Started out making River Rock part sheet (PS). It turned out good. Made another part sheet using tekta with 2mm stringers in following colors: 0100, 0116, 0126 & 0009. Those came out good too.
Firing schedule used for making plates from part sheet pieces
400F 1225F 1:30
600 1490F :10
AFAP 900F 1:00
150F 700F :0
Fired plates to schedule above and had issues with all three. Hazing or cloudy through all the part sheets.
Have watched the 3 different subscription videos on making part sheets and plates. Also have watched video an understand the bubble squeeze.
The one video states that part sheets are prone to devit on the side that rests against the shelf. I sandblasted the shelf side with 220 AO sand, scrubbed and cleaned with both soap and water then alcohol like we do everything that I sandblast. Here is where where maybe the issue lies. The bumpy side or non shelf side was faced down and the shelf side (having been sandblasted) was placed face up between the capped Tekta.
Glass used for plates.
#1: 1164 border around river rock PS. Capped w/ 1100 Tekta. 8" x 8"
#2: 0100, 0321 around river rock PS. Capped w/ 1100 Tekta 10" x 10"
#3: 0100, 0104 around PS made with stringers. Capped w/ 1100 Tekta 16" x 4-1/2"
#1 Cloudy window through all part sheet. Champagne bubbles on border. This one is really not bad other than one bubble that is a little large. The cloudy part sheet looks pretty good with the blue transparent border.
#2 Had some clear window thru PS but majority was cloudy. Splotchy.
#3 Stringer PS is very cloudy and there are bubbles that almost appear to have small cracks radiating out from them. Majority of the larger bubbles are on top of the black 0100 stringer. Not sure why that is?
I thought the bubble squeeze at 1225 for 1:30 would have been enough but evidently not. Maybe on plate this big should shoot for 2 hours. As for the hazy areas, maybe I shouldn't have sandblasted them and had that part capped with Tekta?
Any help our suggestions would be greatly appreciated. Not sure if they are repairable at this point.