, the water will boil to steam at the hotend and introduce voids in the print, ruining it.

=== Creep ===
Given constant pressure (such as that imposed by a spring), some plastics will permanently warp out of place over long periods of time. This phenomenon is known as creep. Creep can be mitigated for via fillings and through the use of clever part design, such as the use of reinforcement plates on an AR-15-compatible fire control group.

=== Failure Mode ===
The way in which a plastic fails is an important consideration when risk is high, such as in the case of a printed upper-receiver. Plastics tend to fail in two ways:

* Breaking, in which the plastic shatters violently; or
* Yielding, in which the plastic stretches and taffies out

Yielding is often more desirable as it tends to constitute less of an operational risk to the wielder.
[[Category:Guides]]
[[Category:3D Printing]]

MediaWiki:Sidebar

2026-01-04T02:09:17Z

Theshittinator: Casing consistency

GunCAD Wiki:Style Guide

2026-01-04T02:09:05Z

2025-12-23T20:17:18Z

Theshittinator:

A card for the FGC-9 MkII on GunCAD Index. It shows off all metadata and the verification indicator.

Joining the Community

2025-12-23T20:03:19Z

Theshittinator:

'''{{Glossary|GunCAD}}''' (also '''3D2A''' or '''FOSSCAD''') is a broad, decentralized community of hobbyists who create and share designs for DIY firearms and related material. It moves rapidly and has been subject to frequent deplatformings over the years. This can make it difficult for a new community member to keep up with developments.

This guide will list useful resources for participating in 3D2A discussions and keeping up with development. Note that these places are for discussion; to find files, see [[Finding Tested Gun Designs]].
== Newsletters ==

=== Guncad Digest ===
The [[Guncad Digest]] (https://guncad.substack.com) is a well-curated biweekly Substack newsletter that gathers information on new releases, betas, and developments. It also keeps track of the larger landscape, where 2A or printing-specific developments may be relevant.

You can [https://guncad.substack.com/about subscribe to the Guncad Digest] to ensure new issues are delivered to a Substack or email inbox.
== Dedicated Discussion Forums ==

=== GunCAD Forums ===
The [[GunCAD Forums]] (https://forum.guncadindex.com) is a federated forum for discussing all subjects related to DIY firearms. Leveraging the Lemmy software, its federated nature make it highly resistant to censorship and deplatforming, making it a stable location for discussing and asking questions related to DIY firearms.

=== FOSSCAD.io ===
[[FOSSCAD.io]] (https://fosscad.io) is another federated Lemmy instance. Due to their federated nature, all Lemmy instances can discuss the same posts as though they were all the same website. It is also a stable location for discussing DIY firearms.

== Social Media Groups ==

=== /r/3D2A ===
One of the few subreddits for DIY firearms still standing, [https://reddit.com/r/3D2A /r/3D2A] allows users to discuss and show off builds and new releases with some restrictions. <blockquote>'''Note''': Reddit has very strict rules about what can and cannot be discussed, especially regarding DIY firearms. These rules are consistently enforced on /r/3d2a -- users are encouraged to read and follow them. Limitations include:

* Users cannot discuss, link to, or vaguely allude to file-hosting websites
* Users cannot solicit sales of any sort, including parts kit vendors

Rule breakage is swiftly punished. Users are encouraged to discuss those topics on a dedicated forum.</blockquote>

=== The Real 2A Printers! Facebook Group ===
"The Real 2A Printers!" (https://www.facebook.com/groups/1368258840310204/) is the largest Facebook community dedicated to 3D2A. It's a good place to view updates and ask questions related to 3D2A.<blockquote>'''Note''': Just like Reddit, there are very strict rules on Facebook related to discussing 3D2A. Rule breakage is swiftly punished.</blockquote>

=== 3D2A Facebook Group ===
"3D2A" (https://www.facebook.com/groups/344556773663993/) is the second largest 3D2A-related Facebook community.<blockquote>'''Note''': Just like Reddit, there are very strict rules on Facebook related to discussing 3D2A. Rule breakage is swiftly punished.</blockquote>
[[Category:Guides]]