Month: November 2019

After the success last year, we set aside a few weekends to build stained glass pieces for this year's Desert Bus for Hope (more extensive work-in-progress photos in the imgur gallery here). After much debate, we settled on designs based on our favorite pieces of art from War of the Spark, the Magic: The Gathering expansion released in May of this year. I chose Ugin, the Ineffable and Ouliana chose Liliana, Dreadhorde General - both using the alternative art that was available in Japanese language packs.  I should note for the interested, both these pieces were sold by auction earlier this month as part of Desert Bus 2019. Together they raised a combined $9,572 for the charity Child's Play!

Just like last year, the vast majority of the credit for actually planning and executing the pieces goes to my partner. Still, I was glad to help out a bit with cutting, grinding, and such. The pieces turned out amazingly well, but were both much more intense undertakings that the previous year's piece, with many more individual pieces of glass, in stranger shapes (possible thanks to our newly acquired diamond saw), as well as tons of hand-painted details.

One thing we hadn't considered when planning the pieces was how they would be shipped. For previous projects we'd used the fancy reinforced art boxes offered by FedEx, but learned that they'd recently been discontinued.  We were able to get one back-stocked one to use for Liliana, but Ugin was simply too large. This necessitated another side project: Building a crate fit for a spirit dragon! We settled on a rigid wooden outer case with a sandwich of styrofoam and egg-crate foam inside, isolated from the edges with bubble wrap. By necessity it had to come together in just a few days, and given that limitation it came out quite well!

Next year, if we keep up the tradition of building pieces for Desert Bus, we'll start from the available crate size and work our way backwards! 

After months of waiting, the class finally came! I attended the lost wax casting class at The Crucible, the excellent studio and teaching center in Oakland. Unfortunately I was just getting over a cold during the weekend the class happened, so I wasn't the most creative or adventurous with my projects. My target was to cast a ring with a functional stone setting in the correct size - admittedly none of this requires casting, the same result could be sawed, hammered, and soldered together without all the complexity of working with wax, planning sprues, etc. Still, sticking to a fairly simple goal meant I could spend time absorbing the new information and taking notes for when I'd like to replicate the process at home.

The first step was to carve, mold, saw, file, and otherwise shape our object using a variety of waxes. I stuck to a simple ring pre-form with a few wires added to serve as prongs to retain a stone. Once the wax object was complete, it had to have sprues added to it - these will become the "pipes" to deliver the liquid metal to the volume of the object! Once it's all assembled, we measure it's mass. Knowing the density of both wax and silver, as well as estimates for the additional mass of the "button" (dome at the bottom of the flask), we can calculate how much silver we'll need to fill the entire object, the sprues, and the button.

That done, using even more wax we built our sprue'd parts onto the bottom of a flask. Once secure, investment, a type of high-temperature micro-porous plaster, is poured around the form and allowed to set for several hours.

Next the flasks were placed into a kilt openings-down, and put through a burn-out cycle. The temperature slowly ramps up allowing the wax to melt out of the investment, and eventually gets hot enough to cause it to breakdown into CO2 completely. Doing this slowly prevents ash from clogging up your mold, as well as any explosion a more rapid heating could cause. Once the wax is gone and the flask is hot, it's ready for casting! If the flask is allowed to cool, the liquid metal can freeze the moment it touches it, ruining the casting. Before we cast though, we have to measure out our metal based on the calculation did earlier - they look a lot like nerds, just harder on the teeth.

Now we're ready to cast! The charge of silver is placed into the horizontal crucible, and the pre-heated flask is fitted into the holder behind it, and the centrifuge is turned a few times to build tension into the spring. As the metal is heated with an foxy-propane torch, borax flux, added with a carbon rode, is used to minimize dross and stir the melting silver. Once it's melted completely, the torch is removed the moment the centrifuge is unlocked, and the force of the spin forces the metal into all the detailed crevices of the mold! It's worth noting, the air being displaced by the metal is mostly pushed out through the porous investment rather than bubbling out the entryway.

The flask is then moved to a shelf for a minute or two until the silver of the button has cooled enough to no longer glow. Then the flask is submerged into water and agitated, hopefully breaking the silver free from the investment. If allowed to cool too much, it won't break free and will need to be chiseled out.

  The last thing to do is cut the piece free from the sprues and finish it like any other piece!

It turned out to be one of the uglier rings I'd ever seen, but only because my wax model was a particularly uninspiring lump. Still - I learned the process, and having significantly more than three hours to work on a max model in my future, I'm sure my next attempt will be a stunner!