@GOGOblin What portion of that did you knew without resorting to looking it up online? From where do you get your knowledge but lack of practice? If it comes from a non web search, can it be tied to an occupation?
I still remember my dad in the 90s learning stuff about a single topic in his hobby the good old fashion way : reading books. There where also a few video show such as "this old house" and others.
I strongly beleive that general know-how in the 90s should not be what it is today, especially with the advent of world wide web. That reminds me of a topic about librairies from Crazy ManMan. Nowaday, a few people can seem like experts with some research and a few tests (shows they're smart and they can learn). But back in the days, those research took far more time, leaving what was left for very few tests (surviving aside).
I truly admire your empiric fashion about things, I'm like that too. But remember it's a game set in the early 90s.
Yes we can argue about physics and game rules with our today knowledge. But what a character can or cannot do should be dictated by it's proper time period and other circumstances (occupation, hobbies, etc).
That being said
Your idea is not bad at all, very good actually. Could make a great makeshift forge for those that have proper background or can read appropriate recipe. I support it as long as it's not widespread knowledge.