The trick to ptex is to keep the candle low to the board and to keep it from producing an orange flame. If you can do that, the ptex won't be as brittle and when you drag the candle along it fills in much better. If you can do that then it will hold in those scrapes. Once you flush up the p tex, wax your board a few times and your good to go. Get a drywall cheese grater to scrape down the ptex. It works better than a blade.
Last edited by ridinbend; 04-07-2014 at 05:39 PM.