3. A good pressure washer
You need something that's rated over 1500 PSI, with 1800 to a maximum of 3200 PSI being ideal. Water flow is also important, so make sure your machine has at least 7 to 8 litres per minute flow too. Attach the gun/Cannon to the machine with the right adapter and you’re ready to foam.
We’ve used a Gerni brand pressure washer that’s rated at 1800 PSI in our videos and images here.