Homebrew PCBs

Hello all,

OK, I take up electronics as a hobby. Hit roadblocks, find this yahoo 
group. Read like crazy and figure out how to make PCB's using the 
laser toner method. Great advice, get process down to 99% success 
rate.

Then I see a picture of a great PCB tinning job here - I think from 
Derek Hawkins. So I read, order some tinning paste (McMaster Carr 
#7774A11, page 3286 in online catalog), get a toaster oven, and 
voila, all should be set. But can't seem to do this one, and need 
advice from the experts in this group again.

I bring the oven up to ~440F degrees (according to Mcmaster, the 
melting range is 426-454.) and stabilize it (as best a toaster oven 
can). Bought a thermometer to put in the oven to check temp. Clean 
the PCB with acetone before coating to be sure no junk on it. Coat 
with ever so slightly water diluted paste, and put in the oven. 
Results:

1) I get a bunch of nice spherical silver solder balls sitting in a 
field of dried out grey mud (ie, the solder paste without the solder 
balls, dried out and coating the pcb)

I figure I don't have the heat high enough, but when I turn it up it 
just "burns" the paste.

Can anyone offer some suggestions as to why I get dried out paste 
with solder balls growing in it?
 
Thanks,
M

PS - I get the smae result if I dont dilute with water and just use 
right out of the jar.