So I've been shoehorning in an hour here and an hour there between paying work to get my waxes in good shape for a day of casting. Then to my good fortune I had a full weekend at home and some paid castings to do for work as well.
Waxes, ah how I love them, so much potential, with such a humble materials. Modeling the details back into the copied waxes is really best done in a cool room which in the case of my basement is nooooo problem (concrete floors suck).
In this first picture, from left to right is the "master wax" and then the copies starting from
untouched, fresh out of the clay, to 100% finished up.
\Here are the finished waxes with little tapered sprue nubs for where the metal will be poured in.
And then there was grog.... Grog you say? This doesn't look like rot gut booze... It looks like smashed up earthen ware.... Why yes! It is :) and all this smashing fun in an effort to temper the clay to reduce the shrinkage rates and stress during drying and firing.
I sieved it because I could and also 'cuz too large particles will cause troubles.
You can actually see the colour difference in the two types of clay here. The grog-ed was added at 1/10th by weight of dry grog to workable clay. I used it for the crucibles and one each of the two types of models.
There were some drying issues, mostly along a seam on one brooch and at random along the middle of a belt end, the first is predictable and can be moderated by better blending seams. The second may be a result of not enough support when drying. The lip of the sprue collar stands out by about a cm leaving a long span unsupported in the middle when it was drying. I'll try drying it on its end and more slowly next time, perhaps 3-4 days in plastic as opposed to 2.
I did try patching the one break...
Clearly to no avail. One mold broke cleanly along it's seam and the other broke in two parts after being fired up to 1800'f . Really the molds didn't need to go up to nearly that high but I wanted the crucibles well fired and the molds were along for the ride.
\
After letting the kiln cool down over night I pulled everything out and wired the broken pieces together. In small batches I alloyed my bronze 4 parts Copper scraps to 1 part lead free pewter (from rio grande)
Till I had as much as would fit, 75 grams, this is also about the max that I can get liquid in any reasonable time with my wee jewellery torch set up.
Not knowing how the wiring would hold up, but game to try I heated up the kiln with all my molds in it to 250'f and let them soak up the heat for about a half hour. Then to test with pewter first...
A clean pour with some drippy-ness out of the cracks, but not too bad.
Then to brave the bronze in a slightly less broken mold.
And while that cools it's time to start chipping away to see if the first pewter one succeeded.
" Oh! How cute! Aloo' little wolfie... Please be all in one piece."
VICTORY! And ooooooohhhhh,shiny!
You can see where the break was there is some flashing and fins, but these are easily taken off with pliers and snips.
Next UP! Bronze, the batch alloying went much better so this mix had really good fluidity and it went into the mold without even a leak.
A few more pours later, while still bouncing with the joys of successful casting (failure would mean all the hours carving the waxes would be lost so I am a Happy Goldsmith) it was time to figure out how to crack these nuts. When to quench, and where to strike to get useful cracks and breaking was a bit of fun figuring out, but by the third one they were coming out with very little fuss,
I kept this one's clay front as a good sample/example for when we do demonstrations and talks with the SCA.
A fast, dirty and very period way to cut through metal.
A few months work made real in a day, never minding the time it will take to clean them up and install their pins. On a side note, though I didn't take any image of their undersides all of the pin hooks and hinges turned out and I made them in three thickeness' in case the reason the first ones didn't cast was that, and they all turned out exactly as carved. So I'm going to guess that the earlier trouble were caused by the slugishness of my first botched try at alloying bronze. .
What's Up Next... ?
Patience... I haven't a hope of casting these without a forge setup so I had best get to making and finding all the parts I need. In the mean time, I'm sure I'll find something to keep me busy.
Sincerely, Orla.
