Pewter Casting: Third Time's a Failure

(I have notes for the 2nd time we cast pewter but haven't posted them.)

This time what we wanted to do is to burn out the wax and melt the pewter at the same time, with everything all together in the kiln. Like that, the molds would be clean and at more or less the same temperature as the molten metal. It might result in a better casting, and would be more efficient energy- and time-wise, too.

But of course it wasn't.

First, we loaded up the kiln with our molds and the pewter in a crucible as well. But we needed something to catch the wax from the molds. So we used this aluminum food tray, figuring that since the temperature would be very low, it would be all right.

It wasn't.

Hole in tray

My dad joined us that day so we put him to work fashioning a new tray out of sheet metal.

That worked. With our pieces on little stilts, the wax dripped out fine, as you can see.

But somehow the pewter in the crucible didn't melt. There it is below the tray, nice and solid.

Not sure how we didn't reach melting temperature, but in the end we decided to just melt it directly. This is Jorge melting the pewter in a pot directly with the burner. Very directly.

Personally, one thing I wanted to try this time was a different design for the salamander mold. Instead of an open-face mold with the salamander lying horizontal, I tried a mold that would be cast vertically, with vents and connections between some of the limbs for better flow during the pour.

Here's the figure in the box, sitting in some plaster. I then poured more plaster over it to make a solid one-piece mold so the entry point would be where the tail is.

Salamander, head-down in the mold

I thought it might make for a cleaner casting, eliminating the need for this kind of cutting later.

Jorge doing some major finishing work on his salamander.

But it didn't. In fact, the mold split in two, right where I had poured the plaster in two rounds. (One lesson learned.) Hoping against hope, we tried to keep it together with some wire, and then we cast the metal.

Still life: Charred mold with wire.

That didn't work either (second lesson learned). In the end, my mold broke into about 5 pieces, and all that came out was a bit of leg.

Here's how it might have looked, had it all stayed together.

Now, Jorge's Venus came out with many little nodules.

We suppose it was the result of his plaster mix being too wet, so it was too porous when dry. When he mixed it, he added water to the plaster powder, but the instructions say one should add powder to the water. Was that the reason?

Mixing up and pouring the plaster.

Gloria's yoni-lingam was poured with the same mix, so we'll see how it turns out when she finally demolds it. Will it have nodules like Jorge's Venus? Looking at the mold we could definitely see air bubbles in it.

Sigrid's little Egyptian cat came out quite well (she used a different plaster mix than Jorge's), although there was a strange fault in the metal behind one ear.

Funny how in our first attempt, everything came out so well, so easily. But in our third, nearly everything went wrong. Of course, we were trying lots of new things, but in our first pewter casting we also tried something new.

In the work of the Crafts, many failures mean that we have the possibility of learning a lot.

And if that's really true, then at this rate, we'll be enormous Craft geniuses soon!