'Web' on castinq

[fest]

as I work in a Casting House
I thought I would chime in here

the 'webs' on the Casting I believe are from Seams
left in the mold when it is assembled

that is, typically a mold is made from several smaller pieces
so that they are easier to make
and can be removed from the pattern more easily, etc

these pieces are then joined together
to make up the final configuration of the part

seams are left where the pieces are joined together
typically these are smoothed over-
but sometimes left on interior surfaces
where access is difficult
(or places where they won't show, in this case)

NOTE: I work in Investment Casting
(i.e. 'Lost Wax' process) NOT Sand Casting
but the techniques are very similar

AKB
a-Ferrari

[Tom Wilson]

Ok, so Investment means Lost. Sounds like the kind of investing I do!

Actually, this sounds really interesting. What do you do with this casting? What do you make? I picture sparks flying as the steel is poured into the mold. It sounds old fashioned and high tech at the same time. Can you make one off pieces or only large quantities?

[kare]

I would assume a brake drum mold be assembled of two halves, which makes me think that the web pattern may have been created by chills, which were used to cool the center of the mold to get the directional solidification to start in the center of the drum and run outwards. Directional solidification will eliminate porosity and distortion. Both strength and dimensional accuracy are important when making brake drums!

Lost wax is perfect for casting one-off near net shape items (no or very little machining needed) of any metal. I made my master's thesis on manufacturing one-off cast iron tools.

Best wishes, Kare

[Rudy van Daalen Wetters]

The lack of "directional solidification" was the basis for the dissolution of my first marriage.

I can relate to these brake drums very well, thank you.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

[tyang]

I would assume a brake drum mold be assembled of two halves, which makes me think that the web pattern may have been created by chills, which were used to cool the center of the mold to get the directional solidification to start in the center of the drum and run outwards. Directional solidification will eliminate porosity and distortion. Both strength and dimensional accuracy are important when making brake drums!

Not knowing anything about casting techniques, did the technique of "chills" exist in the 50s?

Tom

[fest]

'chills' as used in investment casting
are used in sections where the wax is too thick to solidify readily

I was not aware that chills could also be made of (the same) metal
and placed in the mold and then cast around
to allow more even solidification

very interesting

as for the use of chills in the 50's I do not know about that

the photos I have of the Ferrari foundry
do not show the use of chills
but as many aspects of Ferrari's Foundry were proprietary
this may be difficult to ascertain

AKB

aFerrari

[kare]

Those drums are alumium with an integrated steel liner, aren't they? I have a German book on foundry techniques. It includes most chill and feeder techinques and was first printed in 1933.

[tyang]

the photos I have of the Ferrari foundry
do not show the use of chills
but as many aspects of Ferrari's Foundry were proprietary
this may be difficult to ascertain

Unfortunately those trade secrets affect how much we know about Ferrari's history!

Those drums are alumium with an integrated steel liner, aren't they? I have a German book on foundry techniques. It includes most chill and feeder techinques and was first printed in 1933.

I guess the steel liner was cast in place? So if your drum is bad, you have to find another one!? Are these available anywhere? I wonder if Classique is going to remake those?

Tom

[kare]

Should be relatively easy parts to remake: find a suitable liner and make a wooden pattern, take it to a to a foundry shop and cast it. Too bad my car has disc brakes!