Have 100K cash, want to start building a rental portfolio.

[Anthony Cline]

I'm 29, and here are my financials.  Ihave 100K in cash. Through very frugal living, I'm able to save around 90K per year to put towards this.  I also have access to 30K line of credit (hard cash guy).  

The plan:   To buy a duplex for around 70K in the Midwest, saving 30K for an emergency repair/vacancy fund.  I would then rent all sides of duplex out.  

Question:  Suppose I own this property worth 80K outright, and both sides are rented.  Can I use this property to obtain a loan for say 60K, purchase 2 additional duplexes, using 30K for each unit, and say 50K hard cash loan on both, then aggressively pay the mortgage off with my extra income, pay those off, and then own 3 duplexes, which I could leverage 2 of those against say 4 more duplexes rinse, repeat?