You are essentially taking on debt to acquire more debt. If the real estate market dips, you could end up "underwater" on both properties. Strategic Tips for Success
Using the HELOC to cover the 20% to 25% down payment required for a traditional investment property loan. The Benefits using heloc to buy rental property
Because a HELOC is secured by your home, the interest rates are typically much lower than personal loans or credit cards. You are essentially taking on debt to acquire more debt