What makes the SCA unique from other medieval re-enactment groups is that our fighting is not choreographed. What makes this possible is our armour standards and weaponry. The SCA sword is essentially a club: it's a stick of rattan wrapped in fibre tape and duct tape, given a blade side (defined with electrical tape), with a basket hilt.
After getting your stick of rattan, cut it down to a nice size. A "standard length" for a sword is a length that enables you to swing it loosely back and forth by your side and the tip just touches the ground - but, of course, you can make it to whatever you feel comfortable with. Wrap your rattan in fibre tape, then a good few layers of duct tape. Decide which side feels comfy and which side would make a good blade side (there are various arguments about which way the blade should go, but in the end it's UP TO YOU). Attatch the basket hilt. You may also like to add a thrusting tip.
There is your new SCA sword!
All other SCA weapons are basically a variant on this.