My english is not the best, but i'll do my best to be clear.
Step 1: Materials and tools
75mmx1m PVC sanitary tube
1 screw and nut
4 cable ties
i recomend the use of safety glasses and gloves.
of course you need a bike to mount them and depending on the geometry and accesories of the bike the result and procedure may vary.
Step 2: First Step
i chose a 75mm (3") tube since the tires i use are 2" wide (50mm)
so measure your tires before you buy.
Step 3: Curved mud guard
so i messured the leght of the area that was going to be covered by the guard.
and cutted one half tube to that leght.
After doing so, i made parcial cuts to the tube so bending it where easier.
Then i heated the tube with the torch so the form i gave the tube remains in time.
then a few holes and cable ties and screws and you are done.
SEE where you can use screws or ties before you make anything!
Step 4: Front fender
so i prefered a straight tube for the front fender
you have to make 4 holes for the ties
i bended the corners for safety, with the gas torch.
Step 5: End
I hope it helps!!