hmm, wrap your hopper....
first off you would have to wrap your hopper, and the paintballs in storage too because it defeats the purpose of wrapping up your hopper if the balls are already frozen.
just grab clothes and drape them over the hopper, then bind it with string, small rope, bungee cords, what ever.
do the same for your paintballs.
if you really want to get technical, go to some place like wal-mart, and ask for a foil blanket. these blankets are made of layers of foil, plastic, and other materials im not sure of, and are made to keep you warm in really cold weather incase of an accident. cut it up and use that to tie to your hopper. that would keep the hopper a good 10-15 degrees warmer.
heres a pic of what i mean
