Artist Residencies · Iceland: Kickstarter · Unclassified

Kickstarter update #24 is up!

Dear Backers,  Hope you have been enjoying your holiday celebrations {if you celebrate} and/or enjoying time away from the daily grind. Quiet time is always good! I want to thank you all again for your support. Items have been gradually shipping, making their way out to you since November 2015.   Some items take a bit of time due to preliminary concepts, sketches and the different materials being used. That said- I take my commitments seriously and thought this might be a good time to share some material process with you.

postcards shipped out to various locations 
postcards shipped out to various locations

The higher end Backer pieces take longer to complete/ship. None of these works are prefabricated, snap together objects. Each piece is entirely one of a kind, built from scratch -so to speak- and involve a high level of craftsmanship. A primary aspect, having to do with glass, is time in annealing cycles. The thicker the glass pieces, the longer they take (days, weeks) to anneal. Annealing is a process of slowly cooling hot glass to relieve internal stresses after it was formed (more on annealing below for those of you interested. Taken from Wiki).

The Elves, Valkyrie and Go∂ar (aka chieftain) Backer works have been carved and sculpted out of clay or wax or a combination of the two. These models are then worked together with clay firings I did while at Gullkistan, Iceland (for fit) and then moulded. The moulds are left to dry for a week or longer (depending on size/thickness) then the wax is steamed out (clay is often removed once the mould materials initially set-up) and I often alter the negative space, in the moulds a bit.

IMG_1527
WiP bronze, raku, crystal and lava from Hekla

The moulds are carefully brought up to 210f and sit at this temperature for 5-6 hours removing all water content.

Meanwhile, I’ve had to work around other scheduled studio events, classes and people working out of nanopod studio. When the annealing kilns aren’t available I have to wait, but this allows time for metal fabrication and casting other components that go with the ‘wearable’ aspect of the Elf {elves in this case 😉 } and Valkyrie works. The glass sculptures are cast.

Casting cycle goes something like this: 100-275/hr to 1450-1500f held at process temp for a minimum of 20 minutes but generally longer to enable the moulds to be ‘charged’. Charged meaning- adding more glass to the moulds if necessary. The kiln door is opened for a quick peek. Then giant Kevlar gloves are donned, along with a face shield and other protective clothing in order to carefully ladle glass into the moulds. Once the moulds are sufficiently filled they are again left to sit at process temperature then brought to annealing temperature and left there for hours/days- depending again on thickness. Annealing temperatures range from 820-900f. Once this cycle is completed the glass cools at 50-90f/hr to 500-700f. At this point the schedule shuts off (timers go off) and the glass sits in the kiln until it reaches room temp. This is a day or two.

Cold working! The glass is carefully removed from the plaster-silica moulds and cleaned. Gates/sprues are removed via diamond tile saw or ground off using diamond bits with a flex shaft machine aka foredom (aka dremel). Sandblasting might be necessary to help remove mould particles from air bubbles on the surface of the glass, and also used to carve out symbols in the glass with the use of masking materials (shown below).

 IMG_1616
Jötnar level pieces

All of the glass pieces are hand sanded using silicon carbide and wet-dry sandpaper, then fire polished. Clay components are then added and adhered to the glass. Where possible I have/am casting lava (from Hekla) in place.

 FullSizeRender
Bronze cast with lava from Hekla

If the glass works are not readily wearable due to weight and bulk I have then created a removable aspect that can be worn. Written instructions might even accompany your pieces! 🙂 or even a little demo video on how-to wear the wearable. The Elf(ves) and Valkyrie are shipping out soon (w/tracking & insurance) and I think I can safely say that the Elves and Valkyrie Backers can expect their gifts within the next several weeks (shipping included in this time estimate). The Jo∂ar [chieftain] is shipping a bit later (and I more than appreciate your patience and understanding, Charlie!) due to a massive shipment making its way into Canada to nanopod studio. This new equipment will enable me to (at last) go where I have been striving to land for years. No kidding- since 2010 I have been working towards owning this equipment. It is pricy and not available in Canada. Freight shipping over 300lbs ain’t small potatoes so, again time has been a factor.

Well, there it is! Thanks again for all of your patience. Please let me know when your items arrive. Items that were sent out over the holidays might take longer to reach you, but rest assured everything is on its way to you! xox Tosca

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Valkyrie sculpture WiP


*The annealing process may be carried out in a temperature-controlled kiln known as a lehr.[1] Glass which has not been annealed is liable to crack or shatter when subjected to a relatively small temperature change or mechanical shock. Annealing glass is critical to its durability. If glass is not annealed, it will retain many of the thermal stresses caused by quenching and significantly decrease the overall strength of the glass.

The glass is heated until the temperature reaches a stress-relief point, that is, the annealing temperature (also called annealing point) at a viscosity, η, of 1013 Poise (“Poise” is a measure of absolute viscosity; 1 poise = 1 dyne-second/cm²), at which condition the glass is still too hard to deform, but is soft enough for the stresses to relax. The piece is then allowed to heat-soak until its temperature is even throughout (this annealing temperature is usually in the range of 850–900 °F). The time necessary for this step varies depending on the type of glass and its maximum thickness. The glass is then slowly cooled at a predetermined rate until its temperature is below the strain point (η = 1014.5 Poise). Following this, the temperature can safely be dropped to room temperature at a rate limited by the heat capacity, thickness, thermal conductivity, and thermal expansion coefficient of the glass. After the annealing process the material can be cut to size, drilled or polished.

At the annealing point (η = 1013 Poise) stresses relax within several minutes, while at the strain point (η = 1014.5 Poise) stresses relax within several hours.[2] Stresses acquired during and remaining from temperatures above the strain point are permanent unless annealed and may lead to short-term or much delayed failures. Stresses acquired during cooling below the strain point are considered temporary, although they may be adequate to cause short-term failure.

  1.  E. F. Collins (1921) Electrically heated glass annealing lehr. Journal of the American Ceramic Society 4 (5), pp. 335–349
  2. Jump up ^ Werner Vogel: “Glass Chemistry”; Springer-Verlag Berlin and Heidelberg GmbH & Co. K; 2nd revised edition (November 1994), ISBN 3-540-57572-3

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