Since substantial secondary voltage can easily damage the first coil, a selfmade thin secondary is advised if you'd like to pump a lot more watts in to the flyback. The coil has to be no more than 1 mm thick! In such a case, as opposed to paraffin wax, use http://miloqyhmk.mybuzzblog.com/14646547/phone-and-wifi-jammer-for-dummies