Step 1
Look over the section of flue pipe you want to replace. On both ends it will be attached to other sections of flue pipe with sheet metal screws.
Step 2
Unscrew the sheet metal screws from the section of flue pipe you wish to replace. Slide the flue pipe out of the other sections of flue pipe.
Step 3
Measure the length of the flue pipe and prepare a replacement piece by cutting a piece of flue pipe to the correct length using your snips.
Step 4
Crimp one end with your pipe crimper. Slide the crimper over one end and squeeze to place a crimp on the pipe. Unsqueeze the crimper, position it next to the crimp and squeeze again. Repeat this until it is crimped around the entire end.
Step 5
Slide the flue pipe into place between the existing sections of flue pipe. Each end of the flue pipe should overlap the other section by 1 1/4 inches.
Step 6
Install sheet metal screws on each end of the flue pipe to secure it in place. Use three to four sheet metal screws per connection.