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Casting a Model Westinghouse-Type Twin Steam Engine in Iron

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vtsteam:
Andrew, I've actually got instructions for making one of those, which I downloaded awhile ago. I haven't made it yet.

But there's also the Terry Aspin method, which actually works if you pay attention to it strictly (I didn't this last melt because of a dumb belief that it had taken so long it MUST be ready) And that is, just look at your 1/4" dia steel stir stick. If you give the pot a poke or stir and there's a glob of slag or metal stuck to the end, it's not ready. If it comes out perfectly clean and coming to a sharp point like a pencil because it melted a little, well, time to pour!

Steel melts at a bit higher temp than iron, so it's a simple perfectly straightforward thermometer. You do have to pay attention to it though, for it to work. :wack:

tom osselton:
That’s what it says to check the temp in the metal casting bible by C.W.  Ammem

vtsteam:
I had a point and a gob. Shoulda just been a point. I now think the point was from the prior melt. Gob shoulda melted off, point shoulda been shiny and sharp
Lesson learned: No gobs, period.
 :smart:

ironman:
[quote author=vtsteam link=topic=13496.msg162471#msg162471 date=1
If it comes out perfectly clean and coming to a sharp point like a pencil because it melted a little, well, time to pour!
Steel melts at a bit higher temp than iron, so it's a simple perfectly straightforward thermometer.
[/quote]
A low carbon steel rod will quickly absorb carbon from molten cast iron and it will lower the melting point so that is the sharp point that appears after 10-20 seconds  of stirring. If you hold that stirring rod above the crucible for 10-20 seconds it will not melt because the flame temperature is not hot enough. I do have a R type pyrometer and the final temperature before pouring is 1550C-1570C above the crucible which is just above the melting point of a low carbon steel.

vtsteam:
Ahhh, interesting, Ironman, so you're saying that the best place to check (without a pyrometer) would be just above the crucible, rather than stirring the molten iron itself.

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