PATCHY cure , mmmm !!! causes that i can think of Not mixed peoperly
would be my number one , was the container round or square ? round containers the catalyst can and does go up the sides
and cling when you stir , Square containers the catalyst does the same but the 4 corners never get mixed properly and its quite hard to do a 100% MIX IN a square container .
When you say its still tacky doesnt mean that much !! what about the resin is it hard or soft ? can you scratch resin off with you fingernails ?? .
If you have used waxed resin and it been sitting in the drum for a while all the ingrediance thats in the resin starts to separate out and this happens quiet quickly if the tempratures are up , light stuff floats to the top ,heavy to the bottom , even the promoters in the resin will separate as well , so if you didnt shake or stir or mix the resin container before you started
thats another possability .
By the time you got to the bottom all the goodies that are left are basicly the dregs with stuff all good stuff in it as you have used all the good stuff already .
Glass is another possability !!, if its been laying around on a floor or even leaning against a concrete wall ,it could have moist patchs
and being damp the moisture kills the resin
and it will never reach it full potentual hardness ever !! even if you try to cook it with lots of heat .
Even a brush or roller thas been in a pot of acetone or what ever you have used to clean you gear and not shacken out properly can do a simular thing by dilluting the resin
to the point where it has little guts left in it .
Again its like poking a stick in the dark ,with out actually seeing what you have got all we can do is speculate as to the causes . Remedy is easy !! just grind it off and reglass it , simple and done !!