How do you make a surf board?

Very carefully! Seriously, HB Snake gave you a great answer. he's made lots more boards than I have. The few that I made as a kid, years ago, were lots of fun to make, but they turned out pretty crappy. (Of course my buddies and I thought they were great!). We would would borrow a board from which ever pal bought the latest hottest, board, and we would trace the outline as a template on blanks we scavenged by peeling down old longboards (the boards we destroyed back then would be worth $thousands now). But, if you want to play in the garage over the winter, here are a couple web sites to explore. http://www.surfersteve.com/introduction.htm http://www.foamez.com/ I don't know what the remark about "denser" is supposed to mean, but be forewarned, you might not be an overnight success.

your better of just buying one. If you make it, It may be more dense on one side and will throw you off when your riding.