Thanks guys, here's what I went with:
private static String makeStr(int num) {
int r,s=0;
r = ('a' + num / 26);
s = ('a' + num % 26);
String s1 = new Character((char)r).toString();
String s2 = new Character((char)s).toString();
return s1+s2;
} I appreciate the help - this is way simpler than what I had written.