You just need to use the hotter water and then of course as it cools off the silica also gets firmer as well. User hot water my increaer the diameter of the silica as well but as the water cooler off the the silica should decrease in diameter as well.
Hot water grow faster but i would prefer yall use cold cause it hurts more but if yall dont want to hurt people i prefer hot cause it grow faster but either way hot and and cold hurt