Gravity reading problem

[Hunter7922]

Newbie question on hydrometer gravity reading.
ok, well I've read a lot of New distiller reading Lounge and I think I'm defiantly getting there.

I have done about 90% of the cleaning and will run the ethanol cleaning this week end, but in the mean time I though that since Uncle Jesse's corn mash takes about a week to ferment I would start it now and finish my still cleaning and test runs.

So the Mash I made was 9 lbs cracked corn (bird seed - no preservatives), 8 lbs cane sugar, 5 gal water (2.5 gal I heated up to 180 deg to dissolve the sugar). I then waited until temp was 104 and before I added Red Star dry active yeast I took my Gravity reading.

My Hydrometer did not sink at all, why?
Temp was to high, to much sugar to corn, not enough water....

Any help would be great.

Thanks