Homebrew PCBs

I decided to try some Plumber's paste, (solder-it brand Plumber's
Solder) for tinning some pcb's.

The paste itself is a lot coarser that I would have thought.

I tried melting a bit with a soldering iron and it didn't flow. It just
made a mess.

My next trial is either on a hotplate or in a toaster oven. Probably the
toaster oven since it's already plugged in :)

For those of you who have successfully used it for tinning, any
suggestions for time/ temperature in an oven or on a hot plate?

How did you manage an even coating?

Thanks,

Myc