This seems like a really novice question, thats because im 15 and frankly have no clue on which wood is strong and is not
I have a 4 ft long desk that i have a 4x2x2 on atm and i want a 6x2x2, so i was wondering what wood i need and also if anyone has built anything like this size, what is the cost for the wood? I'm not sure wether to built a whole new stand or just a 2 foot ad on to the desk, By the way the desk is a fairly old, aka well built, desk which is soppurted by 6 1.5x1.5's 
I have a 4 ft long desk that i have a 4x2x2 on atm and i want a 6x2x2, so i was wondering what wood i need and also if anyone has built anything like this size, what is the cost for the wood? I'm not sure wether to built a whole new stand or just a 2 foot ad on to the desk, By the way the desk is a fairly old, aka well built, desk which is soppurted by 6 1.5x1.5's 