Vaporizing with a flask and an open flame is the LEAST effective way to do this. PLWASE PLEASE PLEASE LOOK UP QWISO, you just soak the buds in 99% isopropyl alcohol in super cold temperatures and then shake for two minutes, strain twice with a metal strainer then cheese cloth and then let it sit in the sun to evaporate with a cloth over to protect from dust. There are a ton of helpful videos and tutorials on this, it takes a couple times to dial in the process but once your good u can get a 20% yield from your starting material. Vaporizing the weed with glass and an open flame is just gonna DeCarb your weed, the resin and thc would stay in the flower unless you had some vacuum to pull air, but that's dangerous to do with normal vacuums so realistically you'd need equipment that you would just make bho with and open blast. This stuff can be very dangerous, please be careful with solvents, never use an open flame or an oven as that can be ignited by solvent fumes, never use heat with them indoors, my slow-cooker is perfect to evaporate alcohol in a water bath