Hello everyone I have been in the field for about a year now. I started out riding along with a tech who has been in the field for 30 years. He has become my mentor and I have learned a lot from this individual although he chooses not to follow industry standards often hes kind of hard headed and stuck in his ways. I personally want to grow more keep up with industry standards, follow proper procedures and become a grade A tech. Although i am thankful for him taking me under his wing I guess I feel like i hit a dead end in my learning with this individual. That being said I feel a week point for me right now is airflow and learning proper duct design. I'm attending a manufacture training class on air flow this week but those classes are only so in depth. What is the best way to learn and master this section of are business. Books? A specific class or seminar? any input would be great.