this ended up working for me:
gpg -a --export-secret-keys > exportedKeyFilename.asc
you can name keyfilename.asc by any name as long as you keep on the .asc extension.
this command copies all secret-keys on a user's computer to keyfilename.asc in the working directory of where the command was called.
To Export just 1 specific secret key instead of all of them:
gpg -a --export-secret-keys keyIDNumber > exportedKeyFilename.asc
keyIDNumber is the number of the key id for the desired key you are trying to export.