Wissmach 96 is made for glass fusing and kiln forming. Special care is taken to avoid devitrification and all our glass is tested to fire with any other glass that is labeled COE 96.
Frequently Asked Questions
What's the difference in kiln forming with "90" and "96"?
Really very little. What you learn with one glass will largely apply to the other. COE 96 is a lower temperature glass Ã¢â‚¬" that is, it takes less time / heat for COE 96 products to reach a given viscosity than it does common COE 90 products. Understanding this, and looking over the COE 96 Firing Guidelines, a kiln crafter will quickly adapt to the differences.
Should I test?
Testing is your best teacher. You'll discover subtle nuances in different glasses, monitor color shifts, and be better able to predict various characteristics that may result from the fusing process. Plus, because our equipment and procedures differ from yours, you just might uncover a set of circumstances in which our "Tested Compatible" glasses don't act as expected in your system of variables. Better to discover that in testing than in a disappointing project.
Are projects made with COE 96 glass "dishwasher safe"?
COE 96 glasses were not designed to stand up to the stresses of modern dishwashers. However, we know people (reliable sources) who swear they've been eating pancakes off fused Spectrum dinnerware (capped with 100sfs) and running it through the dishwasher for years, with no signs of weathering. This doesn't surprise us, as ours is a very durable glass. But we can't recommend selling your COE 96 products as "dishwasher safe." Better safe than sorry: "Hand washing recommended."
How can I prevent bubbles from forming between the kiln shelf and the bottom layer of glass?
This problem is gas. Small amounts of moisture in the kiln shelf or shelf primer may be turning to steam at high temperatures. Or, some organic material (dirt, filings or other debris) are burning and gassing off at fusing temperatures. The best way to prevent these types of bubbles is to use PAPYROS® Kiln Shelf Paper between the shelf and the glass. The paper is air-permeable and will allow more air to escape than in direct-shelf contact.
If you want to keep using shelf primer, try increasing the time spent around 250°F (hold it there for, say, 1/2 hour). By this point, the moisture has turned to vapor. Holding the temperature there for a brief period will allow time for the vapor to find its natural avenue of escape.
If you still have a problem, there is probably some chemical reaction taking place between the kiln shelf and the shelf primer. The reaction, which will be occurring at higher temperatures (1100 Ã¢â‚¬" 1300°F) is giving off a gas, which is creating the offending bubble. Solution? Again, first try taking it slower between 1100 and 1300°F. Spend an hour making that ramp. If that doesn't work, then try
a. a different shelf primer
b. a new batch of your existing shelf primer
c. a new kiln shelf, preferably made of a different material
Should I be concerned about gasses or fumes coming off your glass while I'm fusing it in the kiln?
When COE 96 products are originally made, the raw materials are melted at temperatures that are around 1000 degrees higher than normal fuse temperatures. Any volatile components in the raw materials are driven off and captured in our baghouse filtration during this process. Therefore, there are no volatile gasses or particulate matters left to escape from the glass during the course of fusing.