Hello,
I'm a first timer with epoxy and I was really careful on the dosage and how long I would mix the resin, I also never mixed more than 300ml at the time.
Now it has cured for around 15 hours but it still feels gummy and it deformed easily if pressed.
For some reason I thought that 15 hours would already provide a hard surface, am I wrong?
I hope so as otherwise could be something much worst  : (
I try to keep the room temperature around 24 degrees it might have gone down a bit during the night

Any idea what could it be?

Full of hope looking forward to any help

Davide

Epoxy usually reacts much slower than polyester (if you are used to that). Most epoxys could be still gummi after 15h at room temperature and below. This is nothing to worry about. If it's still not cured after 48h, than you should start checking for mixing mistakes.