glass won't slump/drape after pot melt
Posted: Tue May 12, 2015 11:50 am
I’m new to glass fusing and slumping, but thus far I’ve been pleased with my results. I’ve experienced a strange problem with my current project, however, and I can’t seem to find any information about what I might be doing wrong.
In short, I took a cobalt blue wine bottle, crushed it, then placed it in a stainless steel pot with a hole drilled in the bottom to run it through a pot melt cycle. The idea was to take the resulting flat melt and use it for slumping or draping in to a bowl shape. The pot melt went flawlessly and the result was an approximately 7” diameter disc of approximately 6 mm in thickness. For the next step I elected to drape it over an overturned stainless steel bowl. I ran it through a slumping/draping schedule that included a maximum temperature of 1200F for 20 minutes. At the end of the schedule, the glass hadn’t budged a bit. Figuring I wasn’t using an appropriate firing schedule, I ran another one up to 1350F for 60 minutes. Again, not a bit of change. Determined not to be defeated, I decided to run my initial pot melt program again (figuring I could start manually ramping it down once I noticed it start to slump). I checked after 60 minutes at 1700F and was astonished to find that once again the glass hadn’t moved. I manually ramped it up to 1800F and held for another 60 minutes and think I noticed the tiniest of droop around the edges of the disc, but after such a long period of time I started to worry about damaging my kiln so I shut it down and gave up.
I’m using a new Kingpin 88 kiln and it’s worked flawlessly outside of the present project. I’m not certain if the result of my pot melt is simply too thick to drape or slump or if the pot melt process changed something about the glass properties that’s rendered it unsuitable for slumping. In any case, I’ve looked all over and I can’t seem to find others who have experienced this problem. Any ideas from the group?
In short, I took a cobalt blue wine bottle, crushed it, then placed it in a stainless steel pot with a hole drilled in the bottom to run it through a pot melt cycle. The idea was to take the resulting flat melt and use it for slumping or draping in to a bowl shape. The pot melt went flawlessly and the result was an approximately 7” diameter disc of approximately 6 mm in thickness. For the next step I elected to drape it over an overturned stainless steel bowl. I ran it through a slumping/draping schedule that included a maximum temperature of 1200F for 20 minutes. At the end of the schedule, the glass hadn’t budged a bit. Figuring I wasn’t using an appropriate firing schedule, I ran another one up to 1350F for 60 minutes. Again, not a bit of change. Determined not to be defeated, I decided to run my initial pot melt program again (figuring I could start manually ramping it down once I noticed it start to slump). I checked after 60 minutes at 1700F and was astonished to find that once again the glass hadn’t moved. I manually ramped it up to 1800F and held for another 60 minutes and think I noticed the tiniest of droop around the edges of the disc, but after such a long period of time I started to worry about damaging my kiln so I shut it down and gave up.
I’m using a new Kingpin 88 kiln and it’s worked flawlessly outside of the present project. I’m not certain if the result of my pot melt is simply too thick to drape or slump or if the pot melt process changed something about the glass properties that’s rendered it unsuitable for slumping. In any case, I’ve looked all over and I can’t seem to find others who have experienced this problem. Any ideas from the group?