Hello, I am new to the painting technique but I have given it a shot. I purchased all the paint, primer and hardner and thinner from Napa. I mixed the primer according to the specifications. 4:1 Spraying didn't go to bad but I put the gun down for a 5 minute break and the primer hardned in the gun. Is there something to break it up to get it working again or should I just buy a new paint gun? Any advice is appreciated.