I have only cast aluminum and lead. Hoping to do cast iron eventually. I segregate my ingots based on what the source metal was. I reserve the high quality stuff for the fine detail castings. Old steam radiators are supposed to be very high quality cast iron.
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Cast Iron Quality in my Foundry (From Brake Rotors)
- Thread starter Xyius
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- cast iron foundry impurities
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- Mar 25, 2013
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The guys I know who do iron try to steer away from brake rotors. They feel the alloy is inferior and inconsistent. Also if you intend to machine your castings you should add some ferrosilicon before pouring. That helps fluidity and to prevent areas of chill which cannot be machined (easily.)
Robert
Robert
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Thanks, I will read this through later tonight.
One of the things I do to mitigate the casting being so hard is leave it in the mold for sometimes 24 hours, to cool VERY slowly. It still ends up being harder than a coffin nail though. But that is actually fine for what I want to use it for, namely, making an engine. I would rather my parts be very hard and difficult to machine, but stand up to wear very well. I have never broken an iron casting out of the mold immediately after solidifying, as I am sure that would lead to something WAAAY harder and more difficult to machine.
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I tend to agree, but as I said above, class 20, 30, 40 gray iron, ASTM A-48 does not govern chemistry, which leaves a big hole to what can be added to the mix. There's also a Automotive SAE specification J431 that covers things like brake rotors, engine blocks, heads and so on which is pretty much the same specification as A-48 but for Automotive use. (Bruce might be able to add to this) In my opinion, the cast iron used to make these parts is to specification and should not be questioned. Now with offshore manufacturing of brake rotors, yes I agree, the cheaper one's I would suspect are not made to specifications but I bet they melt just as good as any other iron out there. There's an art to making iron castings and its not as easy as you would think. Cut up and melt some brake rotors and see what you wind up with. And chill rate is part of the process. Also, the making of the sand mold, too.
One thing a person almost has to have in this business is a Stereomicroscope. This allows you to look at the sample of iron microstructure and determine if it is correct or not.
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Another "iron" that melts good and makes a decent casting is G-2 Dura Bar. You almost don't have to add anything to the melt including Silicon, it has plenty. I have plenty of it on hand if want a piece to play with. Ken
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Interesting videos. I have not done any foundry work in 40 years, and then only aluminum in HS. But since I restore old farm windmills, this definitely has my curiosity up.
Wow so many awesome replies. You guys are great, my first post here as certainly been a positive experience.
I will do that!
I am very intrigued by this. Where can I read up what to look for in the grain structure to determine if the iron is correct or not for casting?
Wow that would be great! I will send you a PM of where to send it to, I can send you a payment through Paypal to pay for the shipping. I need to make some small castings soon and it would be a very fun experiment to use only the Dura bar and see how differently they machine. Thanks!
I will do that!
I am very intrigued by this. Where can I read up what to look for in the grain structure to determine if the iron is correct or not for casting?
Wow that would be great! I will send you a PM of where to send it to, I can send you a payment through Paypal to pay for the shipping. I need to make some small castings soon and it would be a very fun experiment to use only the Dura bar and see how differently they machine. Thanks!