Nice job on them splits Osage Outlaw,don't get much clearer than that. DV,I never
leave the sap wood on if I remove the bark.It will almost always will do just what yours did if you leave the sap wood,it will split/check and will usually go down into the heart wood,so I take it off and seal the back or leave the bark on until I am ready to use it.
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Less risky to take the bark and sap off and seal,that way no bugs,but I still usually leave it on.
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Pappy