Looks like too much heat to me. Reminds me of my first attempt to tune 3 blades by heating the end of the arrow to turn insert, lol. What a fiasco, although I'm sure it works well w/ aluminium arrows. You have to keep the heat well away from carbons, that's why I use a long piece of threaded rod screwed in, I can heat the rod 3-4"away from shaft til the glue loosens and insert pulls out.