i am going to try & replace my gas hotwater heater for my house (40 gal.)?

with gas u shouldn't take the risk but soldering is not that hard clean the pipe shiny with wire wool then use copper fittings with solder already in them or u can get with out then you have to add solder to the join. once u cleaned the pipe around the outside normally i count 10 to 15 secs of cleaning then paste flux around the outside of the pipe and inside the joint fitting (remember to complete the join ie if it a tee add all 3 sides into join before soldering or heating). once join is together apply heat from a blow lamp heat each section of the joint and u should see a silver ring appear then move to the other side of the joint once all joins show silver solder cool down with wet cloth and jobs done if u use with out solder once heated touch solder to pipe if it melts feed the joint and then pull away. i only advise for water as theres more the joining a pipe to fit a boiler

kash
August 2010