So I needed to fix my bikes front fender, it was broken up in many places. I fixed it by using another broken fender as extra material and joined the two fenders together.

I made this instructable mostly to show a handy way to join plastic sheeting using zipties. I have been using this method for a lot for quick repairs where the material isn't put under too much stress.

Supplies

Power drill or other means to make holes in the plastic

Saw (I used an iron saw)

Zip ties

Step 1: Cut Fenders Where Needed and Join With Zipties

Remove fender
Cut off the bad parts of the original fender, cut the donor fender to the wanted length and place at the end of the original fender with some overlap
Clamp them together with locking pliers or other means
Drill out pairs of holes in the fenders at four locations like in the picture
Secure the joined fenders with zipties
Install repaired fender on the bicycle

Step 2: Done

The end result looks quite nice. As a bonus the repaired fender extends further down at the low end, which gives my feet better protection from spray in wet weather.

This method can be used for many types of plastic sheeting joinery.