I tried this on some 6 pack carriers that I made for Fathers Day last year. Getting it to look like your reference pic was pretty tough for me, but I was just using a benzomatic torch...like the soldering kind. I ended up going full char, and then sealing the crap out of it....I like the finished product. Also, the wood shrinks when burned! I had everything fully assembled and then charred it and my corners all shrunk up!
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