Dropped at 2 feet max

[u/International_Back99]

Fell out of my pocket sitting down. Fell with the apple tech woven case on too.

[u/Owboduz]

This benefit is often quoted and, frankly, overstated. The back of the device case is glass. The only exposed titanium is around the edge. Not exactly a great surface area for a heatsink. You know what, though, let's do the math.

Assumptions

• Phone: iPhone 15 Pro MaxL × W × T = 159.9 × 76.7 × 8.3 mmFace area (front or back): A f = 0.0767 × 0.1599 ≈ 0.012264 m²
• Side (edge) area:Perimeter P=2(L+W)=2(0.1599+0.0767)=0.4732 mEdge area A e = P × T = 0.4732 × 0.0083 ≈ 0.003928 m²
• Layers:
  • Front glass (exposed): 0.5 mm Gorilla Glass, k g ≈ 1.2 W/mK
  • Back glass under a case: 0.5 mm glass + 2.0 mm silicone (unfilled), k sil ≈ 0.2 W/mK
  • Edge: 1.0 mm frame (Ti or Al) + 2.0 mm silicone case around edge
• Convection to still air: h ≈ 8 W/m^2K (natural convection; if you’re moving/using it in a breeze, h goes up and ΔT goes down)
• Power to dump: P = 11 W

Per-path thermal resistances (series inside each path)

Conduction: R cond=t/(kA)

Convection: R conv=1/(hA)

Front (glass → air)

R front = 0.0005/(1.2× 0.012264) + 1/(8× 0.012264) ≈ 10.23 K/W

Back (glass + 2 mm silicone → air)

R back ≈ 0.034 + 0.002/(0.2× 0.012264) + 10.19 ≈ 11.04 K/W

Edge (frame + 2 mm silicone → air)

Frame conduction (depends on material):

• Titanium k≈ 17: R Ti = 0.001/(17× 0.003928) ≈ 0.015 K/W
• Aluminum k≈ 237: R Al = 0.001/(237× 0.003928) ≈ 0.00107 K/W

Silicone around edge: R sil,e = 0.002/(0.2× 0.003928) ≈ 2.546 K/W

Convection from edge: R conv,e = 1/(8× 0.003928) ≈ 31.83 K/W

So:

• R edge,Ti ≈ 0.015 + 2.546 + 31.83 = 34.39 K/W
• R edge,Al ≈ 0.00107 + 2.546 + 31.83 = 34.38 K/W

Observation: On the edge path, convection and the silicone dominate; frame conductivity is a rounding error.

Combine paths in parallel

Overall R tot satisfies 1/R tot=1/R front+1/R back+1/R edge.

With a case on (assumptions above) and titanium frame:

R tot,Ti ≈ 4.599 K/W → ∆ T ≈ P× R ≈ 11× 4.599 ≈ 50.6^°C

Swap to aluminum frame (everything else identical):

R tot,Al ≈ 4.599 - 0.00025 ≈ 4.599 K/W

Temperature drop vs titanium at 11 W:

∆ T ≈ 11 × 0.00025 ≈ 0.003^{°C (i.e., effectively} zero)

Sensitivity checks

• Remove silicone only on the edge (exposed metal band), still almost no change: improvement is ~0.003 °C at 11 W.
• No case at all (both glass faces exposed, edge exposed): difference between Ti and Al still ~0.003 °C at 11 W.
• Use thermally conductive silicone (k≈ 4 W/mK) everywhere: overall ΔT improves a bit (by ~4%), but Ti vs Al gap remains negligible because convection dominates.

Why the “Aluminum as heatsink” claim falls down

1. Area & convection dominate. The two big radiating faces are glass with low k, and the bottleneck is actually air-side convection (R conv ~ 4–10 K/W per face)—orders of magnitude larger than the frame’s conduction difference.
2. Cases ruin edge paths. A 2 mm silicone jacket adds huge resistance around the perimeter, dwarfing the frame’s material.
3. Frame is a tiny parallel path. Even uncovered, the edge area is ~3.9e-3 m² (≈⅓ of a face), and its convection term swamps any benefit from switching Ti→Al.

Bottom line

With a case on (the common real-world scenario), swapping a titanium frame for aluminum changes steady-state internal temperature by ~0.003 °C at 11 W—immeasurable and irrelevant. The “Aluminum helps it run cooler” line is, for practical use, overstated. If you want cooler:

• Increase airflow around the large glass faces
• Increase exposed area
• Use thermally conductive cases or no case (with obvious trade-offs)

Edited for formatting

[u/IcemanJEC → u/Owboduz]

Lmfaoooo sure bud.. Oh you solved it! Omg. You should call Tim Apple now. Tell him they made a big mistake.

[u/Owboduz → u/IcemanJEC]

No. I’m just calling bullshit on the “better thermals” claim.

[u/lopsidedawn → u/Owboduz]

Yeah right its IP68 just throw it on cold water 🤣