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Hi, Hate to back you up on progress, but you should have a damper [butterfly] type valve inside the pipe to regulate heat and make wood last. Just like a normal wood stove. Also, pipe should always be lapped so creasote runs back into stove and won't go all over. Just a couple ideas while you are in the building stage. You may be able to seal joint with good sealer from auto store, they have super high temp. compound. Good Luck, Ron P.S. Looks Great