Saturday, February 05, 2011

digital mills and press-forms

Continuing with the "Beneath the Skin" work, all that messing around with the digital scanner and the Polymer Clay models was to give me a press-forming die, of which I now have two, one with the heart at 25mm and 5.6mm deep...
The negative image into which the metal will be pressed.

Seen from behind, the positive image.

...and a larger one with the heart at 35mm long and about 8.3mm deep.
 These were tested out and formed little copper versions of the hearts, exactly as planned:

The copper here - small heart - is 0.4mm thick. The larger heart needs to be pressed from 0.6mm thick or it splits due to the depth of the press:

This project is all about using traditional Japanese alloys and colourings to create pieces and one of the features of the original heart drawing (shown in the previous post) is that it has very prominent black bands defining the chambers of the heart. I am planning to do this by using silver applied to the copper before it is pressed. This, obviously, gives problems of metal thickness and lining up the applied metal to the mould. In order to do this, I used locating pins on the moulds to allow the applied sheets to be lined up correctly:

The silver fused to the surface of the copper. I decided not to solder it as the solder was too visible at the edges of the silver elements.

Using a guide to drill the holes to ensure that the pattern lines up.

The location pins in the mould.

As the dies are relatively deep, they were pressed very gradually, with frequent annealing: the larger heart took 6 anneal-press cycles to attain the full depth of the die.

After the initial few presses.

The finished hearts, waiting to be cut out, coloured and used in the pieces.