Debt free other than mortgage....HELOC for investing?

[Martin Silverstrim]

We're purchasing our first rental at the beginning of 2020. I'm funding that through cashing out some stocks and using some savings with a 30 yr mortgage. Hoping things go well and looking to purchase another prior to the end of the year. I have enough that I could do the 2nd property down payment without issue, but if I'm looking at a third property soon thereafter I'd need to find another means of doing a down payment. We have about 110k equity in our house valued at 420k. I'm not worried about paying off my primary residence mortgage as my wife and I both have secure jobs. Any advice on using HELOCs for future purchases and then using cash flow to pay down the HELOC? Do you consider this risky?I just don't want to overextend myself. I think a property a year is reasonable. That said, with cash flow from two properties (and then three, I think I could come pretty close to being able to purchase a new property at least every 18 months between cash flow and additional savings, basically paying off the HELOC each time and repeating the process.

I appreciate your input as I'm new to this but am seeing my plan develop and move towards reality. Thanks