I just cut open an old inner tube I had laying around and noticed there is a white powder in there. What is it? Why is it there?


It is talc, and it is used in the tube making process to prevent the inner tube rubber from sticking to itself.

  • Thanks. Do you know how I can test if it's talc? Feb 9 '15 at 4:26
  • 2
    You'd have to do some chemistry, but I don't know the particular chemical tests you'd have to do off hand. You could email the tube manufacturer as well. Technically, I suppose it could be cornstarch as well, though talc is the traditional material.
    – Batman
    Feb 9 '15 at 14:13

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