Shrinkage without definition

Hello,

I am casting earring hearts using a mold that has 16  3/4" x 1/2" deep heart shapes. I use ZYP/BN.

I use fine frit by BE Coe 90. I put the frit in and pack it well, then add more to make a raised area to get more frit into the mold.

I am using an Evenheat Pro 14 with TAP and SS relays. I use a program for casting 90coe as follows:

1) 500/400/10 2) 500/1000/10 3) 500/1200/5 4) 700/1500/60 5) AFAP/990/25 6) 600/940/45 7) 300/750/1

The hearts come out quite shrunken, more rounded than with the heart shape. I have even added more frit after the first firing and refired the pieces with only moderate success. I think the mold openings are just too shallow/small, but I can't find any 1" x 1/2" heart earring molds. Any suggestions???

Jen