Rich from West Linn, Or writes
Then some holes appeared. Now there's a third hole. We did kill one... maybe a false powderpost beetle? Can we take this butcher block top off and treat the unfinished bottom (top has had Linseed oil finish)? Is Boracare toxic enough that we could not use this butcher block top for food preparation after applying the Boracare to the bottom (about 1.5" thick)?
As long as the top is sealed then you can safely apply Boracare to the underside if unsealed and it will penetrate through the wood. It would be recommended to allow the butcher block to dry for 24-48 hours before using again. Any food contact surfaces treated with Boracare must have a sealant applied after the Boracare has dried.
Answer last updated on: 04/01/2016