VIA's, how much heat is too much?

[pcsmasher]

I'm trying to find the answer to my question, but all I read is "too much heat." That's not very specific. How much, is too much?

There is one quick way I'm thinking of, tell me if it's a good idea. This will require 3 hands . After the via point is cleaned, someone could hold the stripped wire on the via point, and I could put solder on the wire very near the via point. Since the solder is hot, it should slide down the wire and onto the via point. Therefore soldering the wire onto the via.

[loy]

u can add solder to the via jut solder like u would like to a pad. Too much heat is like more than 2 secs