Brr Financing Question

[Evan Shuey]

I have a question that i'm sure has been answered but I cannot find about financing and re-financing. 

Lets say I want to buy a fixer for 50k and I want to put 20% down and go through a local bank. Then rehab and prep the property for rent in 8 weeks and I want to get it appraised and refinanced so I can get my money out. It sounds like if I financed this loan initially, that bank may appraise and re-finance my property after a 6 month seasoning period right? But that means my capital is tied up for a least 6m.

Assuming the above is true, how are investors able to get a house, rehab it and refi it so quickly? Are they buying with cash first then leveraging deffered financing? (ive heard there can be weird HUD rules with this that can prevent you from getting market value, but I could be wrong) Are they using short term loans with higher rates for a few months then flipping over to conventional?

I am in a situation where I have the capital for 20% down and rehab costs, but i'm not able to buy the house for cash too yet. 

Thanks for the help