Approved Filaments
The most important technical requirement in the program. Get this wrong and you can damage your customer’s silver.
The Rule
PETG body required for all Coinfinity products. No PLA on contact surfaces, ever.
This applies to both Model A and Model B — any product carrying Coinfinity branding or attribution must follow this rule. There are no exceptions.
Why PETG, Not PLA
PLA is hygroscopic (absorbs moisture from the air) and degrades via hydrolysis, releasing acidic residues over time. These outgassing byproducts can accelerate silver tarnish, especially in enclosed storage where airflow is limited.
PETG, by contrast, is:
- Chemically stable (minimal off-gassing, low VOCs)
- Lower moisture absorption (0.1–0.5% vs PLA’s 1–2%)
- More durable over decades (10–50+ years in controlled storage)
- Heat-resistant (70–80°C vs PLA’s 50–60°C)
- UV-stable and impact-tough
This is also a selling point. When listing Coinfinity products, emphasize PETG construction — many customers don’t know the difference, and explaining it builds trust:
“Made from PETG — the only safe material for long-term precious metal storage. PLA-free.”
Approved Filaments (Model A)
If you’re an Authorized Coinfinity Reseller (Model A), you must use one of the following specific products for the matching color:
Black
- Creality CR-PETG, 1.75mm
- Used for: black bins, stacker bodies, lids
- Available on Amazon
White
- Bambu Lab PETG Basic, 1.75mm — White
- Available at Bambu Lab store
Blue
Two approved blue variants — either is acceptable:
- Bambu Lab PETG Basic, 1.75mm — Navy Blue
- Bambu Lab PETG Basic, 1.75mm — Reflex Blue
Available at Bambu Lab store
Other colors
Other colors require Coinfinity approval before use. Limited-edition or seasonal colorways may be released and shared with the reseller network. Contact info@coinfinity.us before deviating from the approved list.
Filament Choice (Model B)
If you’re a Licensed Maker (Model B), color is your choice. PETG is still required, but any color and any reputable brand works for your own brand.
We still recommend the approved list above for quality consistency, but it’s not required for Model B.
Support Interface (Bins)
When printing bins:
- PETG for the body (required, per the rule above)
- PLA acceptable as the support interface material — it’s removed before shipping and never contacts the stored coins, so it doesn’t pose a tarnish risk
This is why AMS (or equivalent multi-material capability) is required to produce bins — you need to print the PETG body with PLA support interface in a single job.
Not Acceptable
- ❌ PLA as a body material on any product
- ❌ PLA+ as a body material (still PLA-based)
- ❌ Resin prints (chemical exposure concerns and finish inconsistency)
- ❌ Any material not on the approved list, without prior Coinfinity approval
Print Settings
For printing settings, orientation, supports, and per-product instructions, refer to the public Coinfinity documentation: coinfinitydocs.com/docs/printing-guide.
The public docs cover everything a manufacturer needs to print successfully. This page only documents the additional sourcing constraints that apply to authorized resellers.
When in Doubt
If you’re considering a material not listed here, contact Coinfinity before using it on a product carrying our name or attribution: info@coinfinity.us
It’s much cheaper to ask than to ship a batch that violates standards and has to be reworked.