Q: I have been using a wipe-on polyurethane finishing technique by mixing oil-based satin polyurethane with mineral spirits. It has worked well, especially while turning projects on a lathe. Am I missing something by not using the already prepared product such as Wipe-On Poly? Is there some additive missing from my procedure that will ease the application or enhance the finish?
A: Yes and no. Yes, wipe-on polyurethanes often have extra oil or some other ingredient that adds lubricity to the mix, making it easier to wipe and slower to dry. No, the addition of such ingredients does not enhance the final finish. In other words, if you are happy with how your homemade mixture of diluted polyurethane applies, there is absolutely no reason to switch to anything else.