$ gpg --export-secret-keys --armor > ~/private.key
$ ./qrencode -o test.png < ~/private.key
Failed to encode the input data: Numerical result out of range
How can I make that happen? Are there alternative programs to qrencode which can handle a very big GPG key? I want to print it on paper as this security.SE question suggested.
The comments of @geruetzel and @ cuonglm are addressing this version of my question.