For my first property, I took a HELOC loan on my primary residence.

If you plan to use another kind of financing like a portfolio loan, or just cash from a HELOC on your primary residence, or whatever else then you buy within the LLC if you wanted.

Now that it's paid off, we opened a HELOC to leverage that equity for other deals.

In a matter of a few months, I had paid them off--used all my cash reserves knowing that I could always dip into the HELOC if an emergency comes up.

I would advise against using a HELOC to buy a property.

If that is your plan, you have a few options.1) Get a HELOC and keep the balance at $0 until you are ready to buy your rental home, so you do not pay interest in the meantime.  

I would recommend looking into a 401k loan, HELOC or some other creative way to purchase the property.

A HELOC or home equity line.

(The LOC and HELOC are sizeable so the interest is very significant). 

I need to check with them before throwing names out here but my biggest surprise was that in talking with Mountain West Bank about financing they offered me an HELOC at 75% of the purchase price without any seasoning period.