3. Cut the Top and Bottom of the Cans
The top of each can needs to be cut as shown, creating a oblong hole that’s roughly double the size of the manufacturer’s pour tab.
Follow this up by drilling a hole through the bottom of each can.
A good set of metal shears would be mighty helpful for this step if you can get your hands on a pair.
4. Put Fire Block Sealant on the Top of the Cans
You will use this process on the bottom and middle can for each row of three high so that they stick to each other.
The fire block will fix your cans together and improve insulation value in your system. It’s not likely that you’ll see temperatures quite that hot.