I am at the point where I am priming my latest project. Yesterday I covered it with 1/2 gallon of Feather Fill primer that I had on hand (about 2 years old) It was still slightly tacky and was impossible to sand 24 hours later. This has never happened to me before with Featherfill. I stripped it all off with acetone and lacquer thinner. I am thinking of using a fresh gallon of Slick Sand and starting over. The primer on the car was not affected by the lacquer thinner so I am thinking it is some sort of catalyzed primer. I am painting the car with some Centari factory pack that I have had for quite a while. I also have some left over Fill and Sand from Dupont that I might use. Any ideas on what went wrong with the Feather Fill ? Thank you.