Thanks guys, I hadn't thought much about the hardner, I thought the filler itself might be getting old though. I've tried two different tubes of hardner and used alittle hardner and alot of hardner, it doesn't seem to matter about that. The filler always drys, it doesn't stay gummy, just sticky on top as described. Most of my filler is less than 1/8th thick so I've just been using a sanding block to start, I'll try using a rasp and the other ideas ya'll mentioned and see if it helps.
Thanks again. Scott
