I agree with monkeyboy, don't thin it if you can do it another way. I've seen to many people try thinners then complain about slow cure, no cure or sticky results. If you must use alchohol, don't use rubbing alchohol (all rubbing alchohol has a large water content), use denatured alchohol available in the paint section of most hardware or paint stores. Mild heat (less than 200 degrees) does not weaken it and certainly makes it very flowable and does decrease cure time. If you have a choice, use heat.