Re: Pot metal - was something else
The Natural Philosopher <[email protected]>
| Newsgroups | comp.os.linux.misc,comp.sys.raspberry-pi |
|---|---|
| Organization | A little, after lunch |
| Message-ID | <[email protected]> |
On 09/08/2026 14:06, Carlos E.R. wrote: > On 2026-08-09 14:20, The Natural Philosopher wrote: >> On 09/08/2026 01:47, c186282 wrote: >>> The alloy does not seem very resistant to vibration. >>> It's soft enough you'd THINK it would be, but its not. >>> >> The problem is mainly that its has no fixed composition, Its random >> non ferrous scarp mainly. Use a magnet to get the iron and steel and >> melt what is left over perhaps >> >> >>> Most aluminum alloys and 300 series stainless are >>> not super-good with vibrations either - though >>> better than 'pot metal'. I've seen 'magnesium' tire >>> rims crack too. >>> >> Pot metal is heavy and brittle in my experience. >> >> Came across it back in the day in toys, carburettor castings, >> thermostat housings..valve covers..all stuff that needed shape >> retention but no great strength >> >>> Only steel - esp nearly pure iron - seems to stand >>> up to vibration, but it's HEAVY. Some cast iron, >>> like that previously used for engine blocks, can >>> be pretty good but will fracture on a sharp impact. >>> I've seen old cracked engine blocks too. >>> >> Cast iron is brittle.That's why they used to use wrought iron - but it >> was expensive. >> Then making steel got super cheap and that was that. Whole generation >> learned to treat and alloy steel to get almost whatever you want >> >>> Plastics - they start 'crystalizing'/decomposing >>> the instant they're made. >> >> Not all of them. Like steel, there is a huge range. There's many a >> radio case made of 'Bakelite' or stuff skinned with 'Formica' or >> floored with 'linoleum'....still functioning >> >> Epoxy and glass fibre PCBs dating from the 1970s are still OK, as are >> phenolic resin items >> >> PVC however is very short lived, In the sun > > PVC is used here for window frames and blinds. I had a place with such, > 40 year old, and good. Yellowish, though. And more brittle. > That's UPVC - treaqted to reduce the effect, but not eliminate it >> >> Nylon is intermediate - UV ageing often gets it >> >> Jury is still out on polycarbonate, ABS and ASA. >> >> In fact one of the eco gripes about plastics is that they *don't* >> degrade. > > They fragment into microplastics. > >> >> Nevertheless there are plastic gobbling bugs thriving at the bottom of >> the sea apparently, eating all those microplastics. >> >> Beware the SweepingStatement... >> >> >> > > -- “It is dangerous to be right in matters on which the established authorities are wrong.” ― Voltaire, The Age of Louis XIV