Cast an inline 4 engine block with plaster mold

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Xijian Su

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Hallo to all!
Recently, I started my first project. I tried to cast aluminum alloys with plaster mold.
  • Design the engine parts
1UQ}T~TKBMHQ{F)S{%O[44F.png

This is the engine block designed with SOLIDWORKS. It takes me a week to build the 3D model.
IY~J2OGNHW9OTV3$7`7U207.png

  • Design the mold for 3D printing
To make the plaster mold, I've got to make a Silicone rubber mold first. So I designed a mold for the silicone rubber mold making. Here's the picture.
BZJJS]R}VQXD%]%R11N@BZN.png

Then I bought a can of silicone rubber from the "Taobao" for the mold making.
IMG_20200225_032604.jpg

There're 3 mold for the plaster core and mold making.
IMG_20200225_032736.jpg
IMG_20200225_032803.jpg

  • Plaster mold making
The mixing ratio of water and plaster powder is 1:1.5.
IMG_20200105_152336.jpg

This is the mold that hardened. The I put it into my electric furnace.
IMG_20200105_151722.jpg
 

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Xijian Su

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To prevent the plaster mold from cracking. I slowly raised the temperature. No faster than 150 'C / h.
Here's the curve of temperature I followed.
IMG_20200225_035830.jpg

After nearly a whole day later, the plaster mold finished. Then I poured the metal into the mold.
IMG_20200225_040136.jpg

After a few minutes, I break the mold.
IMG_20200225_040442.jpg

The casting has a fine surface.
IMG_20200201_002008.jpg

IMG_20200212_235824.jpg

IMG_20200210_214640.jpg

IMG_20200214_154549.jpg

IMG_20200214_154807.jpg

IMG_20200210_214917.jpg
 

Rod Cole

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Looks very good to me!!! Someday I'll use my brass-bronze scrap to cast something, I have enough for sure!!
 

retailer

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looks good - was the pattern 3D printed from the solidworks 3d plan
 

aka9950202

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WOW! What an amazing result. Are the plans for your engine your own design?

I will be watching with great interest.

Cheers,
Andrew in Melbourne
 

BillD

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Wow, I am surprised that heating the mould to that temperature worked. I would have expected the plaster of paris to revert to gypsum at about 100°C, and even more suprised that it sat at 730°C. But a very nice casting, Su.

Bill in Cardiff, Wales
 

kadora

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really excellent casting.
Two questions
1 did you pour liquid metal into hot mold ?
2 did you used common plaster or some kind of casting plaster.
Thank you
 

gadabout

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The design appears to be of the Westbury Seal. Is it the 15cc version or the 30 cc version?
 

peter2uat

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@BillD
according to
https://en.wikipedia.org/wiki/Plaster_mold_casting
you can use special plaster molds up to 1200°C / 2200°F - Xijaan Su even gave the heating/timing curves for drying the mold AND using it immediately thereafter in post #3.
Aluminum can be cast safely with this plasters, as can be brass - the temperatures here are 900 to 940 °C / 1,650 to 1,720 °F.
Always use a well dried & preheated mold to avoid cracking.
 

kadora

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thank you Peter2
 

Dubi

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To prevent the plaster mold from cracking. I slowly raised the temperature. No faster than 150 'C / h.
Here's the curve of temperature I followed.
View attachment 113992
After nearly a whole day later, the plaster mold finished. Then I poured the metal into the mold.
View attachment 113993
After a few minutes, I break the mold.
View attachment 113994
The casting has a fine surface.
View attachment 113995
View attachment 113996
View attachment 113997
View attachment 113998
View attachment 113999
View attachment 114000
Very impressive, well done.
 

Xijian Su

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@BillD
according to
https://en.wikipedia.org/wiki/Plaster_mold_casting
you can use special plaster molds up to 1200°C / 2200°F - Xijaan Su even gave the heating/timing curves for drying the mold AND using it immediately thereafter in post #3.
Aluminum can be cast safely with this plasters, as can be brass - the temperatures here are 900 to 940 °C / 1,650 to 1,720 °F.
Always use a well dried & preheated mold to avoid cracking.
Thank you!

Xijian Su
 
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