i made a big mistake after a long night of painting and when i cleaned my spay gun i used hardener instead of reducer. Yeah, i was tired. so gun was a no go after that. But i found replacement parts and rebuild kit from TCP for it and thought i would give it a try. After complete disassemble, letting gun sit in parts cleaner for a few day and lots of time cleaning, i put it back together and it works great, just like new.