Cast an inline 4 engine block with plaster mold

[Xijian Su]

Hallo to all!
Recently, I started my first project. I tried to cast aluminum alloys with plaster mold.

• Design the engine parts

This is the engine block designed with SOLIDWORKS. It takes me a week to build the 3D model.

• 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.

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

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

• Plaster mold making

The mixing ratio of water and plaster powder is 1:1.5.

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

 

[Xijian Su]

• Bake the mold

 

[Xijian Su]

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.

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

After a few minutes, I break the mold.

The casting has a fine surface.

 

[Rod Cole]

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

 

[retailer]

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

 

[aka9950202]

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]

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]

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

 

[mnay]

very good!!!

 

[gadabout]

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

 

[michelko]

Wow very nice.

Michael

 

[peter2uat]

@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.

 

[Brian Hutchings]

Thank you for posting your sequence for casting a cylinder block, very interesting and very informative.
Brian

 

[IceFyre13th]

What was the mold shrinkage % after curing and casting?

 

[kadora]

thank you Peter2

 

[Dubi]

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]

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

My engine drawing is referenced to a 15cc inline 4 model engine designed in 1940s which name is "seal".

 

[Xijian Su]

What was the mold shrinkage % after curing and casting?

About 3%

 

[Xijian Su]

@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

 

[Xijian Su]

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

15cc version