cage question?

can i build a cage with the frame built out of pinewood? would it be harmful to the snake.

I guess it would. I know that pine bedding, it's harmful for snakes, or lizards but if it is possible, avoid using pinewood.
I keep my 3 1/2 ball in a 30 gal. glass tank, and that's big enough for him. They don't like big enclosures, unless you are thinking to get a burmese or retic, you don't need to build big cages, but is your choice. Maybe some of the guys here, can give you better info about pinewood.
Good luck and take care of yourself and your pet !

It wouldnt be harmful to the snake if you seal it with 4-5 coats of polyurethane and let it cure for 3-4 days in the sun. But then why wouldnt you just use whitewood its cheaper than pine...

Exactly. Just use some high grade exterior ply sealed with water based poly. Much cheaper.