Thanks guys, you are right I am not alone in having trouble with this stuff. If only I had Googled "trouble with POR 15" before I wasted my money on the stuff.
There you go, I should have left the inside of the tank alone, it was not leaking , I just wanted to do the best job possible having gone so far with the bike.
Hey, ho, happy days. Not!
White vinegar and gravel plus lots of shaking (I don't have a cement mixer) looks to be the order of the day. One substitute for gravel suggested has been a hand full of dry walling screws, easier to get out of the tank as you can use a magnet. any one see an issue with this?.