Equity to "Buy and hold method"

[Tri Ly]

I read a lot of buy and hold strategy here that first, you buy a property then rent out. Then take out the equity in the property to buy another. My question is: when you take equity out of your 1st property, do banks allow you to take all of it? Or minus the downpayment (since 20% is the limit for PMI) what is the max percentage of equity in your experience. What is the method (Heloc, home equity loan etc)? Thanks.