Pick the wrong plastic and your dish soaks up water, softens at warm shower temperatures, and ends up in the trash. Pick the right one, tune your walls and infill, and design in real drainage, and you get a soap dish that lasts years.
This guide covers the filaments that actually work, the settings that make prints watertight, and the free models worth printing.
- PLA is water-resistant, not waterproof. It absorbs water, softens at shower temperatures, and fails in soapy environments within weeks to months.
- PETG is the best all-around choice for a 3D printed soap dish. It absorbs about 8 times less water than PLA and holds up to 80°C before softening.
- TPU works great for non-slip pads and grips on the bottom of a dish, but is not needed for the full body.
- Drainage beats waterproofing every time. A slatted or sloped design lets water run off so the plastic barely gets wet in the first place.
- Use at least 4 walls, 20% infill, and a 0.6mm line width for watertight prints.
- Skip acetone vapor smoothing. It does nothing to PLA and is risky for PETG.
Why Most 3D Printed Soap Dishes Fail
A soap dish sits in one of the harshest spots in your house. It gets splashed with warm water every day, holds a bar of soap that is alkaline (pH 9 to 10), and lives in humidity that hits 70% or higher when you shower.
Most hobbyists grab a spool of PLA because it is what they have on hand. Then they wonder why their dish warps, smells funny, or grows a pink film of mold after a month.
- Water absorbs into the plastic through tiny gaps between layers and the plastic itself.
- Warm water softens low-heat-tolerance materials like PLA above 55°C.
- Standing water plus organic soap residue feeds bacteria and mold in the layer lines.
- Poor drainage traps soap scum against the print, speeding up breakdown.
PLA vs PETG vs TPU for Soap Dishes: Lab Data
Every filament reacts to water differently. Under the ASTM D570 test (24 hour soak at 23°C), the numbers are clear.
A 2021 peer-reviewed study in Polymers also tested 3D-printed samples in distilled water for 9 weeks. Here is how the three most common bathroom-ready materials stack up.
| Property | PLA | PETG | TPU (95A) |
|---|---|---|---|
| Water absorption (24 hr soak) | 0.5% to 1.0% | 0.1% to 0.2% | 0.3% to 0.5% |
| Water gain at 8 weeks (soaked) | ~2.5% | ~0.3% | ~0.7% |
| Glass transition temp (Tg) | 55°C to 60°C | 80°C to 85°C | Around 80°C |
| Holds up to shower water (38 to 42°C)? | Barely | Yes | Yes |
| Soap (pH 9 to 10) resistance | Poor | Excellent | Excellent |
| Print difficulty (1 easy, 5 hard) | 1 | 2 | 4 |
| Good for soap dish body? | No | Yes | Only for grip pads |
| Typical cost per kg | $18 to $22 | $22 to $28 | $35 to $45 |
Plain English takeaway: PETG absorbs about 8 times less water than PLA over eight weeks and shrugs off shower heat with room to spare.
That is why PETG is the default pick for anything that comes into contact with water in your house, from planters to soap dishes to shower caddies.
What About ABS, ASA, and Nylon?
Short answer: They all work, but they are overkill.
- ABS resists water and heat well, but warps without an enclosure and releases strong fumes.
- ASA is great for outdoor prints and UV exposure. If your soap dish sits on a sunny windowsill, ASA is a smart upgrade over PETG.
- Nylon absorbs more water than even PLA. It swells, warps, and loses strength. Avoid nylon for any wet-environment part unless you seal it.
For 95% of home bathroom projects, PETG wins on cost, ease of printing, and durability.
Slicer Settings That Make a Soap Dish Watertight
Material only gets you halfway there. The other half is how you slice the model.
A PETG soap dish with bad settings will still wick water through the layer lines. Here are the numbers that work, tested across Bambu, Prusa, Elegoo Centauri, and Creality machines.
Recommended Slicer Settings for a Watertight Soap Dish
| Setting | PETG (Recommended) | PLA (If You Must) |
|---|---|---|
| Nozzle temperature | 230°C to 245°C | 205°C to 215°C |
| Bed temperature | 75°C to 85°C | 55°C to 60°C |
| Nozzle size | 0.4mm or 0.6mm | 0.4mm |
| Line width | 0.48mm to 0.6mm | 0.48mm |
| Walls/perimeters | 4 to 5 | 5 to 6 |
| Top layers | 6 | 7 |
| Bottom layers | 5 | 6 |
| Infill | 20% to 30% gyroid | 25% to 35% gyroid |
| Print speed | 40 to 60 mm/s | 50 to 80 mm/s |
| Cooling fan | 30% to 50% | 100% |
| Retraction (Direct Drive) | 1.0mm at 40 mm/s | 1.0mm at 40 mm/s |
Why these numbers matter:
- ✅ More walls slow water down. Water finds its way through tiny gaps between extrusion lines. Every extra wall is another barrier.
- ✅ Gyroid infill holds up better than grid or lines because it has no straight paths for water to wick through.
- ✅ Wider line widths overlap more and leave fewer pinholes. Setting line width to 120% to 150% of your nozzle diameter is an easy win.
- ✅ Lower cooling on PETG and leave fewer pinholes. Setting line width to 120% to 150% of your nozzle diameter is an easy win.gives stronger layer bonds, which means fewer gaps for water.
If your printer supports it, use a 0.6mm nozzle. Thicker extrusions are naturally more watertight and print faster. It is the single easiest upgrade for bathroom prints.
Design Tips That Work
Honestly, the best soap dish is one where water barely touches the plastic at all.
Here is how to design (or pick a model) that stays dry on its own.
- ✅ Add Real Drainage: Look for models with raised slats, ridges, or a hex pattern. The soap rests on thin contact points while water drops through and runs off. If water cannot pool, the plastic cannot absorb it.
- ✅ Slope the Base: A flat base holds water like a tray. A base angled 5 to 10 degrees toward a drain hole moves water off the print in seconds.
- ✅ Elevate the Soap: A dish with a flat bottom and a bar of soap on it will always grow slime. Designs that lift the soap at least 6mm off the water layer last longer and keep the soap lasting longer too.
- ✅ Round the inside corners: Sharp inside corners trap soap residue and mold. Fillets of 2mm or more make cleaning easier.
- ✅ Print a removable top grid: A two-part design with a drip tray and a removable grid is the pro move. You can lift the grid out, rinse both pieces, and dry them weekly. This is the design most commercial silicone and bamboo soap dishes use for a reason.
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How Long Does a 3D Printed Soap Dish Actually Last?
Based on community reports and internal Siraya testing with bar soap and daily use:
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PLA dish with no drainage: 4 to 8 weeks before visible warping or mold.
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PLA dish with good drainage: 3 to 6 months, then it starts to soften.
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PETG dish with good drainage: 2 to 5 years, often longer.
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PETG dish sealed with epoxy: Basically indefinite. People report 5+ years.
The design of your dish matters more than the exact plastic. A well-drained PLA print can outlast a poorly designed PETG one. But if you want to print once and forget about it, PETG with drainage is the move.
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FAQs About 3D Printed Soap Dishes
Is PLA okay for a soap dish?
PLA works short-term but is not a good long-term choice. It absorbs water, softens above 55°C, and breaks down in the alkaline environment created by soap. You will see noticeable warping or softening within weeks to a few months, depending on how much warm water hits it. If you print in PLA, use a design with heavy drainage, and be ready to reprint.
What is the best filament for a 3D printed soap dish?
PETG is the best all-around choice. It absorbs roughly 8 times less water than PLA over 8 weeks of soaking, holds its shape up to around 80°C, and resists soap chemistry well. It costs only a few dollars more per kilogram than PLA and prints on any modern 3D printer with a heated bed. For outdoor or sunny spots, ASA is a solid upgrade.
How do I make my 3D print waterproof?
Start with a water-resistant material like PETG or ASA. Then tune your slicer for watertight walls: use 4 or more perimeters, a line width of 120% to 150% of your nozzle diameter, 6+ top and bottom layers, and gyroid infill at 20% or higher. For guaranteed waterproofing, brush a thin coat of food-safe epoxy over the finished print. Skip wax coatings since they wear off in weeks.
Do 3D printed soap dishes grow mold?
They can if the design traps water and soap residue against the plastic. Mold grows on the organic soap scum, not the plastic itself. You prevent it three ways: pick a design with real drainage slots, rinse the dish weekly with warm water, and let it air-dry once a week. A two-piece design with a removable grid makes this much easier.
Can I put a 3D printed soap dish in the dishwasher?
PLA, absolutely not. Dishwasher temperatures hit 60 to 75°C, which is well above PLA's softening point. PETG can handle a top-rack dishwasher cycle (around 65°C) if your cycle runs on the cooler side, but repeated washes will slowly cloud the surface. Hand-washing with warm water and mild soap is better. If you need dishwasher-safe, cast the dish in platinum silicone instead.
Final Thoughts
A 3D printed soap dish is one of the best beginner-to-intermediate functional prints out there. It takes about 4 to 6 hours to print, uses 50 to 100 grams of filament, and solves a real problem in your house.
The trick is to stop thinking of it as a "print it and hope" project and start treating it like a small engineering job. Pick PETG, print it with thick walls and gyroid infill, and use a design with real drainage.
Do that and your dish will be the last one you need to print.