18 Cylinders Isotta Fraschini (straight six-cylinder x3 )

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ajoeiam

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My garden foundry is open, the first brass casting
To support the shaft that drives the propeller I designed a cone for the ball bearings.
I made the mould with the 3D printer , I made the internal core with sand, sodium silicate and Co2





The core


still hot molten brass
View attachment 140318

View attachment 140319


Neato!!!

Next we get to see this cone in its final (read machined) state - - - yes?

Like very much!!!!!!!!
 

Foketry

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The finished brass cone
IMG_3674.JPG

IMG_3676.JPG

IMG_3675 (1).JPG
 

ddmckee54

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Foketry:

A couple of questions about your latest casting:
1) Did you use the same 3D print to make both the core print and the sand mold?
2) What layer thickness did you print this at?

Don
 

Foketry

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Foketry:

A couple of questions about your latest casting:
1) Did you use the same 3D print to make both the core print and the sand mold?
2) What layer thickness did you print this at?

Don
Yes , I used the inside of the 3D printed mold to make the sand core and the outside to make the footprint in the petrobond sand, this was possible because the angle of the internal cone is large , it was not even necessary to paint the mold

The layer thickness was 0.16 mm
 

ddmckee54

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Foketry:

In Post #120, in your picture labeled "the core", the sodium silicate core and the 3D printed pattern appear to be the same height. If they were the same height, how did you keep the core centered in the mold?

Don
 

Foketry

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Foketry:

In Post #120, in your picture labeled "the core", the sodium silicate core and the 3D printed pattern appear to be the same height. If they were the same height, how did you keep the core centered in the mold?

Don
It is not seen in the photo but under the core, during the hardening with CO2 I put 3 self-tapping screws.
Through these 3 screws protruding for half of their length ,I fixed the core to the petrobond inside the alluminium cope
 

ddmckee54

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It is not seen in the photo but under the core, during the hardening with CO2 I put 3 self-tapping screws.
Through these 3 screws protruding for half of their length ,I fixed the core to the petrobond inside the alluminium cope
Neat idea, I'll have to remember that one.

Don
 

Foketry

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I increased the models by 1.3% because of the shrinkage of the aluminum , using PLA
The additional orange parts are the channels for letting out the molten PLA and for pouring the aluminum into the plaster, once all the PLA has evaporated or burned. Of course the models are almost empty inside, there is only the outer skin

IMG-3455.jpg
IMG-3457.jpg
IMG-3458.jpg
 

Foketry

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I coated the 2 PLA models with several layers of ceramic
I use the ceramic powder, water and with a brush I deposit the ceramic on the model to form a layer of 5-10 mm. This requires at least 4-6 layers, allowing the ceramic to dry and harden for each layer before depositing the next layer.

gesso.jpg


I then cover everything with a thick layer of plaster mixed with sand, leaving the sprues uncovered

IMG_3653 (1).JPG

IMG_3654 (1).JPG
 

michelko

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very informative and outstanding work.. as usual.

Greetings Michael
 

ddmckee54

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What is the ceramic powder that you use to for the initial ceramic shell?

Waiting to see what the next step will be. You've either got a VERY steady hand while pouring or you are going to add some sort of pouring basin to make it easier too hit those sprues.
 

Foketry

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What is the ceramic powder that you use to for the initial ceramic shell?

Waiting to see what the next step will be. You've either got a VERY steady hand while pouring or you are going to add some sort of pouring basin to make it easier too hit those sprues.

I have tried both of these powders. The second seems to me to be more resistant to high temperatures, 500 C, with fewer cracks, but for a correct comparison it would be necessary to try both on the same piece with the same temperatures,and v with the same thicknesses .The second is also difficult to detach from the aluminum casting, the first "sticks less" to the piece.
It is not very difficult to center the pouring hole, being plaster I can place the crucible on the edge of the plaster block and then pour, o course I put the plaster block in a container full of sand, if the liquid aluminum comes out, it remains contained in the sand and my feet do not cook like a roast chicken :p

I have tried many times not to use ceramic but only plaster, special plaster for foundry but never got good results, only and always crack , maybe my 500 degree C heating process is incorrect.
 
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Foketry

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If I may add to what @ddmckee54 is asking, you said you did several coats waiting for each to dry. Could you estimate the time to dry? That is more like one hour to two or more like 12 hours or more?
the ceramic powder solidifies in 20-30 minutes generating heat , after which you can make another layer, it does not need to be perfectly dry, rather it is better that it remains wet, the layers stick better to each other.
 
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