Tuesday, August 5, 2014

Catching Up Part 5: Spruing

The World English Dictionary states that "Sprue" means:

n
1. a vertical channel in a mould through which plastic or molten metal is introduced or out of which it flows when the mould is filled.

Also of interest, there is an alternate meaning of which I had no idea:


n
a chronic disease, esp of tropical climates, characterized by flatulence, diarrhoea, frothy foul-smelling stools, and emaciation.


Having spent a lot of time in various Spruing Departments I can safely say that both definitions are spot on.

All sprued up and ready for shell.
 

In the photo above, the head has been inverted and the crown of her headdress removed. The circle on the bottom is pure wax as are the various 1" bars that are attached to her. These bars will provide both a way for the molten bronze to enter the ceramic shell and also a way for the gasses to escape once they are melted out. If this doesn't make much sense yet, hang on, all will be explained. I hope.

Need a hand?
 

Wax cross bars have been added to the base.

Jason starts on the torso.

Prepping the urn.

Note the "plug" taken out of the top of her hand.

All of the wax bars are "welded" in place with a soldering iron, fusing both waxes for a bond that will hold up to the rigors of the Shell Department. If you notice in some of the photos that there are pieces missing (see the hand above for an example), these are called "plugs" and they are removed so that the ceramic shell can dry more quickly before they are melted out and the bronze is poured. All of the plugs are sprued and cast separately, to be welded back into place during the final bronze fit up.

All in all, I believe the Spruing Department at Madd had four people working on her for a little over a week to meet my deadline. A big thanks to Tiffany, Gayle, Derrick, Jason and their tireless leader Bonnie for doing such an excellent job. You guys rock.

In my next update, I actually got to take a few days off and have the photos to prove it. Stay tuned!

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