re melt cracked piece

[Michael Stevens]

I had a 6mm panel shatter so I lined up the pieces up and put a little frit around the areas that cracked and re melted to. full fuse hold 15 minutes. one thing is crack line is visible, the other thing is after take out of kiln the piece made some slight sound like cracking but there aren't any cracks when observed with polarized light.

should I hold the piece at full. fuse longer, and should I anneal it longer?

[Sharol]

If you post your firing schedule and perhaps a photo, it would help in getting you some advice.