Materials and Safety

Chapter 3: Choosing the Right Plastics

Food Safety First

When 3D printing anything that contacts food or beverages, material selection is critical. Not all filaments are created equal.

Primary Material: PCTG

After extensive research and testing, PCTG (Polyethylene Terephthalate Glycol-Modified) emerged as the ideal choice:

Why PCTG?

Chemical resistance to coffee acids
Temperature stability up to 80°C+
FDA approved formulations available
Clear printing for visual inspection
Low moisture absorption

PCTG Specifications

Glass transition: 80°C
Print temperature: 245-260°C
Bed temperature: 70-80°C
Chemical formula: (C10H8O4)n

Gasket Material: TPE/TPU

The NoDrip XL uses an optional TPE disc gasket for improved sealing:

Options Tested

TPU 95A - Good flexibility, difficult adhesion
TPE 85A - Excellent seal, tricky to print
Silicone - Ideal properties, requires casting

Final Choice: TPE Disc Gasket

Designed as a separate disc for easy replacement
Shore hardness ideal for sealing
No-drip performance when properly installed
Food-safe formulations available
Optional component (cap works without it)

Materials to Avoid

Never Use

ABS - Releases harmful fumes, not food-safe
Standard PLA - Degrades with heat and moisture
Nylon - Absorbs water, affects coffee taste

Use with Caution

PETG - Similar to PCTG but less chemical resistant
PP - Difficult to print, may warp
PC - Requires very high temperatures

Surface Finish Matters

Layer Adhesion

Proper temperatures ensure no gaps
Avoid under-extrusion at all costs
Consider 110% flow rate for solid walls

Post-Processing

Sanding - Removes layer lines
Vapor smoothing - Not recommended for PCTG
Food-safe coating - Optional but adds complexity

Testing for Safety

Visual Inspection

Check for gaps between layers
Ensure no stringing or blobs
Verify smooth internal surfaces

Water Testing

Submerge in hot water (90°C) for 10 minutes
Check for deformation or degradation
Inspect for any discoloration

Practical Testing

Brew with water only first
Check for any off-tastes
Monitor for degradation over time

Sourcing Materials

Recommended Brands

Prusament PCTG - Consistent quality
FilamentOne PCTG - Good clarity
NinjaTek Chinchilla - Excellent TPE

What to Look For

FDA compliance statements
MSDS availability
Consistent diameter (±0.02mm)
Proper storage (sealed, dry)

Storage and Handling

Filament Storage

Sealed containers with desiccant
Print directly from dry box if possible
PCTG: <20% humidity ideal

Printed Parts

Wash with dish soap before first use
Store dry between uses
Replace if any degradation appears

The Microplastics Question

This deserves its own chapter — see Chapter 6 for a detailed discussion of microplastic concerns and mitigation strategies.

Various printed caps in different materials showcasing the evolution

Key Takeaways

PCTG is the optimal choice for the main body
TPE provides excellent gasket properties
Surface quality matters as much as material
Regular inspection ensures continued safety

Next, we’ll dive into the actual printing process and settings that make it all work.

--- title: "Materials and Safety" --- # Chapter 3: Choosing the Right Plastics ## Food Safety First When 3D printing anything that contacts food or beverages, material selection is critical. Not all filaments are created equal. ## Primary Material: PCTG After extensive research and testing, PCTG (Polyethylene Terephthalate Glycol-Modified) emerged as the ideal choice: ### Why PCTG? - **Chemical resistance** to coffee acids - **Temperature stability** up to 80°C+ - **FDA approved** formulations available - **Clear printing** for visual inspection - **Low moisture absorption** ### PCTG Specifications ``` Glass transition: 80°C Print temperature: 245-260°C Bed temperature: 70-80°C Chemical formula: (C10H8O4)n ``` ## Gasket Material: TPE/TPU The NoDrip XL uses an optional TPE disc gasket for improved sealing: ### Options Tested 1. **TPU 95A** - Good flexibility, difficult adhesion 2. **TPE 85A** - Excellent seal, tricky to print 3. **Silicone** - Ideal properties, requires casting ### Final Choice: TPE Disc Gasket - Designed as a separate disc for easy replacement - Shore hardness ideal for sealing - No-drip performance when properly installed - Food-safe formulations available - Optional component (cap works without it) ## Materials to Avoid ### Never Use - **ABS** - Releases harmful fumes, not food-safe - **Standard PLA** - Degrades with heat and moisture - **Nylon** - Absorbs water, affects coffee taste ### Use with Caution - **PETG** - Similar to PCTG but less chemical resistant - **PP** - Difficult to print, may warp - **PC** - Requires very high temperatures ## Surface Finish Matters ### Layer Adhesion - Proper temperatures ensure no gaps - Avoid under-extrusion at all costs - Consider 110% flow rate for solid walls ### Post-Processing 1. **Sanding** - Removes layer lines 2. **Vapor smoothing** - Not recommended for PCTG 3. **Food-safe coating** - Optional but adds complexity ## Testing for Safety ### Visual Inspection - Check for gaps between layers - Ensure no stringing or blobs - Verify smooth internal surfaces ### Water Testing 1. Submerge in hot water (90°C) for 10 minutes 2. Check for deformation or degradation 3. Inspect for any discoloration ### Practical Testing - Brew with water only first - Check for any off-tastes - Monitor for degradation over time ## Sourcing Materials ### Recommended Brands - **Prusament PCTG** - Consistent quality - **FilamentOne PCTG** - Good clarity - **NinjaTek Chinchilla** - Excellent TPE ### What to Look For - FDA compliance statements - MSDS availability - Consistent diameter (±0.02mm) - Proper storage (sealed, dry) ## Storage and Handling ### Filament Storage - Sealed containers with desiccant - Print directly from dry box if possible - PCTG: <20% humidity ideal ### Printed Parts - Wash with dish soap before first use - Store dry between uses - Replace if any degradation appears ## The Microplastics Question This deserves its own chapter — see Chapter 6 for a detailed discussion of microplastic concerns and mitigation strategies. ![Various printed caps in different materials showcasing the evolution](images/IMG_0050.jpeg) ## Key Takeaways 1. **PCTG** is the optimal choice for the main body 2. **TPE** provides excellent gasket properties 3. **Surface quality** matters as much as material 4. **Regular inspection** ensures continued safety Next, we'll dive into the actual printing process and settings that make it all work.