A while ago Bob Leatherbarrow gave a presentation to Lunch With A Glass Artist (LAWAGA) on slumping schedules. You can follow a recording of the Zoom meeting after joining the facebook group Lunch With A Glass Artist – Larry Pile.
The most important point for thinking about the process he follows is the order of slumping factors. They are:
span
thickness
viscosity
How big is the unsupported part of the glass? Glass on larger span moulds will begin slumping at lower temperatures than on smaller spans.
The thickness has an effect. With the same ramp rate thicker glass will need higher temperature or longer time.
The viscosity of the glass also affects the temperature of the slump. Low viscosity glass will slump at lower temperatures than higher ones, e.g., black vs. white.
Then you can begin to think about temperature and time. The objective is to use the lowest temperature to get the slump done in 30 minutes to avoid marking of the glass touching the mould, leaving a smooth shiny back.
There is a lot more in the presentation to LAWAGA. Join the facebook page to get access.
There is even more information about fusing principles and practices in his book Firing Schedules for Kilnforming, Just Another Day at the Office.
https://www.leatherbarrowglass.com/purchase/firing-schedules-for-kilnformed-glass
This inexpensive eBook is worth much more than the purchase price!
No comments:
Post a Comment