Question:

Do a google search on sand casting.  Special sand, and now there are binders that help the sand stay together.  Is fairly easy and reasonably cheap.  As low cost for molds, especially compared to die casting, which uses polished metal molds for better surface finish.  Most golf club heads are die cast. Bill

– Hide quoted text — Show quoted text – * the casting process for the water jacket manifolds is not complicated, but * it IS tedious and prone to occasional failure at the foundry, hence the high * price of a new manifold. * * First you start with a design. * Then you have a patternmaker make the patterns for the manifold and all the * cores to make the water jackets. What are the patterns made from? * Then you go to a foundry and have the molders ram up sand around the * pattern, place cores, and fill with molten metal. Using iron or aluminum, * the only difference is the melting point. Iron melts at about 2300 deg F, * Aluminum at about 1280 deg F. How do they make sand firm enough? And HOw do they take it out from the casting?? * After an appropriate amount of time (depending on the amount of metal used), * the sand mold is broken apart and the casting is cut free of risers, gating * and flash. interesting. igor * Then it goes to the machine shop to be surfaced and drilled in order to be * mounted on the engine. * * Are you sorry you asked about how it was made? * * — * * I have just removed my exhaust manifold and the gasket between it and * the engine looked pretty good. is replacing it a must? * * also, how are these manifolds made??? seems pretty complicated. * * igor * *

Response:

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* the casting process for the water jacket manifolds is not complicated, but * it IS tedious and prone to occasional failure at the foundry, hence the high * price of a new manifold. * * First you start with a design. * Then you have a patternmaker make the patterns for the manifold and all the * cores to make the water jackets. What are the patterns made from?

There are a number of materials used for patterns, depending upon the expected life of the casting program. Wood is cheapest, then wood and plastic, then a matchplate made of cast aluminum for long term (thousands upon thousands of castings) use. * Then you go to a foundry and have the molders ram up sand around the * pattern, place cores, and fill with molten metal. Using iron or aluminum, * the only difference is the melting point. Iron melts at about 2300 deg F, * Aluminum at about 1280 deg F. How do they make sand firm enough? And HOw do they take it out from the casting??

The sand binder basically is a paste made from wheat (although there are many many different types of binders available). After the casting has cooled, the sand is broken off the casting with hammers and the interior sand is shaken out with any number of vibratory gizmos wielded by foundry workers. – Hide quoted text — Show quoted text – * After an appropriate amount of time (depending on the amount of metal used), * the sand mold is broken apart and the casting is cut free of risers, gating * and flash. interesting. igor * Then it goes to the machine shop to be surfaced and drilled in order to be * mounted on the engine. * * Are you sorry you asked about how it was made? * * — * * I have just removed my exhaust manifold and the gasket between it and * the engine looked pretty good. is replacing it a must? * * also, how are these manifolds made??? seems pretty complicated. * * igor * *

Response:

I have just removed my exhaust manifold and the gasket between it and the engine looked pretty good. is replacing it a must?

You should never try to reuse a gasket.  It may look ok to the naked eye, but it has been severely compressed by the installation process, and probably will never mate properly again if you try to reinstall it.  Gaskets are cheap, and the risk of failure is high. JG

Response:

the casting process for the water jacket manifolds is not complicated, but it IS tedious and prone to occasional failure at the foundry, hence the high price of a new manifold. First you start with a design. Then you have a patternmaker make the patterns for the manifold and all the cores to make the water jackets. Then you go to a foundry and have the molders ram up sand around the pattern, place cores, and fill with molten metal. Using iron or aluminum, the only difference is the melting point. Iron melts at about 2300 deg F, Aluminum at about 1280 deg F. After an appropriate amount of time (depending on the amount of metal used), the sand mold is broken apart and the casting is cut free of risers, gating and flash. Then it goes to the machine shop to be surfaced and drilled in order to be mounted on the engine. Are you sorry you asked about how it was made? —

– Hide quoted text — Show quoted text – I have just removed my exhaust manifold and the gasket between it and the engine looked pretty good. is replacing it a must? also, how are these manifolds made??? seems pretty complicated. igor

Response: