crane boom.

[cosworth34677]

ok i really want o make a crane. but the boom is what putting me off. the idea is to have a crane the stand 4 foot from top to bottom .
and able to lift about 3lbs. my welding skill is not the best i was thinking of solder in the parts but i don't think it would be that strong. any idea of a type material that is easy to cut bend and glue or solder together? i think my biggest problem is going to be me more then anything, im not the most patent and persistence guy. so any idea and help would be great

oh is styrene a good idea for a ladder type boom?