||07-19-2015 01:54 PM
I can't help you with sources for Tea Tree Oil, but....
Australian friends of ours, cruising guests on SV Watermelon up the Australian coast from Mooloolaba to Darwin, used Tea Tree Oil for lots of things, and I discovered that the smell of it made me quite ill.
For mold-proofing, have you tried good old-fashioned 20-Mule Team Borax? You can make a super-solution and paint it on your wood.
It is also used to get rid of cockroaches (old way, mix boric acid/Borax with sweetened condensed milk to make a paste that you can roll into little balls and put in your bilges.) Household use, mix with simple syrup (equal parts sugar & water), put around near ant nests - kills them, too).