Ice Mold & Expandable Chamber β CAD Design
Mold Interior
120Γ120
Γ 100 mm depth
Wall Thickness
4 mm
FDM-optimised
Draft Angle
3Β°
all vertical surfaces
Relief Hole
Γ18 mm
balloon stem
Chamber
Γ70β50
65 mm deep conical
Downloadable STL Files
All files are generated on-demand and ready for FDM/SLA 3D printing. Recommended material: PETG or ASA.
Mold Shell
β¬ STL
Outer box with draft, 4mm walls
Lid with Relief Hole
β¬ STL
Γ18mm hole for balloon stem pass-through
Balloon Chamber Form
β¬ STL
Conical guide, Γ70β50mm, 65mm deep
Print Settings: PETG/ASA Β· 0.15mm layer Β· 20% infill Β· 4 perimeters Β· No supports needed
Chamber Design Rationale
Why balloon-based? After evaluating three approaches (rigid two-part mold, silicone bladder, balloon-based), the balloon approach was selected for end-users because:
- No silicone casting equipment required
- Readily available food-grade silicone balloons
- Easy extraction β deflate and pull
- Accommodates 9% water expansion during freezing
Draft angles (3Β°) on all vertical walls ensure the ice block releases cleanly without the mold cracking.
Wall thickness (4mm) is optimised for FDM printing β strong enough to contain water pressure without warping.
Assembly Instructions
Glass Downstem & Tubing Component Design
Cross-Section Assembly Drawing
Thermal Stress Analysis
Tolerance Specifications
Bottom Ice Buffer β Melt Time Estimates
Downstem β Engineering Detail Drawing
Bowl / Slide β Engineering Detail Drawing
How to Fill the Mold & Establish the Balloon Cavity
How to Use β Removable Bowl / Pull-to-Clear Mechanism
The bowl is a removable slide β it friction-fits onto the 14 mm male ground-glass joint at the top of the downstem. No tools, no threading; a light push seats it, a firm pull removes it.
- Load β pack herb into the bowl funnel. The stainless screen in the Γ5 mm floor hole prevents ash from entering the downstem.
- Light & inhale β with the bowl seated, draw slowly. Smoke travels down through the downstem, into the water/ice chamber, and up to your mouth.
- Clear β while still inhaling, pull the bowl straight off the downstem joint. This opens an unrestricted air path, flushing the smoke chamber in one breath. (This is the standard "pull-to-clear" or "carb-pull" method used on all joint-style bongs.)
- Re-seat β push the bowl back onto the joint for the next draw.
Joint standard: 14 mm ground-glass (GG14). Replacement bowls from any headshop or online supplier using a 14 mm female socket will fit directly.
Materials Strategy β Silicone-First for Inexpensive Manufacturing
To minimise unit cost, the design prioritises platinum-cured food-grade silicone wherever glass is not strictly required for heat resistance or aesthetics:
| Component | Standard spec | Budget alternative | Est. saving / unit |
|---|---|---|---|
| Bowl / Slide | Borosilicate glass (~$4β8) | Platinum-cured silicone bowl β injection-moulded, same 14 mm female socket (~$0.80β1.50) | ~$3β6 |
| Mouthpiece tube | Already silicone β | No change needed | β |
| Downstem | Borosilicate glass (flame resistant) | Keep glass β silicone cannot handle direct flame proximity at joint | β |
| Mold shell & lid | PETG 3D-print or ABS injection | Silicone mold β 2-part pour mold, easier demould, reusable (>200 cycles) | ~$2β5 at volume |
| Water-cavity balloon | Already food-grade latex or silicone β | No change needed | β |
Note: Silicone bowl is the biggest cost lever β a standard 14 mm silicone bowl (widely available in bulk from US/EU silicone moulders) drops the per-unit BOM cost by ~$4β6 with zero functional compromise. The mouthpiece tubing (Γ24 mm OD / Γ18 mm ID) is already specified as platinum-cured silicone for both safety and cost reasons.
Mold Shape Variants β Outer Profile Options
Component Specifications
Materials Specification & Food-Grade Compliance
Total Materials
β
BOM line items
Compliance
FDA Β· EU Β· NSF
all food-contact items
Silicone Type
Platinum-cured
addition-cure only
Glass
Borosilicate
Type I, 3.3 CTE
Manufacturing Plan & Cost Estimation
Cost Summary
Batch size:
Contract Manufacturers
Itemised Bill of Materials
| Item | Category | Unit Cost | Proto Qty | Proto Cost | Per Unit (batch) |
|---|
Assembly Sequence
Minimum Viable Product β Eco-Friendly Novelty Version β»
Concept: A bare-bones, eco-friendly kit that delivers the core experience 2β3 times using off-the-shelf parts.
No 3D printing, no silicone casting β just source, pack, and ship.
The waxed cardboard box is both the ice mold and the retail packaging.
Target retail: $27.99 | Net profit (direct): β₯50%
Product & Packaging Rendering β 2D Photo-Realistic Illustration
Loading rendering...
MVP Component Design β Assembly Cross-Section
Loading component design...
Variant Option: 3D-Printed Ice Box (PETG/PLA) β Premium MVP
Same glass and silicone components as the cardboard MVP, but the waxed cardboard ice mold is replaced with a 3D-printed PETG/PLA box. Reusable 10β20 freeze cycles, better water seal, and a premium feel. Suggested retail $34.99 β still β₯52% net margin.
Component Diagram
Loading diagram...
Variant Specs
Loading specs...
Bill of Materials
Batch:
units
| Component | Category | Unit Cost | Per Unit | Supplier |
|---|
Margin Analysis
Eco-Friendly Design Choices
- FSC cardboard box β replaces 3D-printed PETG mold. 100% recyclable, doubles as packaging (zero extra packaging material).
- Natural latex balloon β replaces silicone bladder insert. Biodegradable natural rubber.
- Off-the-shelf glass β no custom fabrication. Standard 14mm headshop components reusable indefinitely.
- Reusable silicone mouthpiece β platinum-cured, food-safe, washes clean for re-use across multiple ice blocks.
- Recycled paper instruction insert β soy-based ink, FSC certified.
Component Specifications
Assembly & Use Instructions (8 Steps)
Manufacturing & Supply Chain Recommendations β MVP Build
Sourcing Strategy
| Component | Recommended Source | MOQ | Notes |
|---|---|---|---|
| 14mm Glass Downstem (4") | Alibaba / DHgate β "14mm diffused downstem" | 50β100 pcs | ~$0.80β1.20/ea; test 5 samples first |
| 14mm Glass Bowl/Slide | Same suppliers as downstem β bundle order | 50β100 pcs | ~$0.60β1.00/ea; borosilicate required |
| Silicone Mouthpiece Tube (25mm OD) | US: McMaster-Carr #5236K51; CN: Yuyao silicone tubing | 10 ft / 3 m | FDA Platinum-cured; cut to 80mm lengths in-house |
| 11" Latex Balloons | Qualatex / Amazon bulk (biodegradable) | 144 pcs/bag | ~$0.08/ea; natural rubber, food-safe |
| Waxed Cardboard Box | PackagingSupplies.com or local box supplier | 250 pcs | ~$0.35β0.50/ea; 130Γ130Γ115mm; waxed interior |
| Silicone O-rings (optional upgrade) | Apple Rubber or ParkerStore | 25 pcs | FDA 70A Shore; stock # 2-116 for 10mm ID |
Assembly & Fulfillment
Batch 1β500 units (bootstrapped):
- Hand-assemble kits in-house or via a small co-packer
- Cut silicone tubes to 80mm using a mitre box jig (β€2 min/unit)
- Kit: box + balloon + downstem + bowl + mouthpiece tube + QR instruction card
- Use a heat-seal pouch for glass components (protects in transit)
Batch 500+ units (outsource):
- 3PL: ShipBob, Whiplash, or a local fulfillment center with cold-storage capability
- Co-packer: seek a nutraceutical or novelty kitting facility (handles fragile SKUs)
- Glass import: consolidate into 20' FCL from Shenzhen at ~500+ units to cut freight 40%
- Box: switch to die-cut setup with printer at 1,000+ units β drops cost to ~$0.28/ea
MVP Launch Timeline
| Week | Milestone |
|---|---|
| 0β1 | Order 10-pc glass sample set from 2 Alibaba suppliers |
| 1β2 | Validate fit: downstem diameter, balloon inflation clearance, mouthpiece seal |
| 2β3 | Place 100-pc glass order; order balloon bulk bag; source boxes |
| 3β4 | Prototype 5 full kits; do freeze test & smoke test; photograph for listing |
| 4β5 | Kit 100 units; list on Shopify/Etsy/Faire; ship first orders |
| 6+ | Review returns/feedback; iterate box size or tube length if needed |
Risk & Mitigation
| Risk | Likelihood | Mitigation |
|---|---|---|
| Glass breakage in transit | Medium | Individual heat-seal pouch + rigid box; mark "fragile" |
| Balloon fails during freeze | Low | Qualify 11" Qualatex; test 5 freeze/thaw cycles before launch |
| Box leaks when wet | Medium | Interior wax coat; add "freeze before removing box" instruction |
| Downstem fit variance | Medium | Order from 2 suppliers; measure OD on arrival; 14.0Β±0.2mm spec |
| Import delay (>4 wks) | LowβMed | Keep 2-wk safety stock; source balloon + box domestically |
Tip: The highest-leverage cost lever at MVP scale is negotiating glass components as a single SKU bundle (downstem + bowl from the same factory). Bundling typically drops per-unit cost 15β25% vs. separate orders and reduces incoming inspection effort.
Premium vs MVP β Side-by-Side Comparison
| Feature | Premium Version | MVP Version β» |
|---|---|---|
| Ice Mold | Custom 3D-printed PETG shell (reusable 50+ times) | Waxed FSC cardboard box (2β3 uses; doubles as packaging) |
| Chamber Former | Platinum-cured silicone bladder | 11" natural latex balloon (biodegradable) |
| Bowl / Slide | Custom 18mm OD borosilicate slide | Standard 14mm off-the-shelf glass slide |
| Downstem | Custom 14mm / 110mm diffused, 45Β° angle | Standard 14mm / 4" (100mm) diffused downstem |
| Mouthpiece | Platinum-cured silicone, 24mm OD, angled 8Β° | Same silicone tube, pre-cut 80mm (same material) |
| O-Rings / Seals | 2Γ FDA silicone O-rings (precision grooves) | None (balloon cavity + tube friction fit) |
| Packaging | Separate retail box + foam insert | The cardboard mold IS the packaging |
| COGS (batch 100) | ~$18β22/unit | ~$7β9/unit |
| Retail Price | $75β90 (suggested) | $27.99 |
| Net Margin (direct) | ~60β65% | β₯55% |
| Mold Lifespan | 50+ freeze cycles | 2β3 freeze cycles |
| Assembly Time | ~20 min | ~5 min |
| Target Market | Enthusiasts, gifts, regular use | Novelty, events, eco-conscious, first-time buyers |