✔ 最佳答案
I did it last week and was fine - I painted wine glasses and jam jars as Xmas gifts then put in a non-preheated oven for 30mins at 170degrees celsius. All worked well and no cracks, explosions or anything. Just make sure you leave the glasses to cool down in the oven afterwards and only remove when they're cold. I think exploding glass tends to happen when the temperature of the glass changes very quickly.