adding weight to engines

[tweetsieengineer]

i just bought a n scale 2-6-2 this weekend and i am looking to add some weight to it...i havent ever done this so im looking for any do's and donts.....im looking to place some lead into the sand domes on the engine to give it more traction.  I know not to short out the motor and stuff.  But how much is to much to add and has anyone attempted this and what were the results. I only paid 30 for the engine so if i burn it up im not out much.

[Train Nutz]

Make sure you use moldable lead weight as this makes the job easier to do. (Also make sure you wash your hands after handling any kind of lead as this can cause all kinds of serious problems from digestion to brain damage. So please protect yourself. Latex gloves here are a big plus!)
Add the weight were you can were it can be placed over the top of the drivers to produce more of a downward force creating more traction. The lead can be place in the loco shell or on the frame frame were there's room and hidden from sight. I don't know if it's possible to over weight a steam loco as most of the time there isn't that much space inside them to begin with. I would test the engine first  by adding cars to the point it starts slipping on a straight section of track. Then apply weight to it to see if it gains traction to pull the same set of cars. Hopefully at this point you've created some traction by the downward force of the added weight.

                                    Train Nutzzzzzzzz