Pyramid Casting Mold 8948

Using Bullseye Mold Tips: Pyramid Casting Mold which offers the following firing schedule:

200dph.......................................1225 degrees........................hold 1 hour for frit, 2 hours for billet
600dph........................................1525 degrees.......................Hold 2 hours.  Instructions here are to visually inspect after 20 mins but I was unable to visually inspect for a number of reasons.
Full.............................................900 degrees..........................hold 1 hour
6 dph...........................................800 degrees..........................-0-
12 dph..........................................700 degrees..........................-0-
41 dph............................................70 degrees..........................-0-








So It came out okay, like the Bullseye tip sheet said "expect matte sides" and matte it was.  So looking around the internet I found a firing schedule for fire polishing the pyramid.  I am currently fire polishing it at the following schedule:

• Fire Polishing: Because this piece is thick we need to proceed with caution. Firing too rapidly will cause your piece to crack. It is better to err on the side of caution! Place your piece into the kiln on a prepared kiln shelf. Using the SC2, I fire at Speed 2 or 200 degrees per hour to 1365 and hold for 10 minutes, then lower the temp as fast as possible to 960 and hold for 4 hours to anneal, then allow the kiln to cool to room temperature as fast as possible. This will take several hours.

DO NOT PEEK. DO NOT CRASH COOL. DO NOT OPEN THE KILN UNTIL THE TEMP IS 200 DEGREES OR BELOW. BE PATIENT OR YOUR PIECE WILL CRACK.

I got this firing schedule from a U Got Glass in Frankfort, Maine project sheet for a hemispheric paper weight.  We will see how it comes out.  Other times I have fire polished a piece I have not noticed any real difference, but hopefully the pyramid will be more shiny.  Additionally I have prepared another filled pyramid mold.  This time in contrast to the first where I used mostly all fine frit, I used hand made clear frit which includes all the various categories of frit, fine, medium coarse, and extra coarse.  Within all that clear frit I placed two shades of opaque blue and one shade of transparent green squares.  I placed two layers of the squares lying horizontally and one layer standing up on the outer layer of the pyramid, these will be towards the bottom once fired.  It will be interesting to see if one can see through the clear frit, if the colored opaque that in lying horizontally can be see at all and if the transparent green that is standing up on the outer surface of the pyramid closer to the bottom can be seen better.    

What flattened this out?  Former pyramid shape is now a flattened square, with a slightly raised center nodule.   Not much.  What happened?  Is it because I held it a 900 degrees for  3 hours.  Because I dont think that 1365 degrees is too hot and the hold at 1365 was only for 10 minutes.  Yet perhaps 1365 degrees was too hot.  I found a list of temperatures that put fire polishing between 1300 and 1325 degrees.  So next time I will lower the temperature significantly.
So I will try again to make another pyramid

So I heated the pyramid to 1520 instead of 1525 because even 5 degrees is supposed to make a difference and tomorrow I will try to fire polish it even though the first time I did that it flattened out.  This time I will take it to 1300 and hold it at 900 degrees for 2 hours, I will follow the schedule:

200dph.................................1300 degrees........................hold 10 mins
Full.........................................900 degrees                        hold 2 hours
off

And it came out.  See....

The second picture is after firepolishing.