I have found that when I thaw and use frozen IMBC it weeps badly, I freeze it in ziplock bags which double as piping bags.
Any suggestions ?
Could it be that I am not using enough butter ?
You need to let it thaw in the refrigerator and then let it come to room temp. After that, you may need to put it in the mixer again because it has separated. After a few spins, it will come together.
I don't freeze, but I refrigerate it daily. I always give it a spin if I see any separation when I stir it.