Use a 4x4 block of wood and place it inside the good section of gutter as you cut the bad section out with a hacksaw.
How to replace a gutter section.
Position the new corner and drill holes for the pop blind rivets.
Drill holes in the overlapping gutter sections to match the rivets you will be using.
Hang the new gutter next to the old one and then slide the patch under the seam.
Use a screwdriver or hammer to disconnect the brackets or other mounting hardware.
Long replace the entire section with new material.
This will allow for some overlap.
Loosen downspout wall straps and pull the downspout away from the house.
Insert wood spacers in the gutter near each hanger before prying.
When drilling try to use the same holes from the old gutter corner.
Section from the box miter with a tin snips and you ve got yourself a custom slip joint.
With a caulk gun apply roofing cement to the existing gutters and position the replacement section so that it overlaps about an inch on either side.
If the damaged area is more than 2 ft.
Disconnect the downspout from the elbow below the gutter drop outlet.
Hardware that holds gutters against the roof varies in design but all attachment systems are quite straightforward.
If the holes are larger than nail holes use tin snips to cut a strip of flashing the same amterial as the gutter wide enough to fill the area.
Measure the section of gutter you removed and add about 2 inches.
Remove gutter hangers in and near the damaged area.
As shown remove the retainers and connectors.
2 cut out damaged section.
After removing the old corner clear away the old sealant with the 121 high speed cutter.
This will keep your gutter in.
Apply plastic roofing cement over small holes.