I agree with Pappy. I bend wood for musical instrument sides all the time, and seldom do it with dry heat. Soak the wood - especially Ash - for a day or three. Not the whole bow; just one tip - stand it in a pickle bucket. If you want you can now boil the tip for awhile. Then clamp the tip in your bending jig and start heating with your heat gun. As the wood starts to dry, slather it with a wet rag. Gently apply the pressure to bend. With ash as thick as a bow tip this is not a 15 minute job. Your "calibrated" finger isn't very reliable for measuring heat penetration. You can also wrap a wet rag over the area being bent and heat that - essentially a localized steaming.
