driftwest.xyz · garage engineering

🌭 The 12V Hot Dog Forge

An insulated cigarette-socket cooker that turns a parked 2003 Grand Caravan into a roadside hot dog stand. Here's the math, the CAD, and the exact parts.

~110 W

design power

~9 A

at 12 V (10 A fuse)

5–6 min

per dog (cold tube)

12–15

dogs before van won't start

Run the engine and the alternator (~1000 W+) swallows the 110 W draw — unlimited dogs at idle. Parked, you're spending the starting battery: ~12–15 dogs with confidence, ~25 if you gamble on an old battery (keep jumper cables aboard).

FIG 1 Cutaway

⬇ hotdog-forge.scad — parametric CAD (OpenSCAD) ⬇ hotdog-forge.svg — section drawing

The .scad is a real editable CAD model — open it free in OpenSCAD, change a parameter, press F6, and Export → STL to 3D-print the shell and end caps.

BOM Parts list — tap to shop on Amazon.ca

Nine parts. Each tile runs a tuned Amazon.ca search for that exact spec — opens cleanly in either the Amazon app or a browser, lands on live Canadian listings with current prices and stock. Search beats fixed ASINs here: products go out of stock, but a search always returns something current. Sort by price-low for the cheapest match.

⚠️ Heater pad — read this before tile #1. Most "12V silicone heater pads" on Amazon are reptile / pipe / seedling mats with a built-in PTC self-limiter that caps at 65 °C — those will only warm a hot dog, not cook it. You want a 3D-printer heated-bed pad: same form factor, no self-limiter, reaches ~180 °C. Our 90 °C thermostat disc then does the regulation. Tile #1 is now tuned for that — the magic words in the search are "3D printer heated bed".

Best size for our 1" tube: roughly 100×100 mm (4"×4") or 100×150 mm — wraps the barrel once with no overlap (overlap = hot spot, scorched element). Anything bigger than 6" wide you'll have to trim or fold (don't fold — see above).

1 · ~$18Silicone heater pad12V 100W 3D-printer bed (reaches 180°C — avoid reptile/pipe pads capped at 65°C) 2 · ~$11Aluminium barrel25 mm ID (≈1") × ~200 mm 3 · ~$8Thermostat discKSD9700 90°C NC, 10A (not 5A!) 4 · ~$7Thermal fuseOne-shot 120°C 10A 250V 5 · ~$9Plug + switch + fuse12V male, 10A fused, switched 6 · ~$13Insulation wrapFiberglass heat wrap, 1" wide 7 · ~$11High-temp wire16 AWG silicone 200°C, red+black 8 · ~$8Kapton tapePolyimide 1" × ~36 yd 9 · ~$9End caps1" ID silicone, high-temp (≥500°F)

Estimated build total: ≈ $91 CAD · real single-build cost ≈ $60 (rest is multipack spares)

📱 Works in the app or the browser. Search URLs survive the Amazon app's deep-link handler, unlike cart-add links — tap any tile and you'll land on real Amazon.ca results, no country-switch prompt, no empty cart.

🇺🇸 Stateside? Same searches work on amazon.com — just swap amazon.ca for amazon.com in the URL.

WIRE Safety chain

12V+ (plug, 10A fuse)
  └─ switch
     └─ thermal fuse        120°C one-shot   ← physically cannot run away
        └─ bimetallic disc  90°C NC          ← everyday on/off regulation
           └─ heater pad +
heater pad − ─────────────── 12V− (plug ground)

LED + resistor across heater terminals = "cooking" light

The disc does the day-to-day temperature cycling (~70–90°C). The thermal fuse only ever blows if the disc fails closed — that one part is why this can't melt or burn. Don't omit it.

BUILD Assembly notes

Mount the thermostat disc tight against the aluminium barrel (sense metal, not air). Thermal fuse right beside it.
Wrap the heater pad evenly — no overlap, no air gaps → no hot spots.
Insulation goes outside barrel+heater, then the outer shell. Leave a small vent or steam pressure will pop the end cap.
Dry-test first (no dog): confirm the disc cycles and the tube stabilises ~85–90°C and isn't climbing. Over-temp test the thermal fuse separately before you trust it.
Then a dog: ~5–6 min from cold, ~3–4 min if the tube's still hot from the last one.

🌭 driftwest.xyz/hotdgger — built by Sparky · not a certified appliance, cook at your own risk · driftwest.xyz