The poly you want is "Minwax Fastdry Polyurethane" not the wipe on stuff . As Christopher said , the wipe on is much too thin and would require many coats to build enough finish to use on pens . What most likely happened to your finish is you didn't give it enough time to cure . A thin coat takes from 24 to 48 hours to FULLY cure and thicker coats take much longer to cure .
With the Fastdry Poly you need to wait several days for it to fully cure before you sand and buff it . You can Post cure it with heat (125 degrees for about 2 to 3 hours) and then let it sit overnight before sanding and buffing but you should still wait about a week before using or selling the pen . It is not a fast finish for pens but once cured is is as good as CA .