slumped edges

[Marie Lockburner]

I am new here & new to fusing glass about 1 year. With trail & error I want to succeed ! I have a Jen/Ken AF3P Bead Annealer about 11 by 9 octagonal in shape with a 4 inch flip door. My edges on fused pieces are very uneven some with spikes. My main question is why does the glass slump down to far into a soap mold generally on the long edge ? My settings are...ra 1 300 to 1000 degrees holding for 0, ra 2 500 to 1280 holding for 20 minutes & ra 3 highest temp then down to 950 holding for 27 minutes. ( it was 30 minutes and it was recommended to me to lower it a few minutes to maybe eliminate the spikes) it has lessened them only ;-( Any advice would be awesome

[Brad Walker]

The length of your annealing hold at 950 has NOTHING to do with the spikes. The spikes are caused by firing too hot or holding for too long.

The spikes (I call them needles) are more likely if you have a single layer of glass (instead of two) or if your mold has a really sharp drop (this could be the reason for what's happening on the long edge, but I'd need a photo of the mold to know for sure). In either case, firing to a lower top temperature and holding longer if necessary is the solution. But your annealing time isn't related to the needling at all.

[Marie Lockburner]

I am unable to get pics on here ;-( My piece of glass is the same size as the top of each soap dish. I did try the first time to make it 1/4 bigger on all 4 sides, but that extra basically slumped over the side but only on the corners. All the glass I have used in my molds has been 96 fusible of either Wissmach or Spectrum brands.

[Buttercup]

Marie, below the area where you post your message you'll see Options and Attachments. Click on attachments.

and follow the instructions. Jen (Sorry, I can't make the image larger.)

[JestersBaubles]

Your slump temp is too hot (at least if it were being fired in my kiln). I typically slump no higher than 1225. My normal schedule is a long hold (30 to 45 minutes) at 1100, and then a short hold at 1225. Often, by the time the kiln reaches 1225, the slump is finished.

Dana

[Marie Lockburner]

soap mold issue ;=(

[Marie Lockburner]

SO I am going to change some of my numbers with these NEW numbers.....please everyone comments please..........
ra 1 300 to 1000 degrees, hold for 0, then ra 2 500 to 1225 degrees & hold 30 minutes ( as suggested by JesterBaubles) should that hold time be longer ? than ra 3 highest temp ( 9999) than down to 950 & hold for my original 27 minutes. The ra 2 is the ONLY 1 I changed.
Also will all fusible glass use these same settings ?

[JestersBaubles]

I think you mis-read my original comment:

My normal schedule is >>>>a long hold (30 to 45 minutes) at 1100<<<<, and then a short hold at 1225. Often, by the time the kiln reaches 1225, the slump is finished.

I would not hold at 1225 for 30 minutes unless I was trying to slump into a deep mold.

The best way to determine how long you need to hold at your top slumping temp is to LOOK INTO THE KILN. The only way you will truly know what is going on with the glass is through observation. With experience, you'll get a good idea, but until you get your firing schedules nailed, I would recommend being present for when the kiln hits slumping temps and make note of what is going on.

Dana