How to Tell Windows to Ignore One of Your NICs

My testing computer runs VMware Workstation and has two network cards. One of the NICs is connected to my production network cards and is my main NIC. The other NIC is used to connect any virtual networks within my VMware Workstation environment to the internet if I need to. I didn't want the computer to send any traffic out to this testing NIC. Of course, disabling that NIC in Windows would have rendered it unusable to my VMware environment. Here's how I got around that:

1. Opened the properties of my test NIC.
2. Opened the Internet Protocol Version 4 (TCP/IPv4) properties.
3. Click "Advanced"
4. Uncheck the box that says "Automatic Metric" and enter a high number. I used 500.
5. Hit OK multiple time to close the dialog boxes and apply the setting.

Now, when Windows needs a path, it will see the high metric and use the production NIC. My production VMs will only see the NIC I assign to to them (the test NIC with the high metric) and won't have any choice but to use the test interface for outgoing traffic.