Blog update!! Investment casting

[Jim Kibler]

Hey there everyone.  There's another update to my blog that my girlfriend, Katherine, put together.  This briefly talks about some investment casting we've done and links to a very details "Instructable" she put together on the subject.  Here is a photo of one of the items we've cast.  Any questions or comments are always welcome.  http://www.jimkibler.net/blog/



Thanks!
Jim

[Scott Bumpus]

Neat Stuff. thanks for the info.  What kind of vacuum chamber is that?  Homemade?

[Jim Kibler]

It's basically just a big piece of PVC pipe with gasket material and clear acrylic to seal up the top and bottom.  It also has a guage to measure vacuum and a pet cock to release the vacuum.  Very simple.  I bought this from a company called Art Molds.  I wasn't experience when I purchased this, but now I would just make something myself.  Any more specific questions, just ask.

Jim

[Scott Bumpus]

Thank you.  Bell jars are EXSPENSIVE  I have been looking for something like this.
I already have a vac pump 7cfm.  Off to home depot   

[jerrywh]

I Think the vacuum chambers work better if you make them from clear plastic pipe because then you can see when the mold material collapses and also see if it begins to over flow the container.  Then you can control the process by varying the vacuum so the containers don't overflow.  If you do your own casting you can also use the vacuum flask for vacuuming the plaster flasks.  I also have a 5 gallon vacuum flask made from a large piece of metal pipe with a clear plastic lid. You can make the gaskets for the flasks  from the polyurethane mold material. you are only limited by your imagination.     

[Jim Kibler]

I'm with you Jerry.  The clear lid I have on mine lets me see things clearly.  It's no fun to clean up a mess from an overflow.

[JTR]

Thanks for posting the process on your blog!
I've never done it and only read about the process, but somehow I was under the impression the vacuum chamber was used to create a vacuum to help fill or inject the molten silver into the mold.
Now it sounds like maybe not?
John 

[Jim Kibler]

Yes, vacuum is used during the pouring process as well.  If you go to
http://www.instructables.com/id/Lost-Wax-Investment-Casting-of-Silver-Pendant/
the process is detailed.  This is an "Instructable" that Katherine put together.
To summarize the process, a vacuum is pulled at the bottom of the flask which sucks air from the mold, through the porous investment material.  This allows the ambient atmospheric pressure to in effect push the molten metal in the mold.  Hope this helps.

Jim

[JTR]

Okay, thanks Jim. That clears it up for me.
John

[Mick C]

This is very interesting.   And I love the example posted here.  The faces within the piece are awesome.  Thanks for sharing your process, Jim....Mick C