I simmered a white-tail skull, slathered on some basic white/20 volume(didn't have 40) and set it out in the sun for a few hours. I usually set it in front of a heater, but mine was broken. So I ran to town to get a new one while the skull set in the sun, temp was cold about 35 degrees. When I got back I set the skull in front of the heater for about 25-30 min. When I went to check on it and turn it, the bridge of the nose had separated and had a bout a quarter inch gap, it was like the whole skull was going to split in half. I have never had this happen before...how can I prevent this? To fix the skull I super-glued and wrapped in tape until glue set....it sorta held. Thanks for the help.