I have my doubts about the ability of isocyanate curatives to cause any cross linking in household enamels.. gotta look into that one to be convinced. Don't add them to your 1/2a fuel because castor oil is a trifunctional (three hot spots per molecule) and will cross link and gel up.. It was used as a modifier in rocket propellant binder systems which are also isocyanate cured in many cases.