was there any sediment at the bottom of your container? I had some lurecraft medium formula that has separated and the bottom was caked solid. I bought it at a yard sale. was told that it was about 3 years old. I stirred, shook and stirred some more while digging into it. finally got a good mix and has been working ok. I have been adding a little hardener here and there. For $15 for the full gallon, I'm getting a lot of mileage out of it.
I'm sorry. I digress. Ideas? make sure you got it mixed well. add some hardener.