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Lost wax casting and cores?

Hi!

I'm sitting in front of my computer and drawing along for my next project. It's a scale model of a Diesel engine built 1906. Looking at the various parts, I have to lift my hat for the enineers that built it. Even more ingenuity in the shop that built the patterns! The base plate is so complicated that I do have to use lost wax casting (and silicone forms).

Right now, I'm thinking how I could cast the valve head that I have drawn (paper is patient). I _need_ to have core prints in the casting. Is that possible? *) And if yes, how do I make the cores? Do I use the same "plaster" and cure it in a silicone form? Can I stiffen the core print with some (SS) wire?

*) I have to admit, that I do have _very_ little casting experience and I know that I will have to learn a lot. If I can't handle it by myself, I will give my wax prints to a shop.

TIA Nick

PS: Small fittings will be made spinncasted in zinc. Thanks for the tips/links I got that for!

Reply to
Nick Müller
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Hey Nick,

Wish I could help with your question, but I can not. I did want to say that if anything could get me to read German, your web-site would be it! Beautiful work that I see there. I just wish I knew what the test and explanations were.

Keep up the superb work.

Take care.

Brian Laws>Hi!

Reply to
Brian Lawson

No problem.

Yes, i'm sorry. I can't find the time to translate it right now. But I will, promised!

this might help a bit:

Nick

Reply to
Nick Müller

What little I have recently learned about casting is that the core print is made from the sand mix stuff when the actual casting is done... the mold for the core print can be made from anything that is sufficiently stiff.

I dunno know what they do for lost wax process at all. This infor was/is what I gleaned for poured bronze or iron casting...

Everything I know could be wrong too... everything. :- )

_-_-bear

Reply to
BEAR

Silly thought from someone who has never done it - Have you considered lost-foam casting? As I understand it, you make an accurate model of exactly what you want in metal out of EPS foam, pack the inner cavities and channels with casting sand, pack the whole thing in casting sand, and then pour in the metal.

The foam pattern vaporizes as the molten metal runs in, allowing really complex shapes and cores instantly. That's how they do a lot of engine blocks nowadays, very detailed.

If you need it to look sand-cast, you can doctor the inside of the negative mold for the foam blanks to simulate whatever you want.

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Reply to
Bruce L. Bergman

And who's gonna make the foam prints? Me? You know, lost foam goes up in smoke. And so, I have _all_ the work again for a second piece. And there are quite a few duplicates (it's a

2-cylinder engine)*). Also, the pieces are _very_ fine. I doubt that I will get the necessary precision/finish. The scale will be about 1:15. No, that ain't an option at all! *) with all the forms, I can/could build a 1, 2, 3 and a 4 cylinder version. They all existed, and they only differed in the baseplates (3 different).

thanks for the idea, Nick

Reply to
Nick Müller

Greetings Nick, I learned, when doing lost wax, to make the cores out of the same investment used for casting the outside of the part. All the cores had access holes through the part of course. Anyway, the flask is fired to burn out the wax, then while still hot the metal is cast into the mold, then, after the metal has cooled a little the whole thing is submerged in water and the investment boils out. ERS

Reply to
Eric R Snow

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