If you want to be safe I suggest to multiplicate wallet.dat file into many copies to fill the mass storage (m-disc) to the limit. Then even if say >90% (depends on the storage size and luck) is corrupted, it's still possible to recover data.

If you prefer to have one solid copy use this: http://www.youtube.com/watch?v=qpOV6r2vy9Y
though I don't know if the 'printer' stores anything in the memory.