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Comment by kbelder | Hacker News Reader

I don't know firsthand whether this is true, but this is an old family story about my Grandfather.

He was a logger in the Pacific Northwest. At one point he was hauling logs up the Oregon Coast, and his truck broke down in the middle of nowhere, stranding him. (Probably an old Gary truck, which was practically made from cast iron.) I don't remember the exact part, but it was something to do with a wheel... the rim, or part of the axle or mounting.

He happened to have some ingots in his truck (a soft metal, I forget the term). So he built up a large fire, melted the ingots, and sand-cast a replacement part using the broken piece as a template. Once it cooled and was cleaned up, it worked well enough to get him to civilization, or whatever passed for civilization in Oregon in the 30s.

Seeing all the logging hacks I've seen when growing up, I completely believe this story.

View on HN

Specs of Gary Trucks, which may be of interest to other automotive nerds [0].

I particularly like how the base trim provides splash based oil lubrication only.

[0] https://static.wikia.nocookie.net/mycompanies/images/f/ff/Ga...

Honestly that's super impressive. Sand casting can be difficult to get right. The metal was likely aluminum? Did he use motor oil to wet the sand?

I don't think it was aluminum because he mentioned it was during the '30s. I believe it wasn't as widespread as it is nowadays

For 1930s, I'd assume that lead is much common than aluminum, and it's also much easier to melt.

Most likely it was Babbit. Which is... possibly feasible for someone to be carrying back then. As it could have been used(in a pinch) to repour bearings in the field. Or maybe he was simply just carrying lead for weights used for getting lines up into trees.

https://en.wikipedia.org/wiki/Babbitt_(alloy)

I'd think https://en.wikipedia.org/wiki/Pot_metal

Aluminum is easy to cut, but not melt — twice the melting point of lead, and hard to achieve without knowing what you’re doing.

No, aluminum melts at 1.55 times the melting point of lead, and I've melted aluminum many times by accident, even 1000-series aluminum.

> No, aluminum melts at 1.55 times the melting point of lead

I guess it depends on your definition of "double" -- Al @ 1221°F / 660°C vs. Pb @ 621.5°F / 327°C, but sure, in Kelvin it's 1.55 thanks to the higher baseline. Still ~twice the delta-T from room temp, though.

> I've melted aluminum many times by accident, even 1000-series aluminum.

Really? With a wood-based fire?

It only depends on using a coherent definition of "double". It doesn't make sense to multiply and divide temperatures measured in °F or °C; those are interval scales, not ratio scales. In the US men's shoe size 3 is 9.25 inches long, and shoe size 12 is 12.25 inches long. Would you say that size-12 feet are four times as long as size-3 feet? Multiplying and dividing temperatures measured in °F or °C is the same error. (Multiplying and dividing ΔT measured in °F is fine, though.)

It's easy enough to melt 1000-series aluminum foil with a wood fire, and people commonly melt parts of beer cans in wood fires as well (ten times thicker but with a lower melting point). Aluminum ingots usually require at least a charcoal fire, and usually forced-air convection as well. But, as someone commented in another thread, babbitt is a much more likely candidate for the metal in question, because why would a logger be carrying around aluminum ingots in their truck? Especially in the 01930s. Ingots are for remelting, and that's a sensible thing to do in the field with babbitt in a non-emergency situation, much less so with aluminum.

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