i just had a look at mine.the cup is in two parts with the
 base "glued" in with some sort of tan colored, epoxy??..i have
 had many hot drinks out of that cup but never put it over
  a campstove flame--however..the surplus canteen --the one with
  the cork stopper--has a cup stamped from one piece of aluminum
  and i have boiled water over a wood fire with no problem..i did
  that when i was looking for a container that i could cook in
  for my Ditch Vest PFD--