Re: Pot metal - was something else

On Sun, 9 Aug 2026 13:20:36 +0100, The Natural Philosopher wrote:

> 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

Thermosets are cross-linked and more stable than thermoplastics.

https://en.wikipedia.org/wiki/Thermosetting_polymer

The systems I worked with used thermosetting compounds, typically 
phenolic, expoxy, melamine, or furan.  The last was a stopgap measure. The 
oil embargo had a great impact on the petrochemical industry and material 
was difficult to source. Furan is based on furfural, typically produced 
from corncobs. Like most stopgaps it didn't have the strength of phenols 
or epoxies, The flow characteristics were different and moldmakers had to 
adapt. 

Thermoplastics are a different animal. I worked briefly for a company that 
made polystyrene foam disposable dinnerware. One advantage of 
thermoplastics is you can regrind your mistakes. The blowing agent was 
Freon-12 and the company bought it by the railway tank car. That's another 
'was' company on my resume, to say nothing of the CFC process.