the hold out with some of the k200s was good for me sure there is better. most of the time there is. as epoxides can be cross linked to poly urethanes Aliphatic s epoxy what i used to paint my machines in the shop and cross link to many other make ups . i have had many job s i done with the k200s but i seen it in the wrong hands in production shops try to hind a 40 grit mark i will shink up . most all the time i never tried to fill up poor work when another coat of fill would do the job. many times i would let the sun bake the primer with it cut open . i have to watch out for some epoxy the dust i have a lung/ skin sensitive from it