Virginia beach is haveing a pirate themed event and i was wondering if i used zipties to secure it in its sheath could i carry my sword for my costume.
First of all, don't wear a mask in public (unless you're a kid on Halloween); that itself is actually illegal (even if you were wearing it to express your First Amendment rights!). If your sword is only concealed by a sheath which is obviously made for a sword, and the sheath and the handle are entirely visible to the public, I don't see anyone reasonably calling it a "concealed weapon".
I would transport the sword in the trunk your car, not on or at your side, in case a cop stops you to give you a ticket, so it is not viewed as "concealed" in that circumstance. I would not go to a bank, store or ATM where there are other people present, who might be made nervous by your sword. I don't see your zip ties making a practical difference, unless as a good excuse not to take it out of the sheath when people at the party ask you to do so.