I am mixing two-part primer (Interthane Epoxy Barrier-Kote) and I used a wax-coated measuring cup to measure and mix. Any chance that the wax will scrape off and interfere with the bond? Should I switch to a plastic cup next time? What made me think of this is that I went to the Unwanted Commercial Website, below, and saw that they have "uncoated" measuring cups on clearance, so I guess it must be important for some things. I just applied the first (very light) coat of the primer, and it went on stippled instead of smooth. I attributed that to a bad foam roller, but now I am having second thoughts. Thanks.