Getting epoxy glue off of aluminium is not easy. You sould not go beyond 210°C or so as aluminium will start recrystalising somewhere around there. But 210°C will only weaken, not destroy, the epoxy. So you will probably still need considerable force to remove the tube stubs. I would probably drill a radial hole in the stubs and atach some sort of lever to try and rotate the stub when its heated. Another approach would be to cut the stubs off with a rotary tool or similar. Good luck.
Getting epoxy glue off of aluminium is not easy. You sould not go beyond 210°C or so as aluminium will start recrystalising somewhere around there. But 210°C will only weaken, not destroy, the epoxy. So you will probably still need considerable force to remove the tube stubs. I would probably drill a radial hole in the stubs and atach some sort of lever to try and rotate the stub when its heated. Another approach would be to cut the stubs off with a rotary tool or similar. Good luck.